P0742 Fault Code in Honda: Causes, Symptoms, and Fixes

DTC P0742 means the Torque Converter Clutch (TCC) is stuck in the “ON” position, meaning it is locked when it shouldn’t be. The Transmission Control Module (TCM) expects the torque converter to unlock during certain conditions (like idling or low speeds), but it detects it remains engaged. This can stall the engine, cause harsh driving conditions, and increase wear on transmission components.

Symptoms:

1. Check Engine Light (CEL)
2. Engine stalls when coming to a stop
3. Harsh or delayed shifting
4. Jerking during deceleration
5. Reduced fuel economy
6. Vehicle may enter limp mode

Common Causes:

1. TCC solenoid stuck closed
2. Wiring short to ground in TCC circuit
3. Faulty Transmission Control Module (TCM)
4. Contaminated or low transmission fluid
5. Mechanical failure in the torque converter
6. Valve body issues

Possible Fixes:

1. Check transmission fluid – flush if dirty or burnt
2. Scan live data for TCC lockup status and control signals
3. Inspect wiring and connectors (look for shorts, damage, corrosion)
4. Test or replace TCC solenoid
5. Clean or repair valve body, especially if sticking valves
6. Replace torque converter if internal failure is confirmed
7. In some cases, reprogram or replace TCM

Vehicles Commonly Affected:

1. Chrysler, Dodge, Jeep
2. Honda/Acura (common and serious)
3. GM trucks/SUVs
4. Ford (less common but possible)