P1636-TCM INTERNAL- EXTERNAL WATCHDOG PERFORMANCE

For a complete wiring diagram Refer to Section 8W

Theory of Operation

The Transmission Control Module (TCM) performs various internal tests to verify proper controller operation. This DTC indicates that watch dog circuitry external to the microprocessor has detected an error. If the TCM watch dog circuitry external to the microprocessor detects an error, the controller will enter Limp-in mode and illuminate the MIL.

When Monitored:
Continuously with the ignition on.
Set Condition:
If the TCM watch dog circuitry external to the microprocessor detects an error.

Possible Causes

TRANSMISSION CONTROL MODULE

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)

Diagnostic Test

1. TRANSMISSION CONTROL MODULE

View repair

Repair

Using the schematics as a guide, check the Transmission Control Module (TCM) pins, terminals, and connectors for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the TCM per the Service Information. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/TRANSMISSION CONTROL MODULE - REMOVAL)
Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)