P0571
System
Powertrain (Cruise Control)
Scanner required
Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

Cruise Control/Brake Switch A Circuit Malfunction

Understand P0571, common causes, and the right TOPDON scanner to diagnose it.

Brake switch circuit fault — cruise control may not cancel or set properly.

Common symptoms

  • Cruise won't set or cancel
  • Brake lights inop on some models

Typical causes

  • Failed brake light switch
  • Adjustable brake pedal switch misadjusted
  • Wiring at brake pedal

What scanner do you need?

Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

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 P0571 with a basic code reader?
P0571 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 P0571?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.