Parts
$20-300
P0740 — Torque Converter Clutch Circuit Malfunction
CAUTIONIs it safe to drive? The torque converter lockup clutch circuit has a problem. The trans may hunt gears at highway speeds and economy will drop — address it soon.
What P0740 means
The TCC solenoid is supposed to mechanically lock the torque converter at cruising speed for efficiency. A circuit fault means the PCM can't control this solenoid — you get slippage at cruise (higher RPM, poor mpg) or shudder if it's stuck on.
Most likely causes (in order)
- Faulty TCC solenoid (most common)
- Wiring / connector fault to the solenoid
- Low or burnt transmission fluid (the solenoid runs on fluid pressure)
- Internal TCC clutch wear (see also P0894)
Symptoms you might notice
- RPM too high at cruise
- Poor fuel economy
- TCC shudder
- Limp mode
What to check first
Check fluid level and condition first. Use a scanner to command TCC on and watch RPM — if it doesn't drop at cruise, solenoid or circuit. A shudder ON lockup = internal TCC wear (fluid treatment first, then mechanical).
Repair cost & difficulty
Labor
0.5-4 hr
Difficulty
Moderate