P0571 Code: Cruise Control / Brake Switch A Circuit Malfunction

Reviewed by

Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on June 12th, 2024

Reading Time: 3 minutes
Summary
  • The diagnostic trouble code (DTC) P0571 indicates “Cruise Control/Brake Switch A Circuit Malfunction.”
  • The powertrain control module (PCM) will log this code when it detects an issue with the operation of the brake light switch or, sometimes, the cruise control/brake switch “A” circuit.
  • Common causes of the P0571 code are a defective cruise control/brake switch, wiring problems, and PCM issues.
  • The symptoms of a P0571 code include an illuminated check engine light, unusable  cruise control, the brake lights not turning on, or erratic cruise control operation.

Code P0571 is one of many trouble codes that can be logged and retrieved from the OBD system. Here is some helpful information that can help you understand what getting this code might mean for your vehicle.

What Does the P0571 Code Mean?

If the PCM detects an issue with the operation of the brake light switch, code P0571 is logged.

Diagnostic trouble code (DTC) P0571  stands for “Brake Switch A Circuit.” It is logged when the powertrain control module (PCM) detects an issue with the brake switch or its circuit.

The brake switch is crucial to the operation of your vehicle’s cruise control system, not to mention the stop lamps, shift interlock system for taking the vehicle out of park, etc.

If the PCM detects an issue with the operation of the brake light switch, then code P0571 might be logged. This code might also be logged if the PCM detects a malfunction within the cruise control/brake switch “A” circuit.

The “A” in this code can refer to a specific wire, connector, or harness. Be sure to check out the appropriate manufacturer-specific service manual to determine what the code specifically refers to.

Depending on the severity of the problem, related error codes might also be stored with this DTC. Code P0571 is very similar to error codes P0572 and P0573.

Note: The definition of code P0571 might be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P0571 Code?

An issue with the PCM is a common cause of the P0571 code.

What are the Common Symptoms of the P0571 Code?

How to Diagnose the P0571 Code

If you have significant DIY automotive troubleshooting experience, you can monitor the brake light switch input using a scan tool while operating the brake as an initial test. This method works for codes similar to P0751, as well.

If you have significant DIY automotive troubleshooting experience, you can monitor the brake light switch input using a scan tool while operating the brake as an initial test.

Richard McCuistian, ASE Certified Master Automobile Technician

Keep in mind, however, that different makes and models can set the error code P0571. This does not mean that there is a one-size-fits-all approach to diagnosing its underlying cause. The steps for troubleshooting this code will vary depending on your specific vehicle.

Check out the video below to get an idea of what the diagnostic process for this code might involve:

How to Fix the P0571 Code

Code P0571 shares similar triggers and symptoms with other engine codes. However, the appropriate diagnostic and repair procedure will depend on the specifications of your vehicle. If you’re unfamiliar with auto repair, it’s best to leave the job to a mechanic.

If you’re considering troubleshooting this code on your own, it’s a good idea to refresh your automotive knowledge before attempting any fixes. Consult a vehicle-specific repair manual or an online repair database to learn the appropriate diagnostic procedures for this code.

Where to Get a New Brake Light Switch to Resolve the P0571 Code

If your vehicle has set a P0571 code because of a defective brake light switch, don’t delay replacing the bad part. It can keep you from using the brake light, increasing the risk of accidents, among other problems. Fortunately, with just a few clicks, you can find what you need at CarParts.com.

Visit our website or use our mobile app to check out our high-quality brake light switches, all of which are on hand and ready to ship from a warehouse near you. Use our vehicle selector to check for fitment and toggle our search filters to shop according to your preferred brand or price range.

Expect to find only the best prices when you shop from us. All our brake light switches come with a low-price and lifetime replacement guarantee, helping you get the best value for your money.

Shop now to clear this trouble code in no time!

About The Authors
Reviewed By Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Written By CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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CarParts.com Research Team and Richard McCuistian, ASE Certified Master Automobile Technician