A/T Controls - Power Reduction In Cold Temperatures
Bulletin No: 05-003/09Last Issued: 01/29/2009
Subject:
SUDDEN REDUCTION OF POWER AT HIGHWAY SPEEDS IN EXTREMELY COLD AMBIENT TEMPERATURES
BULLETIN NOTE
APPLICABLE MODEL(S)/VINS
DESCRIPTION
Some vehicles may experience a sudden reduction of power after being driven continuously in extremely cold ambient temperatures (5°F {-15°C}) for long periods of time (Ex. 1 hour or longer, but is dependant on ambient temperatures) without a key off cycle.
When the vehicle is driven in these conditions, the ATX oil flow through the oil cooler is limited by the increased oil viscosity and cannot be sufficiently cooled. When the oil temperature exceeds 338°F (170°C), the Transmission Control Module (TCM) requests a decrease in engine torque to protect the ATX against over-heating.
This condition occurs without the MIL illuminating, DTCs, or FFD data being stored. The condition can be temporarily corrected by pulling over to the side of the road and turning the engine off and restarting it.
The TCM logic has changed to reduce the occurrence of decrease in engine torque by requesting the ATX to go into lock-up to reduce the ATX oil temperature.
Customers having this concern should have their vehicle repaired using the following repair procedure.
REPAIR PROCEDURE
1. Reboot the IDS to clear memory before reprogramming.
2. Using IDS B52.10 or later software, reprogram the TCM to the latest calibration (refer to "Calibration Information" table) by following the "Module Reprogramming" procedure.
CAUTION:
During the reprogramming procedure, a message on the screen will appear asking if you are repairing an applicable vehicle or not. It may cause a customer driving feel complaint if the "YES" button is selected for a vehicle that is NOT applicable.
NOTE:
^ Always update the IDS tool first, then follow on-screen instructions to download the needed calibration file for TCM reprogramming.
^ It is not necessary to remove any fuses or relays during TCM reprogramming when the IDS screen prompts you to do so. You may accidentally stop power to one of the TCM terminals and cause the TCM to be blanked, or you may receive error messages during the IDS reprogramming procedure.
^ IDS shows the calibration part numbers after programming the TCM.
^ Please be aware that TCM calibration part numbers and file names listed in any Service Bulletin may change due to future releases of IDS software, and additional revisions made to those calibrations for service related concerns.
^ When reprogramming a TCM, IDS will always display the "latest" calibration P/N available for that vehicle. If any calibration has been revised/updated to contain new information for a new service concern/issue, it will also contain all previously released calibrations.
^ When performing this procedure, we recommend that a battery charger be installed on the vehicle battery and turned ON to a maximum charge of no more than 20 AMPS to keep the vehicle battery up to capacity. If you exceed 20 AMPS, it could damage the VCM.
3. After performing the TCM reprogramming procedure, verify the repair by starting the engine and making sure there are no MIL illumination or abnormal warning lights present.
NOTE:
^ If any DTCs should remain after performing DTC erase, diagnose the DTCs according to the appropriate Troubleshooting section of the Workshop Manual.
^ After TCM reprogramming, it is no longer necessary to road test the vehicle to "relearn" KAM (Keep Alive Memory).
4. In addition to reprogramming the TCM, replace the thermo valve with a minimum flow spec. thermo valve according to Workshop Manual (section 05-17 OIL COOLER REMOVAL/INSTALLATION [AW6A-EL, AW6AX-EL]).
CALIBRATION INFORMATION
PART(S) INFORMATION
WARRANTY INFORMATION