P1634-TCM INTERNAL-INTERNAL 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 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 NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Transmission Control (TCM) - Standard Procedure).

• 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 in accordance with the Service Information.
• Perform the NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Transmission Control (TCM) - Standard Procedure).