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 controllers 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 NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding. Component Tests and General Diagnostics

Diagnostic Test
1. TRANSMISSION CONTROL MODULE
View repair
Repair
Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the TCM. Refer to Body Control Systems for diagnostic procedures and for further possible causes. Testing and Inspection
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1. Transmission Verification Test