OBD with Scan Tool

These self-tests should be used to diagnose the TCM and should be carried out in order.

1. If the cause is not visually evident, connect the scan tool to the DLC.
   NOTE: The VCM LED prove-out confirms power and ground from the DLC to the VCM.
2. If the scan tool does not communicate with the VCM:
   • check the VCM connection to the vehicle.
   • check the scan tool connection to the VCM.
   • refer to MODULE COMMUNICATIONS NETWORK to diagnose no power to the scan tool.
3. If the scan tool does not communicate with the vehicle:
   • verify the ignition is in the RUN position.
   • verify scan tool operation with a known good vehicle.
   • refer to MODULE COMMUNICATIONS NETWORK to diagnose no response from the TCM.
4. Carry out the network test.
   • If the scan tool responds with no communication from one or more modules, refer to MODULE COMMUNICATIONS NETWORK .
   • If the network test passes, retrieve and record the continuous memory DTCs.
5. Clear the continuous DTCs and carry out the TCM self-test.
6. If DTCs retrieved are related to the concern, GO to the DTC Chart .
7. If no DTCs related to the concern are retrieved, GO to DIAGNOSIS BY SYMPTOM .