Torque Converter Clutch Circuit Malfunction
2012-2012 Subaru Legacy 3.6L H6
The 2012 Subaru Legacy is equipped with a 3.6L flat-6 engine. Below you'll find detailed p0740 diagnostic code information including labor time estimates, cost ranges, and technician notes specific to this engine configuration.
Description
Malfunction in the torque converter clutch (TCC) solenoid circuit.
Symptoms
- Check Engine Light
- No lockup feel (higher RPM at highway)
- Poor fuel economy
- Transmission overheating
Common Causes
- Faulty TCC solenoid
- Wiring issue
- PCM driver failure
- Torque converter failure
Diagnostic Steps
- Test TCC solenoid resistance
- Check wiring
- Command TCC engagement with scan tool
- Monitor RPM drop during lockup command
Repair Notes
Replace TCC solenoid or repair wiring. Solenoid is often inside transmission.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P0740 on Other Vehicles
Common Questions
What does code P0740 mean on a 2012-2012 Subaru Legacy?
P0740 stands for "Torque Converter Clutch Circuit Malfunction". Malfunction in the torque converter clutch (TCC) solenoid circuit.
What are the symptoms of P0740 on a Subaru Legacy?
Common symptoms of P0740 include: Check Engine Light, No lockup feel (higher RPM at highway), Poor fuel economy, Transmission overheating.
What causes P0740 on a 2012-2012 Subaru Legacy?
Common causes of P0740 include: Faulty TCC solenoid, Wiring issue, PCM driver failure, Torque converter failure.
Last updated: March 2026