P1790
Lock-Up Clutch Not Engaging
Severity
⚠️ MediumCan you drive?
Yes, but get it checked soon
Approx. repair cost
$33–167 (est.)
Symptoms
- Increased fuel consumption
- Reduced acceleration dynamics
- Transmission fluid overheating
- Vibration when driving at constant speed
- Rough idling
Causes
- Torque converter malfunction
- Lockout Solenoid Problems
- Contaminated or low transmission fluid level
- Malfunction of the blocking valve in the valve body
- Problems with wiring or transmission ECU
How to Fix
- Check the level and condition of the transmission fluid
- Diagnose the operation of the locking solenoid
- Check the pressure in the transmission control system
- Perform hydraulic unit diagnostics
- If necessary, replace the torque converter