Diagnostic Trouble Code (DTC) Information

Condition







The solenoids are controlled by power stages in the transmission control module (TCM). The transmission control module (TCM) opens the power stages when to activate the solenoids and sends a voltage through the circuit. Diagnostic trouble code (DTC) TCM-0120, TCM-0121, TCM-0122, TCM-0123 or TCM-0124 is stored (depending on the power stage) if the transmission control module (TCM) registers an internal fault in the power stage circuit for solenoids S1, S2, S3, S4, S5, SLU, SLT, or SLS.

Substitute value
- Transmission control module (TCM) "Limp-Home" program initiated.

Possible source
- Internal fault in the control module.

Fault symptom[s]
- The warning lamp for the automatic transmission flashes.
- Malfunction indicator light (MIL) lit.
- No lock-up function.
- Harsh gear shifting.
- No shifting.

HINT:
- Harsh gear shifting can be caused by:
- No reduction of the line pressure when shifting.
- No request for torque limiting to the engine control module (ECM) when shifting.

No shifting because the transmission module (TCM) prevents activation of the solenoids.