How to Fix P0571 Cruise Control/Brake Switch A Circuit Malfunction

The P0571 diagnostic trouble code indicates a malfunction in the cruise control/brake switch A circuit. This code is triggered when the vehicle’s powertrain control module (PCM) detects an issue with the electrical circuit associated with the brake switch. Fixing this problem is crucial for maintaining proper cruise control function and ensuring the safety of your vehicle. In this comprehensive guide, we’ll walk you through the steps to diagnose and repair the P0571 code.

Understanding the P0571 Code

The P0571 code is a generic code that applies to all vehicles equipped with electronic cruise control systems. When the PCM detects a problem with the brake switch A circuit, it sets the P0571 code and illuminates the check engine light. This malfunction can cause the cruise control system to fail to disengage when the brake pedal is pressed, which poses a significant safety risk.

Symptoms of a P0571 Code

When the P0571 code is triggered, you may experience the following symptoms:

Cruise control not functioning properly
Illuminated check engine light
Issues with shifting gears (in some vehicles)
Decreased brake performance (in some cases)

Diagnosing the P0571 Code

To diagnose the P0571 code, follow these steps:

Visual Inspection: Begin by inspecting the brake switch, usually located near the brake pedal, for any signs of damage or wear.
Check the Wiring: Examine the wiring and connectors leading to and from the brake switch for signs of corrosion, damage, or loose connections.
Use a Multimeter: With a multimeter, check for continuity in the brake switch circuit. A lack of continuity indicates a broken circuit, which could be the source of the problem.
Scan for Codes: Use an OBD-II scanner to check for any additional codes that may indicate related issues or provide more insight into the malfunction.

Fixing the P0571 Code

To fix the P0571 code, you may need to repair or replace the following components:

Brake Switch: If the brake switch is faulty, it will need to be replaced. Locate the switch near the top of the brake pedal, disconnect the battery, remove the old switch, and install the new one.
Wiring and Connectors: If the problem lies within the wiring or connectors, repair or replace any damaged wires and secure any loose connections.

After making the necessary repairs, clear the P0571 code using an OBD-II scanner and take the vehicle for a test drive to ensure the problem has been resolved.

If you’re uncomfortable performing these repairs yourself, it’s always best to seek the assistance of a professional mechanic. They have the expertise and tools necessary to diagnose and fix the P0571 code correctly.