P1634

P1634-TCM INTERNAL- INTERNAL WATCHDOG PERFORMANCE





For a complete wiring diagram Consult Diagrams/Electrical

Theory of Operation

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

- When Monitored:
Continuously with the ignition on.

- Set Condition:
If the TCM microprocessor internal watchdog detects an error.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview

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 and program the TCM.
- Perform NAG1 TRANSMISSION VERIFICATION TEST.Verification Tests