P0740
System
Powertrain (Transmission)
Scanner required
Full-system scanner (engine, ABS, SRS, transmission, service resets)

Torque Converter Clutch Circuit Malfunction

Understand P0740, common causes, and the right TOPDON scanner to diagnose it.

TCC solenoid electrical fault — related to P0741 performance code.

Common symptoms

  • Shudder
  • Poor highway economy
  • Check engine light

Typical causes

  • Failed TCC solenoid
  • Wiring in trans harness
  • TCM 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 P0740 with a basic code reader?
P0740 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 P0740?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.