P1633

P1633-TCM INTERNAL - TEST EXTERNAL WATCHDOG PERFORMANCE





Theory of Operation
The Transmission Control Module (TCM) performs various internal tests to verify proper controller operation. This DTC indicates that there is an issue with the TCM's external watchdog. If the TCM detects an error with the controllers external watchdog failed the power up test, the controller will enter Limp-in mode and illuminate the MIL.
- When Monitored:
Continuously with the ignition on.
- Set Condition:
If the TCM detects an error with the controllers external watchdog failed the power up test.

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