P1634

P1634-TCM INTERNAL-INTERNAL WATCHDOG PERFORMANCE





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.

Possible Causes
TRANSMISSION CONTROL MODULE

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

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. Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test