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The condenser is located in the air flow next to the engine cooling radiator. The condenser is a heat exchanger that allows the high-pressure refrigerant gas being discharged by the compressor to give up its heat to the air passing over the condenser fins.
OPERATION
When the refrigerant gas gives up its heat, it con- denses. When the refrigerant leaves the condenser, it has become a high-pressure liquid refrigerant. The volume of air flowing over the condenser fins is crit- ical to the proper cooling performance of the air con- ditioning system. Therefore, it is important that there are no objects placed in front of the radiator grille openings in the front of the vehicle or foreign material on the condenser fins that might obstruct proper air flow. Also, any factory-installed air seals or shrouds must be properly reinstalled following radia- tor or condenser service.
The condenser cannot be repaired and, if faulty or
damaged, it must be replaced.
REMOVAL
REMOVAL - 3.7, 4.7 and 5.7L ENGINES
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)
(1) Disconnect and isolate the battery negative
cable.
(2) Recover the refrigerant from the refrigerant system. (Refer to 24 - HEATING & AIR CONDI- TIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT RECOVERY)
(3) Disconnect the discharge line refrigerant line fitting at the condenser inlet. (Refer to 24 - HEAT- ING & AIR CONDITIONING/PLUMBING - STAN- DARD PROCEDURE - A/C LINE COUPLERS) Install plugs in, or tape over all of the opened refrig- erant line fittings.
(4) Disconnect the liquid line refrigerant line fit- ting at the condenser outlet. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLERS) Install plugs in, or tape over all of the opened refrigerant line fit- tings.
PLUMBING
24 - 40
A/C CONDENSER (Continued)DR
(5) Disconnect the condenser cooling fan electric
connector.
PLER) Install plugs in, or tape over all of the opened refrigerant line fittings.
(6) Remove the two nuts that secure the condenser
(5) On diesel engine models:
studs to the upper cross brace. (Fig. 5).
(a) Remove the two screws that secure the brackets on the passenger side end of the con- denser to the charge air cooler (Fig. 6).
(b) Remove the two nuts that secure the driver side end of the condenser to the studs on the charge air cooler.
(c) Remove the condenser from the vehicle.
Fig.5CondenserModule
1 - Condensor Module Mounting Screw 2 - Front Cross Member 3 - Lower Module Mounting Flang 4 - Fan Assembly Mounting Screw 5 - Fan Assembly Mounting Screw 6 - Condensor Mounting Tabs 7 - Condensor Fan Assembly 8 - Fan Power Connector 9 - Condensor Module Mounting Screw
(7) Remove the condenser and fan assembly from
the vehicle.
REMOVAL - 5.9L DIESEL ENGINE
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)
(1) Disconnect and isolate the battery negative
cable.
(2) Recover the refrigerant from the refrigerant system. (Refer to 24 - HEATING & AIR CONDI- TIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT RECOVERY)
(3) Remove the nut that secures the block fitting to the stud on the condenser inlet, and disconnect the discharge line from the condenser. Install plugs in, or tape over all of the opened refrigerant line fittings.
(4) Disconnect
the refrigerant
line fitting that secures the liquid line to the condenser outlet. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMB- ING - STANDARD PROCEDURE - A/C LINE COU-
Fig.6CONDENSER-DIESELENGINE
1 - Discharge line to condenser 2 - Condensor mounting bolt 3 - Liquid Line 4 - Condenser mounting bolt 5 - A/C condenser 6 - Condenser mounting bolt 7 - Condenser mounting bolt
REMOVAL - 8.0L Engine
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN TEH FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - WARNING) AND (Refer to 24 - HEATING & AIR CON- DITIONING/PLUMBING - CAUTION).
(1) Remove battery negative cable. (2) Recover refrigerant from a/c system(Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE).DR A/C CONDENSER (Continued)
NOTE: Removal of the front bumper on the V-10 is required, failure to do so could result in damage to the condenser assembly and the bumper.
PLUMBING
24 - 41
(3) Remove the front bumper assembly from the - FRAME & BUMPERS/
vehicle(Refer BUMPERS/FRONT BUMPER - REMOVAL).
13
to
(4) Remove hood latch bolts and set hood latch assembly aside(Refer to 23 - BODY/HOOD/LATCH - REMOVAL).
(5) Remove a/c lines from condenser(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/A/C DISCHARGE LINE - REMOVAL) and (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/ SUCTION LINE - REMOVAL). Install plugs or tape over all open connections (Fig. 7).
Fig.8A/CCONDENSER
1 -A/C shroud mounting bolt 2 - Hood latch bolt 3 - Hood latch assembly 4 - Hood latch bolt 5 - A/C shroud mounting bolt 6 - A/C discharge line 7 - A/C liquid line 8 - Condenser to shroud mounting bolts (5) 9 - A/C condenser 10 - Condenser to shroud mounting bolts (5)
INSTALLATION
INSTALLATION - 3.7, 4.7 and 5.7L ENGINES
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION - REFRIGERANT HOSES/LINES/TUBES PRECAUTIONS)
Fig.7CONDENSERLINES
1 - Discharge line to condenser 2 - Mounting nut 3 - Mounting nut 4 - Liquid line 5 - A/C condenser shroud 6 - A/C condenser
(6) Remove two bolts from top of condenser shroud
assembly (Fig. 8).
(7) Lift condenser and shift assembly to passenger
side of vehicle and remove from vehicle.
(8) With condenser and shroud on a clean flat work area remove condenser retainer screws and sep- arate condenser from shroud.
(1) Install the condenser lower dowel pins to the
bottom of the support rail.
(2) Position the condenser until both of the con- denser studs are installed through the holes in the upper support rail. Tighten the mounting nuts to 5.3
N·m (47 in. lbs.).(3) Remove the tape or plugs from the refrigerant line fittings on the condenser outlet and the liquid line. Install the liquid line or the liquid line jumper to the condenser outlet. (Refer to 24 - HEATING &
PLUMBING
24 - 42
A/C CONDENSER (Continued)DR
AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLERS)
(4) Remove the tape or plugs from the refrigerant line fittings on the condenser inlet and the discharge line. Connect the discharge line to the condenser inlet. (Refer to 24 - HEATING & AIR CONDITION- ING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLERS)
(5) Connect the battery negative cable. (6) Evacuate the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM EVACUATE)
(7) Charge the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM CHARGE)
NOTE: If the condenser is replaced, add 30 millili- ters (1 fluid ounce) of refrigerant oil to the refriger- ant system. Use only refrigerant oil of the type recommended for the compressor in the vehicle. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING/REFRIGERANT OIL - DESCRIPTION)
INSTALLATION - 5.9L DIESEL ENGINE
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION - REFRIGERANT HOSES/LINES/TUBES PRECAUTIONS)
(1) On diesel engine models:
(a) Install the driver side condenser mounting brackets over the two studs on the charge air cooler.
(b) Install the two screws that secure the brack- ets on the passenger side end of the condenser to the charge air cooler. Tighten the mounting screws to 10.5 N·m (95 in. lbs.).
(c) Install the two nuts that secure the driver side end of the condenser to the studs on the charge air cooler. Tighten the mounting nuts to 10.5 N·m (95 in. lbs.). (2) Remove the plugs or tape from the refrigerant line fittings on the liquid line and the condenser out- let. Connect the liquid line to the condenser outlet. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLERS)
(3) Install a new gasket and the discharge line block fitting over the stud on the condenser inlet. Tighten the mounting nut to 20 N·m (180 in. lbs.).
(4) Check that all of the condenser and radiator
air seals are in their proper locations.
(5) Connect the battery negative cable. (6) Evacuate the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM EVACUATE)
(7) Charge the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM CHARGE)
NOTE: If the condenser is replaced, add 30 millili- ters (1 fluid ounce) of refrigerant oil to the refriger- ant system. Use only refrigerant oil of the type recommended for the compressor in the vehicle. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING/REFRIGERANT OIL - DESCRIPTION)
INSTALLATION - 8.0L Engine
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - WARNING) AND (Refer to 24 - HEATING & AIR CON- DITIONING/PLUMBING - CAUTION).
(1) If the condenser was removed from the shroud,
install it and tighten the mounting screws.
(2) Install the condenser and shroud in the vehicle. Make sure the lower mounting flanges are positioned correctly before installing the two mounting screws to the radiator brace. Tighten the screws to spec.
(3) Remove and plugs or tape installed over the
condenser connections and the a/c lines.
(4) Install the lines to the condenser(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/A/C DISCHARGE LINE - INSTALLATION) and (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/ SUCTION LINE - INSTALLATION).
(5) Install the hood latch assembly(Refer to 23 -
BODY/HOOD/LATCH - INSTALLATION).
(6) Install the front bumper assembly(Refer to 13 - FRAME & BUMPERS/BUMPERS/FRONT BUMPER - INSTALLATION).
(7) Evacuate the a/c system(Refer to 24 - HEAT- ING & AIR CONDITIONING/PLUMBING - STAN- DARD PROCEDURE).
DR A/C CONDENSER (Continued)
NOTE: If the condenser is replaced, add 30 millili- ters (1 fluid ounce) of refrigerant oil to the refriger- ant system. Use only refrigerant oil of the type recommended for the compressor in the vehicle(Re- fer to 24 - HEATING & AIR CONDITIONING/PLUMB- ING/REFRIGERANT OIL - DESCRIPTION).
(8) Charge the a/c system(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE).
(9) Install the battery negative cable.
A/C CONDENSER FAN REMOVAL - CONDENSER FAN (GAS ENGINE ONLY - 3.7, 4.7 & 5.7L)
(1) Remove and isolate negative battery cable. (2) Remove condenser assembly(Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING/A/C CONDENSER - REMOVAL).
(3) Place condenser assembly on a flat work area and remove screws holding fan assembly to con- denser.
(4) Separate fan assembly from condenser noting
location of all seals for reinstallation.
INSTALLATION - CONDENSER FAN (GAS ENGINE ONLY - 3.7, 4.7 & 5.7L)
(1) Position fan assembly on to the condenser. (2) Check all
fan shroud seals and replace as required then install retainer screws to hold fan assembly to condenser.
(3) Install condenser and fan assembly to vehi- cle(Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING/A/C CONDENSER - INSTALLATION).
(4) Install battery negative cable.
A/C DISCHARGE LINE
REMOVAL
REMOVAL
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)
(1) Disconnect and isolate the battery negative
cable.
(2) Recover the refrigerant from the refrigerant system. (Refer to 24 - HEATING & AIR CONDI-
PLUMBING
24 - 43
TIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT RECOVERY)
(3) Unplug the wire harness connector from the
high pressure transducer.
(4) Disconnect the discharge line refrigerant line fitting from the condenser inlet tube (Fig. 9). (Refer to 24 - HEATING & AIR CONDITIONING/PLUMB- ING - STANDARD PROCEDURE - A/C LINE COU- PLERS) Install plugs in, or tape over all of the opened refrigerant line fittings.
Fig.9A/CDischargeLine
1 - Discharge Line Retainer Nut 2 - Front Upper Cross Brace 3 - Condensor Module Port 4 - Suction and Discharge Line Retainer Screw 5 - Suction Line 6 - A/C Compressor 7 - High Pressure Transducer Connector 8 - Discharge Line
(5) Disconnect the connection that secures the suc- tion line fitting to the accumulator outlet. Install plugs in, or tape over all of the opened refrigerant line fittings.
(6) Remove the screw that secures the suction and discharge line manifold to the compressor. Install plugs in, or tape over all of the opened refrigerant line fittings.
(7) Remove the suction and discharge line assem-
bly from the vehicle.
REMOVAL - 5.9L DIESEL ENGINE
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)
(1) Disconnect and isolate the battery negative
cable.
PLUMBING
24 - 44
A/C DISCHARGE LINE (Continued)DR
(2) Recover the refrigerant from the refrigerant system. (Refer to 24 - HEATING & AIR CONDI- TIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT RECOVERY)
(3) Unplug the wire harness connector from the a/c
high pressure switch.
(4) Disconnect the suction line refrigerant line cou- pler at the accumulator. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLER) Install plugs in, or tape over all of the opened refrigerant line fit- tings.
(5) Remove the nut that secures the block fitting to the stud on the condenser inlet and disconnect the discharge line from the condenser. Install plugs in, or tape over all of the opened refrigerant line fittings.
(6) Remove the bolt that secures the refrigerant line manifold to the compressor (Fig. 10). Install plugs in, or tape over all of the opened refrigerant line fittings.
Fig.10SUCTIONANDDISCHARGELINEREMOVE/
INSTALL-DIESELENGINE
1 - DISCHARGE LINE (TO CONDENSER) 2 - COMPRESSOR 3 - BOLT 4 - MANIFOLD 5 - SUCTION LINE (FROM ACCUMULATOR) 6 - A/C HIGH PRESSURE SWITCH
(7) Remove the suction and discharge line assem-
bly from the vehicle.
INSTALLATION
INSTALLATION
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING -
CAUTION - REFRIGERANT HOSES/LINES/TUBES PRECAUTIONS)
(1) Remove the tape or plugs from the suction and discharge line manifold and the compressor. Install the suction and discharge line manifold to the com- pressor. Tighten the fastener to 28 N·m (250 in. lbs.). (2) Remove the tape or plugs from the suction line and the accumulator outlet fittings. Install the suc- tion line to the accumulator outlet and install fas- tener.
(3) Remove the tape or plugs from the refrigerant line fittings on the discharge line and the condenser inlet tube. Connect the discharge line refrigerant line coupler to the condenser inlet tube. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLERS) (4) Plug in the wire harness connector to the high
pressure transducer switch.
(5) Connect the battery negative cable. (6) Evacuate the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM EVACUATE)
(7) Charge the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM CHARGE)
INSTALLATION - 5.9L DIESEL ENGINE
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION - REFRIGERANT HOSES/LINES/TUBES PRECAUTIONS)
(1) Remove the tape or plugs from all of the refrig- erant line fittings. Connect the suction line refriger- ant line coupler to the accumulator. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLERS) (2) Install a new gasket and the discharge line block fitting over the stud on the condenser inlet. Tighten the mounting nut to 20 N·m (180 in. lbs.).
(3) Install the refrigerant line manifold to the com- pressor. Tighten the mounting bolt to 22 N·m (200 in. lbs.).
(4) Plug in the wire harness connector to the a/c
high pressure switch.
(5) Connect the battery negative cable. (6) Evacuate the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING -
DR A/C DISCHARGE LINE (Continued)
STANDARD PROCEDURE - REFRIGERANT SYS- TEM EVACUATE)
(7) Charge the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM CHARGE)
LIQUID LINE REMOVAL
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)
(1) Disconnect and isolate the battery negative
cable.
NOTE: Removal of the second battery and battery tray is required on the diesel equipped vehicles.
(2) Remove rightside battery(Refer to 8 - ELEC- TRICAL/BATTERY SYSTEM/BATTERY - REMOV- AL).
(3) Remove rightside battery tray(Refer to 8 - ELECTRICAL/BATTERY SYSTEM/TRAY - REMOV- AL).
(4) Recover the refrigerant from the refrigerant system. (Refer to 24 - HEATING & AIR CONDI- TIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT RECOVERY)
(5) Disconnect the liquid line refrigerant line cou- plers at the condenser outlet the mid point connec- tion and the evaporator to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLERS) Install plugs in, or tape over all of the opened refrig- erant line fittings.
(Refer
inlet.
(6) Disengage any clips that secure the liquid line
to the inner fender shield or cross brace. (Fig. 11).
(7) Remove the both sections of the liquid line
from the vehicle.
INSTALLATION
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING -
PLUMBING
24 - 45
Fig.11A/CLiquidLine-GasEngineshown
1 - A/C Line Retainer Clip 2 - A/C Line Retention Clip 3 - A/C Line Retainer Clip 4 - Liquid Line to Evaporator 5 - A/C Line Retention Clip 6 - Evaporator Ports 7 - A/C Condensor Modular 8 - A/C Jumper Line Retainer Nut 9 - A/C Line Retainer Clip 10 - A/C Liquid Jumper Line
CAUTION - REFRIGERANT HOSES/LINES/TUBES PRECAUTIONS)
(1) Install both sections of the liquid line into any clips on the inner fender shield and the dash panel. (2) Remove the tape or plugs from the refrigerant line fittings on the liquid line, the condenser outlet, and the evaporator inlet. Connect the liquid line pieces together and to the condenser and the evapo- rator. (Refer to 24 - HEATING & AIR CONDITION- ING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLERS)
NOTE: Installation of the second battery and battery tray is required on the diesel equipped vehicles.
(3) Install the rightside battery tray(Refer to 8 - ELECTRICAL/BATTERY SYSTEM/TRAY - INSTAL- LATION).
(4) Install the rightside battery(Refer to 8 - ELEC- TRICAL/BATTERY SYSTEM/BATTERY - INSTAL- LATION).
(5) Connect the battery positive cables. (6) Connect the battery negative cables. (7) Evacuate the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING -
PLUMBING
24 - 46
LIQUID LINE (Continued)STANDARD PROCEDURE - REFRIGERANT SYS- TEM EVACUATE)
(8) Charge the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM CHARGE)
SUCTION LINE
REMOVAL
REMOVAL
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)
DR
TIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT RECOVERY)
(3) Unplug the wire harness connector from the a/c
high pressure switch.
(4) Disconnect the suction line refrigerant line cou- pler at the accumulator. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLER) Install plugs in, or tape over all of the opened refrigerant line fit- tings.
(5) Remove the nut that secures the block fitting to the stud on the condenser inlet and disconnect the discharge line from the condenser. Install plugs in, or tape over all of the opened refrigerant line fittings.
(6) Remove the bolt that secures the refrigerant line manifold to the compressor (Fig. 12). Install plugs in, or tape over all of the opened refrigerant line fittings.
(1) Disconnect and isolate the battery negative
cable.
(2) Recover the refrigerant from the refrigerant system. (Refer to 24 - HEATING & AIR CONDI- TIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT RECOVERY)
(3) Unplug the wire harness connector from the a/c
high pressure transducer.
(4) Disconnect the suction line refrigerant line cou- pler at the accumulator. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLER) Install plugs in, or tape over all of the opened refrigerant line fit- tings.
(5) Remove the nut that secures the condenser inlet and disconnect the discharge line from the con- denser. Install plugs in, or tape over all of the opened refrigerant line fittings.
(6) Remove the suction and discharge line assem-
bly from the vehicle.
REMOVAL - 5.9L DIESEL ENGINE
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)
(1) Disconnect and isolate the battery negative
cable.
(2) Recover the refrigerant from the refrigerant system. (Refer to 24 - HEATING & AIR CONDI-
Fig.12SUCTIONANDDISCHARGELINEREMOVE/
INSTALL-DIESELENGINE
1 - DISCHARGE LINE (TO CONDENSER) 2 - COMPRESSOR 3 - BOLT 4 - MANIFOLD 5 - SUCTION LINE (FROM ACCUMULATOR) 6 - A/C HIGH PRESSURE SWITCH
(7) Remove the suction and discharge line assem-
bly from the vehicle.
INSTALLATION
INSTALLATION
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION - REFRIGERANT HOSES/LINES/TUBES PRECAUTIONS)
DR SUCTION LINE (Continued)
(1) Remove the tape or plugs from all of the refrig- erant line fittings. Connect the suction refrigerant line coupler to the accumulator. (Refer to 24 - HEAT- ING & AIR CONDITIONING/PLUMBING - STAN- DARD PROCEDURE - A/C LINE COUPLERS)
(2) Install a new gasket and the discharge line block fitting over the stud on the condenser inlet. Tighten the mounting nut to 20 N·m (180 in. lbs.).
(3) Install the refrigerant line manifold to the com- pressor. Tighten the mounting bolt to 22 N·m (200 in. lbs.).
(4) Plug in the wire harness connector to the A/C
high pressure transducer.
(5) Connect the battery negative cable. (6) Evacuate the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM EVACUATE)
(7) Charge the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM CHARGE)
INSTALLATION
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION - REFRIGERANT HOSES/LINES/TUBES PRECAUTIONS)
(1) Remove the tape or plugs from all of the refrig- erant line fittings. Connect the suction line refriger- ant line coupler to the accumulator. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLERS) (2) Install a new gasket and the discharge line block fitting over the stud on the condenser inlet. Tighten the mounting nut to 20 N·m (180 in. lbs.).
(3) Install the refrigerant line manifold to the com- pressor. Tighten the mounting bolt to 22 N·m (200 in. lbs.).
(4) Plug in the wire harness connector to the a/c
high pressure switch.
(5) Connect the battery negative cable. (6) Evacuate the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM EVACUATE)
(7) Charge the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM CHARGE)
PLUMBING
24 - 47
A/C EVAPORATOR DESCRIPTION
The A/C evaporator is located in the HVAC hous- ing, under the instrument panel. The evaporator coil is positioned in the HVAC housing so that all air that enters the housing must pass over the fins of the evaporator before it is distributed through the sys- tem ducts and outlets. However, air passing over the evaporator coil fins will only be conditioned when the compressor is engaged and circulating refrigerant through the evaporator coil tubes.
OPERATION
Refrigerant enters the evaporator from the fixed orifice tube as a low-temperature, low-pressure liq- uid. As air flows over the fins of the evaporator, the humidity in the air condenses on the fins, and the heat from the air is absorbed by the refrigerant. Heat absorption causes the refrigerant to boil and vapor- ize. The refrigerant becomes a low-pressure gas when it leaves the evaporator.
The evaporator coil cannot be repaired and,
if
faulty or damaged, it must be replaced.
REMOVAL
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)
(1) Remove the HVAC housing from the vehicle, and disassemble the housing halves. (Refer to 24 - HEATING & AIR CONDITIONING/DISTRIBUTION/ HVAC HOUSING - REMOVAL) (Refer to 24 - HEAT- ING & AIR CONDITIONING/DISTRIBUTION/HVAC HOUSING - DISASSEMBLY)
(2) Lift the A/C evaporator out of the HVAC hous-
ing (Fig. 13).
INSTALLATION
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION - REFRIGERANT HOSES/LINES/TUBES PRECAUTIONS)
PLUMBING
24 - 48
A/C EVAPORATOR (Continued)DR
mesh diffuser screen. The O-rings on the plastic body of the fixed orifice tube seal the tube to the inside of the liquid line and prevents the refrigerant from bypassing the fixed metering orifice.
Fig.13DualZoneHVACHousing-(typicalsingle
zone)
1 - Passenger Side Blend Door Lever (if equipped) 2 - Passenger Side Blend Door (if equipped) 3 - Fin Sensor Wire 4 - Lower Blower Motor Mounting Housing 5 - HVAC Evaporator 6 - Fin Sensor 7 - Driver Side Blend Door 8 - Driver Side Blend Door Lever
(1) Insert the evaporator coil into the bottom of the HVAC housing. Make sure that the evaporator drain is clean and unrestricted and evaporator deflector shield is also installed.
(2) Reassemble and reinstall the HVAC housing in the vehicle. (Refer to 24 - HEATING & AIR CONDI- TIONING/DISTRIBUTION/HVAC ASSEMBLY) (Refer to 24 - HEATING & AIR CON- DITIONING/DISTRIBUTION/HVAC HOUSING - INSTALLATION)
HOUSING
NOTE: If the evaporator is replaced, add 60 millili- ters (2 fluid ounces) of refrigerant oil to the refrig- erant system.
A/C ORIFICE TUBE DESCRIPTION
The fixed orifice tube is installed in the liquid line between the outlet of the condenser and the inlet of the evaporator. The fixed orifice tube is only serviced as an integral part of the liquid line.
OPERATION
The inlet end of the fixed orifice tube has a nylon mesh filter screen, which filters the refrigerant and helps to reduce the potential for blockage of the metering orifice by refrigerant system contaminants (Fig. 14). The outlet end of the tube has a nylon
Fig.14FIXEDORIFICETUBE-TYPICAL
1 - DIFFUSER SCREEN 2 - “O” RINGS 3 - INLET FILTER SCREEN 4 - ORIFICE
The fixed orifice tube is used to meter the flow of liquid refrigerant into the evaporator coil. The high- pressure condenser expands into a low-pressure liquid as it passes through the metering orifice and diffuser screen of the fixed orifice tube.
liquid refrigerant
from the
The fixed orifice tube cannot be repaired and, if faulty or plugged, the liquid line assembly must be replaced.
DIAGNOSIS AND TESTING - FIXED ORIFICE TUBE
The fixed orifice tube can be checked for proper operation using the following procedure. However, the fixed orifice tube is only serviced as a part of the liquid line unit. If the results of this test indicate that the fixed orifice tube is obstructed or missing, the entire liquid line unit must be replaced.
WARNING: THE LIQUID LINE BETWEEN THE CON- DENSER OUTLET AND THE FIXED ORIFICE TUBE CAN BECOME HOT ENOUGH TO BURN THE SKIN. USE EXTREME CAUTION WHEN PERFORMING THE FOLLOWING TEST.
(1) Confirm that the refrigerant system is properly charged. (Refer to 24 - HEATING & AIR CONDI- TIONING - DIAGNOSIS AND TESTING - A/C PER- FORMANCE)
(2) Start the engine. Turn on the air conditioning system and confirm that the compressor clutch is engaged.
(3) Allow the air conditioning system to operate for
five minutes.
(4) Lightly and cautiously touch the liquid line near the condenser outlet at the front of the engine
DR A/C ORIFICE TUBE (Continued)
PLUMBING
24 - 49
compartment. The liquid line should be hot to the touch.
(5) Touch the liquid line near the evaporator inlet at the rear of the engine compartment. The liquid line should be cold to the touch.
(6) If there is a distinct temperature differential between the two ends of the liquid line, the orifice tube is in good condition. If there is little or no detectable temperature differential between the two ends of the liquid line, the orifice tube is obstructed or missing and the liquid line must be replaced.
REMOVAL
The fixed orifice tube is located in the liquid line, between the condenser and the evaporator coil. The orifice has filter screens on the inlet and outlet ends of the tube body. If the fixed orifice tube is faulty or plugged, the liquid line assembly must be replace- d(Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING/LIQUID LINE - REMOVAL).
INSTALLATION
The fixed orifice tube is located in the liquid line, between the condenser and the evaporator coil. The orifice has filter screens on the inlet and outlet ends of the tube body. If the fixed orifice tube is faulty or plugged, the liquid line assembly must be replace- d(Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING/LIQUID LINE - INSTALLATION).
ACCUMULATOR DESCRIPTION
The accumulator is mounted in the engine com- partment between the A/C evaporator outlet tube and the compressor inlet.
OPERATION
Refrigerant enters the accumulator canister as a low pressure vapor through the inlet tube. Any liq- uid, oil-laden refrigerant falls to the bottom of the canister, which acts as a separator. A desiccant bag is mounted inside the accumulator canister to absorb any moisture which may have entered and become trapped within the refrigerant system.
REMOVAL
WARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)
(1) Disconnect and isolate the battery negative
cable.
(2) Recover the refrigerant from the refrigerant system. (Refer to 24 - HEATING & AIR CONDI- TIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT RECOVERY)
Fig.15A/CAccumulator
1 - Inner Fender 2 - Line from Accumulator to Evaporator 3 - A/C Line Rentention Clip 4 - Evaporator Ports 5 - Accumulator Mounting Screws 6 - Accumulator 7 - Suction Line 8 - A/C Charging Port 9 - A/C Line Rentention Clip
(3) Loosen the fasteners that secure the accumula- tor and support bracket to the dash panel (Fig. 15). (4) Disconnect the suction line refrigerant line fit- ting from the accumulator outlet. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLERS) Install plugs in, or tape over all of the opened refrig- erant line fittings.
(5) Disconnect the accumulator inlet refrigerant line fitting from the evaporator outlet. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE) Install plugs in, or tape over all of the opened refrigerant line fittings.
(6) Remove the accumulator assembly from the
engine compartment.
PLUMBING
24 - 50
ACCUMULATOR (Continued) INSTALLATIONWARNING: REVIEW THE WARNINGS AND CAU- TIONS IN THE FRONT OF THIS SECTION BEFORE PERFORMING THE FOLLOWING OPERATION. (Refer to 24 - HEATING & AIR CONDITIONING/ PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION)(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAUTION - REFRIGERANT HOSES/LINES/TUBES PRECAUTIONS)
(1) Install the accumulator to the bulkhead but do
not tighten yet.
(2) Remove the tape or plugs from the refrigerant line fittings on the accumulator inlet and the evapo- rator outlet. Connect the accumulator inlet refriger- ant line coupler to the evaporator outlet. (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLERS) (3) Remove the tape or plugs from the refrigerant line fittings on the suction line and the accumulator outlet. Connect the suction line refrigerant line cou- pler to the accumulator outlet. (Refer to 24 - HEAT- ING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - A/C LINE COUPLERS) (4) Tighten the accumulator fasteners to 4.5 N·m(40 in. lbs.).
(5) Connect the battery negative cable. (6) Evacuate the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM EVACUATE)
(7) Charge the refrigerant system. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYS- TEM CHARGE)
DR
through the heater core, heat removed from the engine is transferred to the heater core fins and tubes. Air directed through the heater core picks up the heat from the heater core fins. The blend door allows control of the heater output air temperature by controlling how much of the air flowing through the HVAC housing is directed through the heater core. The blower motor speed controls the volume of air flowing through the HVAC housing.
The heater core cannot be repaired and, if faulty or
damaged, it must be replaced.
REMOVAL
NOTE: Disassembly of the HVAC housing is not required to remove heater core.
(1) Remove the HVAC housing from the vehicle. (Refer to 24 - HEATING & AIR CONDITIONING/ DISTRIBUTION/HVAC HOUSING - REMOVAL)
(2) Remove the screws and retainers that secure
the heater core to the HVAC housing.
(3) Lift the heater core out of the heater-A/C hous-
(4) Inspect all seals and repair or replace as
ing.
required.
INSTALLATION
(1) Place the heater core into the HVAC housing. (2) Snap the retainers for the heater core to the housing. Install and tighten the screws that secure the heater core to the HVAC housing (if equipped). Tighten the screws to 2.2 N·m (20 in. lbs.).
(3) Reinstall the HVAC housing in the vehicle. (Refer to 24 - HEATING & AIR CONDITIONING/ DISTRIBUTION/HVAC HOUSING - INSTALLA- TION)
NOTE: If the accumulator is replaced, add 60 milli- liters (2 fluid ounces) of refrigerant oil to the refrig- erant system. Use only refrigerant oil of the type recommended for the compressor in the vehicle.
REFRIGERANT DESCRIPTION
HEATER CORE DESCRIPTION
The heater core is located in the HVAC housing, under the instrument panel. It is a heat exchanger made of rows of tubes and fins.
The heater core is not repairable and if damaged it
must be replaced.
OPERATION
Engine coolant is circulated through heater hoses to the heater core at all times. As the coolant flows
The refrigerant used in this air conditioning sys- tem is a HydroFluoroCarbon (HFC), type R-134a. Unlike R-12, which is a ChloroFluoroCarbon (CFC), R-134a refrigerant does not contain ozone-depleting chlorine. R-134a refrigerant is a non-toxic, non-flam- mable, clear, and colorless liquefied gas.
Even though R-134a does not contain chlorine, it must be reclaimed and recycled just like CFC-type refrigerants. This is because R-134a is a greenhouse gas and can contribute to global warming.
OPERATION
R-134a refrigerant is not compatible with R-12
refrigerant in an air conditioning system. Even aDR REFRIGERANT (Continued)
small amount of R-12 added to an R-134a refrigerant system will cause compressor failure, refrigerant oil sludge or poor air conditioning system performance. In addition, the PolyAlkylene Glycol (PAG) synthetic refrigerant oils used in an R-134a refrigerant system are not compatible with the mineral-based refriger- ant oils used in an R-12 refrigerant system.
R-134a refrigerant system service ports, service tool couplers and refrigerant dispensing bottles have all been designed with unique fittings to ensure that an R-134a system is not accidentally contaminated with the wrong refrigerant (R-12). There are also labels posted in the engine compartment of the vehi- cle and on the compressor identifying to service tech- nicians that the air conditioning system is equipped with R-134a.
DIAGNOSIS AND TESTING- REFRIGERANT SYSTEM LEAKS
WARNING: (Refer to 24 - HEATING & AIR CONDI- TIONING/PLUMBING - WARNING) and (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAU- TION).
If the air conditioning system does not cool prop- erly, the A/C system performance should be tested. See A/C Performance in the Diagnosis and Testing section of this group for the procedures. If the A/C system refrigerant fill is found to be low or if the sys- tem is empty; a leak at a refrigerant line, connector fitting, component, or component seal is likely.
An electronic leak detector designed for R-134a refrigerant, or a fluorescent R-134a leak detection dye and a black light are recommended for locating and confirming refrigerant system leaks. Refer to the operating instructions supplied by the equipment manufacturer for the proper care and use of this equipment.
An oily residue on or near refrigerant system lines, connector fittings, components, or component seals can indicate the general location of a possible refrig- erant leak. However, the exact leak location should be confirmed with an electronic leak detector prior to component repair or replacement.
To detect a leak in the refrigerant system with an electronic leak detector, perform one of the following procedures:
SYSTEM EMPTY
(1) Evacuate the refrigerant system (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/RE- FRIGERANT - STANDARD PROCEDURE).
(2) Connect and dispense 0.283 kilograms (0.625
pounds or 10 ounces) of R-134a refrigerant into the evacuated refrigerant system (Refer to 24 - HEAT-PLUMBING
24 - 51
ING & AIR CONDITIONING/PLUMBING/REFRIG- ERANT - STANDARD PROCEDURE).
(3) Position the vehicle in a wind-free work area.
This will aid in detecting small leaks.
(4) With the engine not running, use a electronic R-134a leak detector and search for leaks. Because R-134a refrigerant is heavier than air, the leak detec- tor probe should be moved slowly along the bottom side of all refrigerant lines, connector fittings and components.
(5) To inspect the evaporator coil for leaks, insert the electronic leak detector probe into the center instrument panel outlet and the floor duct outlet. Set the blower motor switch to the lowest speed position, and the mode control switch in the recirculation mode (Max-A/C).
SYSTEM LOW
(1) Position the vehicle in a wind-free work area.
This will aid in detecting small leaks.
(2) Bring the refrigerant system up to operating temperature and pressure. This is done by allowing the engine to run with the air conditioning system turned on for five minutes.
(3) With the engine not running, use a electronic R-134a leak detector and search for leaks. Because R-134a refrigerant is heavier than air, the leak detec- tor probe should be moved slowly along the bottom side of all refrigerant lines, connector fittings and components.
(4) To inspect the evaporator coil for leaks, insert the electronic leak detector probe into the center instrument panel outlet and the floor duct outlet. Set the blower motor switch to the lowest speed position, and the mode control switch in the recirculation mode (Max-A/C).
STANDARD PROCEDURE
STANDARD PROCEDURE - REFRIGERANT SYSTEM EVACUATE
WARNING: (Refer to 24 - HEATING & AIR CONDI- TIONING/PLUMBING - WARNING) AND (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAU- TION) BEFORE PERFORMING THE FOLLOWING OPERATION.
If the refrigerant system has been open to the atmosphere, it must be evacuated before the system can be charged. If moisture and air enters the system and becomes mixed with the refrigerant, the com- pressor head pressure will rise above acceptable operating levels. This will reduce the performance of the air conditioner and could damage the compressor. Evacuating the refrigerant system will remove the
PLUMBING
24 - 52
REFRIGERANT (Continued)DR
air and boil the moisture out of the system at near room temperature. To evacuate the refrigerant sys- tem, use the following procedure:
(1) Connect a R-134a refrigerant recovery/recy- cling/charging station that meets SAE Standard J2210 and a manifold gauge set (if required) to the refrigerant system of the vehicle and recover refrig- erant.
(2) Open the low and high side valves and start the charging station vacuum pump. When the suc- tion gauge reads 88 kPa (26 in. Hg.) vacuum or greater, close all of the valves and turn off the vac- uum pump.
(a) If the refrigerant system fails to reach the specified vacuum, the system has a leak that must be corrected. See Refrigerant System Leaks in the Diagnosis and Testing section of this group for the procedures.
(b) If the refrigerant system maintains the spec- ified vacuum for five minutes, restart the vacuum pump, open the suction and discharge valves and evacuate the system for an additional ten minutes. (3) Close all of the valves, and turn off the charg-
ing station vacuum pump.
(4) The refrigerant system is now ready to be charged with R-134a refrigerant(Refer to 24 - HEAT- ING & AIR CONDITIONING/PLUMBING/REFRIG- ERANT - STANDARD PROCEDURE).
STANDARD PROCEDURE- REFRIGERANT RECOVERY
WARNING: (Refer to 24 - HEATING & AIR CONDI- TIONING/PLUMBING - WARNING) AND (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAU- TION) BEFORE PERFORMING THE FOLLOWING OPERATION.
A R-134a refrigerant recovery/recycling/charging station that meets SAE Standard J2210 must be used to recover the refrigerant from an R-134a refrig- erant system. Refer to the operating instructions sup- plied by the equipment manufacturer for the proper care and use of this equipment.
STANDARD PROCEDURE- REFRIGERANT SYSTEM CHARGE
WARNING: (Refer to 24 - HEATING & AIR CONDI- TIONING/PLUMBING - WARNING) AND (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAU- TION) BEFORE PERFORMING THE FOLLOWING OPERATION.
After the refrigerant system has been tested for leaks and evacuated, a refrigerant charge can be
injected into the system. See Refrigerant Charge Capacity in the Service Procedures section of this group for the proper amount of the refrigerant charge, this fill level can also be found on a label attached under the hood of the vehicle..
A R-134a refrigerant recovery/recycling/charging station that meets SAE Standard J2210 must be used to charge the refrigerant system with R-134a refrigerant. Refer to the operating instructions sup- plied by the equipment manufacturer for the proper care and use of this equipment.
this vehicle is:
The R-134a refrigerant system charge capacity for † If equipped with a 3.7L or a 4.7L engine charge † If equipped with a 5.9L engine charge to 0.7371
to 0.6804 Kg. (24 oz.).
Kg. ( 26 oz.).
REFRIGERANT LINE COUPLER DESCRIPTION
Spring-lock type refrigerant line couplers are used to connect many of the refrigerant lines and other components to the refrigerant system. These couplers require a special tool for disengaging the two coupler halves.
OPERATION
The spring-lock coupler is held together by a garter spring inside a circular cage on the male half of the fitting (Fig. 16). When the two coupler halves are connected, the flared end of the female fitting slips behind the garter spring inside the cage on the male fitting. The garter spring and cage prevent the flared end of the female fitting from pulling out of the cage. Three O-rings on the male half of the fitting are used to seal the connection. These O-rings are com- patible with R-134a refrigerant and must be replaced with O-rings made of the same material.
Secondary clips are installed over the two con- nected coupler halves at the factory for added blowoff protection.
REMOVAL
WARNING: (Refer to 24 - HEATING & AIR CONDI- TIONING/PLUMBING - WARNING) (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAU- TION) BEFORE PERFORMING THE FOLLOWING OPERATION.
(1) Recover the refrigerant from the refrigerant system(Refer to 24 - HEATING & AIR CONDITION- ING/PLUMBING/REFRIGERANT STANDARD PROCEDURE).
DR REFRIGERANT LINE COUPLER (Continued)
PLUMBING
24 - 53
Once the garter spring is expanded and while still pushing the disconnect tool into the open side of the coupler cage, pull on the refrigerant line attached to the female half of the coupler fitting until the flange on the female fitting is separated from the garter spring and cage on the male fitting within the dis- connect tool.
NOTE: The garter spring may not release if the A/C line disconnect tool is cocked while pushing it into the coupler cage opening.
Fig.16Spring-LockCoupler-Typical
1 - MALE HALF SPRING-LOCK COUPLER 2 - FEMALE HALF SPRING-LOCK COUPLER 3 - SECONDARY CLIP 4 - CONNECTION INDICATOR RING 5 - COUPLER CAGE 6 - GARTER SPRING 7 - COUPLER CAGE 8 - “O” RINGS
(2) Remove the secondary clip from the spring-lock
coupler.
(3) Fit the proper size A/C line disconnect tool (Special Tool Kit 7193 or equivalent) over the spring- lock coupler cage (Fig. 17).
Fig.17RefrigerantLineSpring-LockCoupler
Disconnect
(4) Close the two halves of the A/C line disconnect
tool around the spring-lock coupler.
(5) Push the A/C line disconnect tool into the open side of the coupler cage to expand the garter spring.
(6) Open and remove the A/C line disconnect tool
from the disconnected spring-lock coupler.
(7) Complete the separation of the two halves of the coupler fitting. Inspect the O-ring seals and mat- ing areas for damage.
INSTALLATION
WARNING: (Refer to 24 - HEATING & AIR CONDI- TIONING/PLUMBING - WARNING) AND (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - CAU- TION) BEFORE PERFORMING THE FOLLOWING OPERATION.
(1) Check to ensure that
the garter spring is located within the cage of the male coupler fitting, and that the garter spring is not damaged.
(a) If the garter spring is missing, install a new spring by pushing it into the coupler cage opening. (b) If the garter spring is damaged, remove it from the coupler cage with a small wire hook (DO NOT use a screwdriver) and install a new garter spring. (2) Clean any dirt or foreign material from both
halves of the coupler fitting.
(3) Install new O-rings on the male half of the cou-
pler fitting.
CAUTION: Use only the specified O-rings as they are made of a special material for the R-134a sys- tem. The use of any other O-rings may allow the connection to leak intermittently during vehicle operation.
(4) Lubricate the male fitting and O-rings, and the inside of the female fitting with clean R-134a refrig- erant oil. Use only refrigerant oil of the type recom- mended for the compressor in the vehicle.
(5) Fit the female half of the coupler fitting over
the male half of the fitting.
(6) Push together firmly on the two halves of the coupler fitting until the garter spring in the cage on the male half of the fitting snaps over the flanged end on the female half of the fitting.
PLUMBING
24 - 54
REFRIGERANT LINE COUPLER (Continued)DR
(7) Ensure that the spring-lock coupler is fully engaged by trying to separate the two coupler halves. This is done by pulling the refrigerant lines on either side of the coupler away from each other.
(8) Reinstall the secondary clip over the spring-
lock coupler cage.
REFRIGERANT OIL DESCRIPTION
The refrigerant oil used in R-134a refrigerant sys- tems is a synthetic-based, PolyAlkylene Glycol (PAG), wax-free lubricant. Mineral-based R-12 refrigerant oils are not compatible with PAG oils, and should never be introduced to an R-134a refrigerant system. There are different PAG oils available, and each contains a different additive package. The SD–7 com- pressor used in this vehicle is designed to use an SP-15 PAG refrigerant oil. Use only refrigerant oil of this same type to service the refrigerant system.
OPERATION
After performing any refrigerant recovery or recy- cling operation, always replenish the refrigerant sys- tem with the same amount of the recommended refrigerant oil as was removed. Too little refrigerant oil can cause compressor damage, and too much can reduce air conditioning system performance.
PAG refrigerant oil is much more hygroscopic than mineral oil, and will absorb any moisture it comes into contact with, even moisture in the air. The PAG oil container should always be kept tightly capped until it is ready to be used. After use, recap the oil container immediately to prevent moisture contami- nation.
STANDARD PROCEDURE - REFRIGERANT OIL LEVEL
When an air conditioning system is assembled at the factory, all components except the compressor are refrigerant oil free. After the refrigerant system has
been charged and operated, the refrigerant oil in the compressor is dispersed throughout the refrigerant system. The accumulator, evaporator, condenser, and compressor will each retain a significant amount of the needed refrigerant oil.
It is important to have the correct amount of oil in the refrigerant system. This ensures proper lubrica- tion of the compressor. Too little oil will result in damage to the compressor. Too much oil will reduce the cooling capacity of the air conditioning system.
It will not be necessary to check the oil level in the compressor or to add oil, unless there has been an oil loss. An oil loss may occur due to a rupture or leak from a refrigerant line, a connector fitting, a compo- nent, or a component seal. If a leak occurs, add 30
milliliters (1 fluid ounce) of refrigerant oil to the refrigerant system after the repair has been made. Refrigerant oil loss will be evident at the leak point by the presence of a wet, shiny surface around the leak.Refrigerant oil must be added when a accumulator, evaporator coil or condenser are replaced. See the Refrigerant Oil Capacities chart. When a compressor is replaced, the refrigerant oil must be drained from the old compressor and measured. Drain all of the refrigerant oil from the new compressor, then fill the new compressor with the same amount of refrigerant oil that was drained out of the old compressor.
Refrigerant Oil Capacities
Component
Complete A/C System
Accumulator Condenser Evaporator
Compressor
fl oz
ml 180
60
30
60drain and measure the oil from the old compressor - see text.
DR
EMISSIONS CONTROL
25 - 1
EMISSIONS CONTROL
TABLE OF CONTENTS
page
page
EMISSIONS CONTROL
DESCRIPTION
DESCRIPTION - STATE DISPLAY TEST
DESCRIPTION - MONITORED SYSTEMS . . . . 1
DESCRIPTION - TRIP DEFINITION . . . . . . . . . 4
. . 4
DESCRIPTION - COMPONENT MONITORSMODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
OPERATION
DESCRIPTION - CIRCUIT ACTUATION TEST
MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DESCRIPTION - DIAGNOSTIC TROUBLE
CODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DESCRIPTION - TASK MANAGER . . . . . . . . . . 1OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . 4
OPERATION - TASK MANAGER . . . . . . . . . . . 5
OPERATION - NON-MONITORED CIRCUITS . . 8
. . . . . . . . . . . . . . . . 10EVAPORATIVE EMISSIONS
EMISSIONS CONTROL
DESCRIPTION
DESCRIPTION - STATE DISPLAY TEST MODE
The switch inputs to the Powertrain Control Mod- ule (PCM) have two recognized states; HIGH and LOW. For this reason, the PCM cannot recognize the difference between a selected switch position versus an open circuit, a short circuit, or a defective switch. If the State Display screen shows the change from HIGH to LOW or LOW to HIGH, assume the entire switch circuit to the PCM functions properly. Connect the DRB scan tool to the data link connector and access the state display screen. Then access either State Display Inputs and Outputs or State Display Sensors.
DESCRIPTION - CIRCUIT ACTUATION TEST MODE
The Circuit Actuation Test Mode checks for proper operation of output circuits or devices the Powertrain Control Module (PCM) may not internally recognize. The PCM attempts to activate these outputs and allow an observer to verify proper operation. Most of the tests provide an audible or visual indication of device operation (click of relay contacts, fuel spray, etc.). Except for intermittent conditions, if a device functions properly during testing, assume the device, its associated wiring, and driver circuit work cor- rectly. Connect the DRB scan tool to the data link connector and access the Actuators screen.
A Diagnostic Trouble Code (DTC)
DESCRIPTION - DIAGNOSTIC TROUBLE CODES indicates the PCM has recognized an abnormal condition in the system.
Remember that DTC’s are the results of a sys- tem or circuit failure, but do not directly iden- tify the failed component or components.
BULB CHECK
Each time the ignition key is turned to the ON position, the malfunction indicator (check engine) lamp on the instrument panel should illuminate for approximately 2 seconds then go out. This is done for a bulb check.
OBTAINING DTC’S USING DRB SCAN TOOL
(1) Obtain the applicable Powertrain Diagnostic
Manual.
(2) Obtain the DRB Scan Tool. (3) Connect the DRB Scan Tool to the data link (diagnostic) connector. This connector is located in the passenger compartment; at the lower edge of instrument panel; near the steering column.
(4) Turn the ignition switch on and access the
“Read Fault” screen.
(5) Record all the DTC’s and “freeze frame” infor-
mation shown on the DRB scan tool.
(6) To erase DTC’s, use the “Erase Trouble Code” data screen on the DRB scan tool. Do not erase any DTC’s until problems have been investigated and repairs have been performed.
DESCRIPTION - TASK MANAGER
The PCM is responsible for efficiently coordinating the operation of all the emissions-related compo- nents. The PCM is also responsible for determining if the diagnostic systems are operating properly. The software designed to carry out these responsibilities is call the ’Task Manager’.
DESCRIPTION - MONITORED SYSTEMS
There are new electronic circuit monitors that check fuel, emission, engine and ignition perfor-
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EMISSIONS CONTROL (Continued)mance. These monitors use information from various sensor circuits to indicate the overall operation of the fuel, engine, ignition and emission systems and thus the emissions performance of the vehicle.
The fuel, engine,
ignition and emission systems monitors do not indicate a specific component prob- lem. They do indicate that there is an implied prob- lem within one of the systems and that a specific problem must be diagnosed.
If any of these monitors detect a problem affecting vehicle emissions, the Malfunction Indicator Lamp (MIL) will be illuminated. These monitors generate Diagnostic Trouble Codes that can be displayed with the MIL or a scan tool. The following is a list of the system monitors: † Misfire Monitor † Fuel System Monitor † Oxygen Sensor Monitor † Oxygen Sensor Heater Monitor † Catalyst Monitor † Leak Detection Pump Monitor (if equipped) All these system monitors require two consecutive
trips with the malfunction present to set a fault.
Refer to the appropriate Powertrain Diagnos- tics Procedures manual for diagnostic proce- dures.
The following is an operation and description of
each system monitor :
OXYGEN SENSOR (O2S) MONITOR
Effective control of exhaust emissions is achieved by an oxygen feedback system. The most important element of the feedback system is the O2S. The O2S is located in the exhaust path. Once it reaches oper- ating temperature 300° to 350°C (572° to 662°F), the sensor generates a voltage that is inversely propor- tional to the amount of oxygen in the exhaust. The information obtained by the sensor is used to calcu- late the fuel injector pulse width. This maintains a 14.7 to 1 Air Fuel (A/F) ratio. At this mixture ratio, the catalyst works best to remove hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxide (NOx) from the exhaust.
The O2S is also the main sensing element for the
Catalyst and Fuel Monitors.
manners:
The O2S can fail in any or all of the following † slow response rate † reduced output voltage † dynamic shift † shorted or open circuits Response rate is the time required for the sensor to switch from lean to rich once it is exposed to a richer than optimum A/F mixture or vice versa. As the sen- sor starts malfunctioning, it could take longer to
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detect the changes in the oxygen content of the exhaust gas.
The output voltage of the O2S ranges from 0 to 1
volt. A good sensor can easily generate any output voltage in this range as it is exposed to different con- centrations of oxygen. To detect a shift in the A/F mixture (lean or rich), the output voltage has to change beyond a threshold value. A malfunctioning sensor could have difficulty changing beyond the threshold value.OXYGEN SENSOR HEATER MONITOR
If there is an oxygen sensor (O2S) shorted to volt- age DTC, as well as a O2S heater DTC, the O2S fault MUST be repaired first. Before checking the O2S fault, verify that the heater circuit is operating correctly.
Effective control of exhaust emissions is achieved by an oxygen feedback system. The most important element of the feedback system is the O2S. The O2S is located in the exhaust path. Once it reaches oper- ating temperature 300° to 350°C (572 ° to 662°F), the sensor generates a voltage that is inversely propor- tional to the amount of oxygen in the exhaust. The information obtained by the sensor is used to calcu- late the fuel injector pulse width. This maintains a 14.7 to 1 Air Fuel (A/F) ratio. At this mixture ratio, the catalyst works best to remove hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxide (NOx) from the exhaust.
The voltage readings taken from the O2S sensor are very temperature sensitive. The readings are not accurate below 300°C. Heating of the O2S sensor is done to allow the engine controller to shift to closed loop control as soon as possible. The heating element used to heat the O2S sensor must be tested to ensure that it is heating the sensor properly.
The O2S sensor circuit is monitored for a drop in voltage. The sensor output is used to test the heater by isolating the effect of the heater element on the O2S sensor output voltage from the other effects.
LEAK DETECTION PUMP MONITOR (IF EQUIPPED) The leak detection assembly incorporates two pri- mary functions: it must detect a leak in the evapora- tive system and seal the evaporative system so the leak detection test can be run.
The primary components within the assembly are: A three port solenoid that activates both of the func- tions listed above; a pump which contains a switch, two check valves and a spring/diaphragm, a canister vent valve (CVV) seal which contains a spring loaded vent seal valve.
Immediately after a cold start, between predeter- mined temperature thresholds limits, the three port solenoid is briefly energized. This initializes the
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pump by drawing air into the pump cavity and also closes the vent seal. During non test conditions the vent seal is held open by the pump diaphragm assembly which pushes it open at the full travel posi- tion. The vent seal will remain closed while the pump is cycling due to the reed switch triggering of the three port solenoid that prevents the diaphragm assembly from reaching full travel. After the brief initialization period, the solenoid is de-energized allowing atmospheric pressure to enter the pump cavity, thus permitting the spring to drive the dia- phragm which forces air out of the pump cavity and into the vent system. When the solenoid is energized and de energized, the cycle is repeated creating flow in typical diaphragm pump fashion. The pump is con- trolled in 2 modes:
Pump Mode: The pump is cycled at a fixed rate to achieve a rapid pressure build in order to shorten the overall test length.
Test Mode: The solenoid is energized with a fixed duration pulse. Subsequent fixed pulses occur when the diaphragm reaches the Switch closure point.
The spring in the pump is set so that the system will achieve an equalized pressure of about 7.5” H20. The cycle rate of pump strokes is quite rapid as the system begins to pump up to this pressure. As the pressure increases, the cycle rate starts to drop off. If there is no leak in the system, the pump would even- tually stop pumping at the equalized pressure. If there is a leak, it will continue to pump at a rate rep- resentative of the flow characteristic of the size of the leak. From this information we can determine if the leak is larger than the required detection limit (cur- rently set at .040” orifice by CARB). If a leak is revealed during the leak test portion of the test, the test is terminated at the end of the test mode and no further system checks will be performed.
After passing the leak detection phase of the test, system pressure is maintained by turning on the LDP’s solenoid until the purge system is activated. Purge activation in effect creates a leak. The cycle rate is again interrogated and when it increases due to the flow through the purge system, the leak check portion of the diagnostic is complete.
The canister vent valve will unseal the system after completion of the test sequence as the pump diaphragm assembly moves to the full travel position. Evaporative system functionality will be verified by using the stricter evap purge flow monitor. At an appropriate warm idle the LDP will be energized to seal the canister vent. The purge flow will be clocked up from some small value in an attempt to see a shift in the 02 control system. If fuel vapor, indicated by a shift in the 02 control, is present the test is passed. If not, it is assumed that the purge system is
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not functioning in some respect. The LDP is again turned off and the test is ended.
MISFIRE MONITOR
Excessive engine misfire results in increased cata- lyst temperature and causes an increase in HC emis- sions. Severe misfires could cause catalyst damage. To prevent catalytic convertor damage, the PCM monitors engine misfire.
The Powertrain Control Module (PCM) monitors for misfire during most engine operating conditions (positive torque) by looking at changes in the crank- shaft speed. If a misfire occurs the speed of the crankshaft will vary more than normal.
FUEL SYSTEM MONITOR
To comply with clean air regulations, vehicles are equipped with catalytic converters. These converters reduce the emission of hydrocarbons, oxides of nitro- gen and carbon monoxide. The catalyst works best when the Air Fuel (A/F) ratio is at or near the opti- mum of 14.7 to 1.
The PCM is programmed to maintain the optimum air/fuel ratio of 14.7 to 1. This is done by making short term corrections in the fuel injector pulse width based on the O2S sensor output. The programmed memory acts as a self calibration tool that the engine controller uses to compensate for variations in engine specifications, sensor tolerances and engine fatigue over the life span of the engine. By monitoring the actual fuel-air ratio with the O2S sensor (short term) and multiplying that with the program long-term (adaptive) memory and comparing that to the limit, it can be determined whether it will pass an emis- sions test. If a malfunction occurs such that the PCM cannot maintain the optimum A/F ratio, then the MIL will be illuminated.
CATALYST MONITOR
To comply with clean air regulations, vehicles are equipped with catalytic converters. These converters reduce the emission of hydrocarbons, oxides of nitro- gen and carbon monoxide.
Normal vehicle miles or engine misfire can cause a catalyst to decay. This can increase vehicle emissions and deteriorate engine performance, driveability and fuel economy.
The catalyst monitor uses dual oxygen sensors (O2S’s) to monitor the efficiency of the converter. The dual O2S’s sensor strategy is based on the fact that as a catalyst deteriorates, its oxygen storage capacity and its efficiency are both reduced. By monitoring the oxygen storage capacity of a catalyst, its effi- ciency can be indirectly calculated. The upstream O2S is used to detect the amount of oxygen in the exhaust gas before the gas enters the catalytic con-
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EMISSIONS CONTROL (Continued)verter. The PCM calculates the A/F mixture from the output of the O2S. A low voltage indicates high oxy- gen content (lean mixture). A high voltage indicates a low content of oxygen (rich mixture).
When the upstream O2S detects a lean condition, there is an abundance of oxygen in the exhaust gas. A functioning converter would store this oxygen so it can use it for the oxidation of HC and CO. As the converter absorbs the oxygen, there will be a lack of oxygen downstream of the converter. The output of the downstream O2S will indicate limited activity in this condition.
As the converter loses the ability to store oxygen, the condition can be detected from the behavior of the downstream O2S. When the efficiency drops, no chemical reaction takes place. This means the con- centration of oxygen will be the same downstream as upstream. The output voltage of the downstream O2S copies the voltage of the upstream sensor. The only difference is a time lag (seen by the PCM) between the switching of the O2S’s.
To monitor the system, the number of lean-to-rich switches of upstream and downstream O2S’s is counted. The ratio of downstream switches to upstream switches is used to determine whether the catalyst is operating properly. An effective catalyst will have fewer downstream switches than it has upstream switches i.e., a ratio closer to zero. For a totally ineffective catalyst, this ratio will be one-to- one, indicating that no oxidation occurs in the device. The system must be monitored so that when cata- lyst efficiency deteriorates and exhaust emissions increase to over the legal limit, the MIL will be illu- minated.
DESCRIPTION - TRIP DEFINITION
The term “Trip” has different meanings depending on what the circumstances are. If the MIL (Malfunc- tion Indicator Lamp) is OFF, a Trip is defined as when the Oxygen Sensor Monitor and the Catalyst Monitor have been completed in the same drive cycle. When any Emission DTC is set, the MIL on the dash is turned ON. When the MIL is ON, it takes 3
good trips to turn the MIL OFF. In this case, it depends on what type of DTC is set to know what a “Trip” is.For the Fuel Monitor or Mis-Fire Monitor (contin- uous monitor), the vehicle must be operated in the “Similar Condition Window” for a specified amount of time to be considered a Good Trip.
If a Non-Contiuous OBDII Monitor fails twice in a row and turns ON the MIL, re-running that monitor which previously failed, on the next start-up and passing the monitor, is considered to be a Good Trip. These will include the following:
† Oxygen Sensor
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† Catalyst Monitor † Purge Flow Monitor † Leak Detection Pump Monitor (if equipped) † EGR Monitor (if equipped) † Oxygen Sensor Heater Monitor If any other Emission DTC is set (not an OBDII Monitor), a Good Trip is considered to be when the Oxygen Sensor Monitor and Catalyst Monitor have been completed; or 2 Minutes of engine run time if the Oxygen Sensor Monitor or Catalyst Monitor have been stopped from running.
It can take up to 2 Failures in a row to turn on the MIL. After the MIL is ON, it takes 3 Good Trips to turn the MIL OFF. After the MIL is OFF, the PCM will self-erase the DTC after 40 Warm-up cycles. A Warm-up cycle is counted when the ECT (Engine Coolant Temperature Sensor) has crossed 160°F and has risen by at least 40°F since the engine has been started.
DESCRIPTION - COMPONENT MONITORS
There are several components that will affect vehi- cle emissions if they malfunction. If one of these com- ponents malfunctions the Malfunction Indicator Lamp (MIL) will illuminate.
Some of the component monitors are checking for proper operation of the part. Electrically operated components now have input (rationality) and output (functionality) checks. Previously, a component like the Throttle Position sensor (TPS) was checked by the PCM for an open or shorted circuit. If one of these conditions occurred, a DTC was set. Now there is a check to ensure that the component is working. This is done by watching for a TPS indication of a greater or lesser throttle opening than MAP and engine rpm indicate. In the case of the TPS, if engine vacuum is high and engine rpm is 1600 or greater, and the TPS indicates a large throttle opening, a DTC will be set. The same applies to low vacuum if the TPS indicates a small throttle opening.
All open/short circuit checks, or any component that has an associated limp-in, will set a fault after 1
trip with the malfunction present. Components with- out an associated limp-in will take two trips to illu- minate the MIL.OPERATION
OPERATION
The Powertrain Control Module (PCM) monitors many different circuits in the fuel injection, ignition, emission and engine systems. If the PCM senses a problem with a monitored circuit often enough to indicate an actual problem, it stores a Diagnostic Trouble Code (DTC) in the PCM’s memory. If the
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problem is repaired or ceases to exist, the PCM can- cels the code after 40 warm-up cycles. Diagnostic trouble codes that affect vehicle emissions illuminate the Malfunction Indicator Lamp (MIL). The MIL is displayed as an engine icon (graphic) on the instru- ment panel. Refer to Malfunction Indicator Lamp in this section.
Certain criteria must be met before the PCM stores a DTC in memory. The criteria may be a spe- cific range of engine RPM, engine temperature, and/or input voltage to the PCM.
The PCM might not store a DTC for a monitored circuit even though a malfunction has occurred. This may happen because one of the DTC criteria for the circuit has not been met. For example, assume the diagnostic trouble code criteria requires the PCM to monitor the circuit only when the engine operates between 750 and 2000 RPM. Suppose the sensor’s output circuit shorts to ground when engine operates above 2400 RPM (resulting in 0 volt input to the PCM). Because the condition happens at an engine speed above the maximum threshold (2000 rpm), the PCM will not store a DTC.
There are several operating conditions for which the PCM monitors and sets DTC’s. Refer to Moni- tored Systems, Components, and Non-Monitored Cir- cuits in this section.
Technicians must retrieve stored DTC’s by connect- ing the DRB scan tool (or an equivalent scan tool) to the 16–way data link connector. The connector is located on the bottom edge of the instrument panel near the steering column (Fig. 1).
