P0743: Torque Converter Clutch Solenoid Circuit Electrical

What does P0743 mean?

An electrical fault is detected in the torque-converter clutch solenoid circuit. The computer may lose the ability to apply or release lockup correctly, but the code does not alone prove the converter is mechanically damaged.

Generic OBD-II definition: Torque Converter Clutch Solenoid Circuit Electrical. Confirm applicability in your vehicle service information.

Common causes

• TCC winding or internal harness fault
• Short to power/ground or open external wiring
• Poor connector or supply problem

Symptoms

• Shudder when starting or stopping
• Possible stalling
• Check engine light

Diagnostic focus

Check the actual electrical fault rather than prescribing a fluid flush. Fluid condition matters, but it will not repair an open winding or chafed control wire.

Can I keep driving with P0743?

Severity: Medium Avoid towing, steep loads, and prolonged driving until diagnosed. Stop and arrange recovery if the transmission slips, loses drive, overheats, or bangs into gear; driving through slip can cause further damage.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

• Inspect TCC wiring and the case connector
• Test the solenoid winding and feed/control paths
• Verify operation before considering converter replacement

Sources & review

• OBD-Codes.com: P0743
• TroubleCodes.net: generic code definitions

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.