TCM - Erroneous DTC A4/Actuator Tests Not Functioning
NO: 21-07-96GROUP: Transmission
DATE: May 3, 1996
SUBJECT:
Erroneous DTC A4 And DRB III Transmission Actuator Test Corrected
MODELS:
1996 (AB) Ram Van/Wagon
1996 (AN) Dakota
1996 (BR) Ram Truck
1996 (ZJ) Grand Cherokee
NOTE:
THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH AUTOMATIC TRANSMISSIONS ONLY.
SYMPTOM/CONDITION:
When diagnosing a vehicle utilizing the Mopar Diagnostic System (MDS)/Scan Tool (DRBIII) DTC HEX A4 (Trans Temp Sensor No Temp Rise After Start - MIL 37) may be encountered. Also the DRBIII/MDS may not be able to perform the "Actuator Test" for the Torque Converter Clutch (TCC) solenoid properly.
DISCUSSION:
The Powertrain Control Module (PCM) logic may set DTC HEX A4 without a malfunctioning transmission temperature sensor. The transmission temperature sensor is an input to the PCM to aid in controlling the operation of the TCC. when the transmission temperature sensor fails and DTC HEX A4 is set the PCM will rely on information from the Engine Coolant Temperature (ECT) sensor to control TCC operation. Due to the PCM using the ECT sensor as a back-up sensor our customers will not complain of any malfunction of the TCC operation even with a failed transmission temperature sensor nor will the Check Engine Lamp (MIL) illuminate.
In addition the test designed to identify TCC malfunctions utilizing the DRBIII/MDS function called Actuator Tests" does not function properly due to software problems within the PCM. The test was designed to set governor pressure to a maximum level and duty cycle the TCC solenoid. This would allow the technician to check hydraulic pressure of the TCC circuit without having to drive the vehicle. Because of a software malfunction in the PCM the PCM would not initiate the governor pressure solenoid during the test, thus requiring the vehicle to be driven for testing.
Please perform updates to the PCM for any vehicle listed that you encounter. The update will correct both conditions
DIAGNOSIS:
Using the MDS or the DRBIII and appropriate Diagnostic Procedure Manual verify that all engine systems are functioning correctly. If Diagnostic Trouble Codes (DTCs) are present record them on the repair order for future reference and repair before proceeding with this bulletin
NOTE:
IT IS NOT NECESSARY TO ALSO UPDATE THE PCM FOR CONDITIONS LISTED IN TSB 24-03-96 DATED FEB. 23, 1996, 08-07-96 DATED MARCH 8, 1996, OR 18-03-96 REV. B DATED APRIL 19, 1996. PCM UPDATES PERFORMED WITH RELEASE 19 AND TIL 1105 WILL UPDATE THE SOFTWARE TO THE MOST RECENT LEVEL AND INCLUDE ALL PREVIOUS REVISIONS.
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 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 1105 OR HIGHER INSTALLED.
1. Connect the MDS to the DRBIII and connect the DRBIII to the vehicle 16-way Data Link Connector (DLC) 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 VEHICLE CONTROLLER PROGRAMMING on the MDS7 then press NEXT MENU.
5. Use the arrow keys and select PROGRAMMING OF ALL OTHER CONTROLLERS WITH MDS AND DRBIII 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:
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
08-19-50-92 0.5 Hrs.
FAILURE CODE: FM - Flash Module