P0742
System
Powertrain (Transmission)
Scanner required
Full-system scanner (engine, ABS, SRS, transmission, service resets)

Torque Converter Clutch Circuit Stuck On

Understand P0742, common causes, and the right TOPDON scanner to diagnose it.

TCC stuck engaged — engine may stall at stops or shudder.

Common symptoms

  • Stalling when stopping
  • Shudder at low speed
  • Rough idle in gear

Typical causes

  • Stuck TCC solenoid
  • Valve body fault
  • Internal converter clutch welded

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 P0742 with a basic code reader?
P0742 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 P0742?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.