TB3 - Diagnostic Trouble Codes 97, 623 and 631

Diagnostic Trouble Code (DTC) 97, 623 and 631 indicates a transmission control light circuit concern (observed during Key On Engine Off (KOEO) Self-Test).

Possible Causes:
- Burned out bulb.
- Shorted harness.
- Open harness fuse.

- Was the Transmission Control Switch (TCS) cycled during Key On Engine Off (KOEO) Self-Test?

Yes -- Go to TB5. TB5 - Check Harness Circuit(s) For Short to Ground

No -- Rerun KOEO Self-Test cycling the TCS. Quick Test Appendix (Detailed Testing Instructions)