P0743
System
Powertrain (Transmission)
Scanner required
Full-system scanner (engine, ABS, SRS, transmission, service resets)

Torque Converter Clutch Circuit Electrical

Understand P0743, common causes, and the right TOPDON scanner to diagnose it.

Electrical fault in TCC solenoid circuit.

Common symptoms

  • Trans fault light
  • No lockup at highway speed

Typical causes

  • Failed TCC solenoid
  • Wiring in trans connector
  • TCM driver fault

What scanner do you need?

Full-system scanner (engine, ABS, SRS, transmission, service resets)

Use live data and freeze frame to confirm the fault before replacing parts. ABS, SRS, and network U-codes usually require a full-system scanner.

Diagnostic tips

  • Record freeze frame data when the code first sets
  • Clear the code only after fixing the root cause
  • Check for related pending codes that point to a common issue
  • Verify battery voltage is above 12.4V before chasing sensor codes

Recommended TOPDON scanners

Frequently asked questions

Can I diagnose P0743 with a basic code reader?
P0743 may set in the engine module, but related diagnostics often benefit from an enhanced or full-system scanner with live data and freeze frame.
Is it safe to drive with P0743?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.