Symptoms/Condition: Shifter reports loss communication AND NO OTHER MODULES report the condition

Bulletin number

9100641

Component

Power train

Summary

Symptoms/Condition: Shifter reports loss communication AND NO OTHER MODULES report the condition. Diagnostic: Please make sure ONLY shifter reports loss communication. If there are other modules reporting loss communication, then follow the existing service procedure Repair Procedure: 1. Verify Complaint - ESM reports a Loss of Communication (LOC) DTC, but no other modules do. - If multiple modules report the same LOC, the ESM is not the cause (its not a gateway module). 2. Read DTCs - Relevant codes: U0101, U0140, U0155, U0129, U11C3, U0402, U0422, U0423, U0415, U145D. - If multiple LOC DTCs are present: a. Check battery health, system voltage, and TCM (including valve body). b. If TCM goes offline, ESM may falsely report LOC DTCs. 3. Check Environmental Data - Look for voltage/system issues at the same mileage. a. If DTCs clear, do not replace ESM. b. If not, inspect: b.1 Module connectors/pins: If damaged, dont repair shifter. b.2 TCM connectors/pins: Same rule. b.3 AGSM connectors/pins: If damaged, repair shifter. b.4 AGSM wiring harness: If damaged, dont repair shifter. 4. Review Past Service - Confirm battery and TCM-related repairs are still effective. a. If not, fix and clear DTCs. b. If yes, continue. 5. Check for Other LOCs - If other modules report LOC to the same module, inspect that module. - If not, repair the AGSM. Additional Description: - The ESM only communicates with the TCM and is fully controlled by it. - In non-combustion engines, the TCM is replaced by the PCM. - If a stored DTC in the ESM disappears and doest return, do not replace the ESM.

Owners of these vehicles have filed 98 complaints in the transmission category.