P1636

P1636-TCM INTERNAL- EXTERNAL WATCHDOG PERFORMANCE





For a complete wiring diagram, refer to the Wiring Information.

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.





Always perform the NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding Initial Inspection and Diagnostic Overview.
TRANSMISSION CONTROL MODULE

Repair

- Using the schematics as a guide, check the Transmission Control Module (TCM) connectors and terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the TCM.
- Perform NAG1 TRANSMISSION VERIFICATION TEST NAG1 Transmission Verification Test.