P0740

Torque Converter Clutch Circuit/Open

Q: Is it safe to drive with P0740?

For short trips, yes. The converter clutch just isn't locking up, so avoid sustained highway driving until it's fixed to keep the transmission from overheating.

Q: Can I just clear P0740?

You can, but it returns until the solenoid or circuit fault is repaired — the TCM checks the TCC circuit continuously.

Transmission / torque converter Generic OBD-II Medium

What it means

P0740 means the transmission control module found an open or fault in the torque converter clutch (TCC) circuit, so the converter clutch can't lock up. Without lockup the engine turns faster at cruising speed, fuel economy dips, and the transmission runs hotter. It's usually electrical — a bad solenoid or wiring — rather than a broken transmission.

Medium

Can I keep driving? Drivable, but with no converter lockup the engine runs at higher rpm and the transmission runs hotter — avoid long highway trips until it's fixed.

Real-world scan data

Seen in

165

scans in the past year

Found in

<0.1%

of scans

0.1%

of scans that found faults

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Higher-than-normal engine rpm at steady cruising speed (no lockup)
Slightly reduced fuel economy
Transmission running hotter than usual

Common causes

Most likely first

Faulty torque converter clutch (TCC) solenoidLikely
Open or damaged wiring / connector in the TCC circuitCommon
Loose or corroded electrical connectionsCommon
Low or dirty transmission fluid affecting solenoid operationLess often
Failed transmission control module (TCM)Less often

How to diagnose & fix

Work through it in order

Read freeze-frame data and confirm the code; check for other transmission codes.
Inspect the TCC solenoid connector and wiring for opens or corrosion.
Check transmission fluid level and condition.
Measure the TCC solenoid resistance and replace it if open or out of spec.
If the solenoid and wiring are good, evaluate the TCM. Clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0740?+

For short trips, yes. The converter clutch just isn't locking up, so avoid sustained highway driving until it's fixed to keep the transmission from overheating.

Can I just clear P0740?+