PCM - A/C Does Not Cool
NO: 24-03-96GROUP: Air Conditioning
DATE: Feb. 23, 1996
SUBJECT:
A/C Does Not Cool
MODELS:
1996 (AB) Ram Van/Wagon
1996 (AN) Dakota
1996 (BR) Ram Truck
1996 (ZJ) Grand Cherokee
NOTE: THIS BULLETIN AFFECTS VEHICLES EQUIPPED WITH A 5.2L, 5.9L (GAS ENGINE ONLY), OR 8.0L ENGINES ONLY.
SYMPTOM/CONDITION:
Customers complaints of lack of cooling may be related to a condition where the A/C clutch either remains engaged at Wide Open Throttle (WOT) or remains disengaged after a WOT operation.
NOTE: THIS CONDITION OCCURS ONLY AT ENGINE SPEEDS OF APPROXIMATELY 3000 RPM.
This condition could cause the A/C evaporator to freeze up or may cause the compressor to not circulate refrigerant through the A/C system. This condition could be caused by the PCM leaving the A/C clutch relay energized or de-energized too long.
DIAGNOSIS:
Using the Mopar Diagnostic System (MDS) or the Scan Tool (DRBIII) and appropriate Diagnostic Procedure Manual, verify that all engine systems are functioning correctly. If Diagnostic Trouble Codes (DTC's) are present, record them on the repair order for future reference and repair as necessary. If the above condition exists, perform the repair procedure.
EQUIPMENT/PARTS REQUIRED:
1 CH6000 Scan Tool (DRBIII )
1 CH7035 General Purpose Interface Bus Cable (GPIB)
1 CH7000 J1962 Cable
1 4669020 Label - Authorized Software Update
1 4275086 Label - Authorized Modification
REPAIR PROCEDURE:
This bulletin involves selectively erasing and reprogramming the Powertrain Control Module (PCM) with new software (calibration change).
NOTE: MDS AND DRBIII ARE REQUIRED TO PERFORM THE FOLLOWING REPAIR. MDS MUST BE OPERATING WITH RELEASE 19 OR HIGHER AND TIL 1101 OR HIGHER INSTALLED.
1. Connect the MDS and DRBIII to the vehicle and power them up.
2. Use the arrow keys and select # 2 MDS DIAGNOSTICS on the DRBIII MAIN MENU Screen.
3. Use the arrow keys and select DIAGNOSTIC MENU on the MDS, then press NEXT MENU.
4. Use the arrow keys and select CONTROLLER PROGRAMMING on the MDS, then press NEXT MENU.
5. Use the arrow keys and select PROGRAM VEHICLE CONTROLLER on the MDS, then press NEXT MENU.
6. Follow the steps presented on the MDS and DRBIII which will allow the DRBIII to obtain the current part number of the PCM.
7. The MDS will display the part number of the PCM on the vehicle and the appropriate replacement part number, then press NEXT MENU to begin programming.
If the PCM on the vehicle has already been updated or programmed, a NO UPDATES AVAILABLE message will be displayed. Check the part number of the PCM on the vehicle and compare it to the part number displayed. If the PCM has already been updated, then a system problem actually exists and should be corrected.
8. The MDS and DRBIII will prompt the operator for any action needed during the remainder of the programming process.
NOTE: YOU MAY BE REQUIRED TO REPROGRAM THE VIN AND ALL OPTIONS INTO THE UPDATED PCM. THIS WOULD BE THE SAME PROCEDURE THAT YOU WOULD USE IF YOU ARE INSTALLING A NEW PCM.
NOTE: THE FOLLOWING STEPS ARE REQUIRED BY LAW.
9. Type the necessary information on the Authorized Software Update" label, P/N 4669020. Attach the label to the PCM and cover the label with the clear plastic overlay.
10. Type the necessary information on the Authorized Modification Label and attach the label near the VECI Label.
POLICY: Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
Labor Operation No: Reprogram Powertrain Control Module
08-19-44-98 0.5 Hrs.
FAILURE CODE: FM - Flash Module