P0744Powertrain
Powertrain · SAE
Torque Converter Clutch Solenoid Intermittent
Meaning
The transmission control module has detected that the TCC solenoid is operating intermittently: the control signal or solenoid response drops outside expected parameters sporadically rather than consistently.
Common causes
- Loose or intermittently oxidised TCC solenoid connector
- Wiring harness with micro-fractures or damaged insulation causing intermittent contact under heat
- TCC solenoid coil that short-circuits or opens at specific temperatures
- Valve body with TCC valve that occasionally sticks due to deposits
- Low ATF level or degraded fluid causing intermittent pressure variations
Symptoms
- Check engine light (often intermittent)
- Slight vibration or occasional shudder during highway cruising
- Slightly increased fuel consumption, not constant
- Torque converter sometimes engages and sometimes does not under cruise conditions
- Symptoms may disappear after the vehicle cools down
Severity
Moderate: the intermittent fault causes no immediate damage but signals a deteriorating condition that can progress to a permanent failure.
What to do
- Check ATF level and condition; replace if degraded
- Carefully inspect the TCC solenoid connector and wiring for corrosion, micro-fractures, or looseness
- Monitor TCC live data with a scan tool during driving to reproduce and localise the fault
- Test TCC solenoid resistance both cold and at operating temperature
- Replace the TCC solenoid or valve body if the problem persists after wiring inspection