P0740 Torque converter clutch circuit/open
What P0740 means
The transmission control unit has found an open or faulty circuit for the torque converter clutch solenoid. The converter cannot lock up, so the engine runs at higher revs at cruising speed and the gearbox runs hotter.
P0740 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.
At a glance
- Severity
- Medium
- Typical repair cost
- 150–1200 €
- Workshop time
- 2–10 h
- Repair difficulty
- Hard
- DIY possible
- No
- Check engine light
- Yes
- Affects emissions test
- No
Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.
Symptoms
- Higher engine revs at steady speed
- Increased fuel consumption
- Transmission running hot
- Check engine light on
Common causes
- Failed torque converter clutch solenoid
- Damaged internal gearbox wiring harness
- Corroded or loose gearbox connector
- Transmission control unit fault
Can I keep driving with P0740?
You can keep driving, but have it checked within one to two weeks. Avoid towing, since the gearbox will run hotter.
What to check first
- Inspect the gearbox connector for fluid or corrosion
- Measure the TCC solenoid resistance through the connector
- Check the internal harness
- Replace the TCC solenoid or harness
Related codes
- P0741 Torque converter clutch circuit performance/stuck off
- P0743 Torque converter clutch circuit electrical
- P0735 Gear 5 incorrect ratio
- P0734 Gear 4 incorrect ratio
- P0733 Gear 3 incorrect ratio
- P0732 Gear 2 incorrect ratio
- P0731 Gear 1 incorrect ratio
- P0730 Incorrect gear ratio
Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
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