P0740 — Torque Converter Clutch Circuit
Moderate severityWhat it means
P0740 is stored when the engine control unit sees a fault involving the torque converter clutch (TCC) circuit. The torque converter clutch locks the converter at cruising speed to save fuel; a circuit fault can cause shudder, stalling or poor economy. The control unit has flagged this circuit or signal as outside its normal operating range.
Common symptoms
- Shudder or vibration at cruising speed
- Stalling when coming to a stop
- Poor fuel economy or RPM that won't settle
Likely causes
- A wiring, connector or ground problem in the circuit
- A failed sensor or actuator in the circuit
- Faulty TCC solenoid
- Low/dirty fluid or a valve-body problem
What to check first
- Inspect the connector and wiring for damage, corrosion or loose pins
- Check TCC lock-up in live data at steady cruise
- Inspect fluid condition and the solenoid connector
Can you keep driving?
Often drivable, but stalling at stops is a safety concern and fluid issues can worsen — diagnose soon.
Frequently asked questions
What is the most common cause of P0740?
The most likely cause is: A wiring, connector or ground problem in the circuit. Several other faults can set P0740 as well, so confirm the real cause with live data and the checks above before replacing any parts.
Can I just clear P0740 and keep driving?
Clearing P0740 with an OBD2 scanner turns the warning light off, but if the underlying fault has not been repaired the code will usually come back within a few drive cycles. Fix the cause first, then clear the code to confirm the repair worked.
How serious is P0740?
P0740 is a moderate-severity code. The car is often still drivable, but have it diagnosed soon — the underlying problem can get worse and it may fail an emissions test.
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