AutoCodes – Lexus – P0571 Lexus

P0571 Lexus Code - Brake Switch 'A' Circuit

Quick Answer

When the brake pedal is depressed, the stop light switch assembly sends a signal to the Engine Control Module (ECM). Common causes include Faulty Brake Switch, Misadjusted brake switch, Brake Switch harness is open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0571 Lexus indicates Brake Switch 'A' Circuit.
Common causes: Common causes include Faulty Brake Switch, Misadjusted brake switch, Brake Switch harness is open or shorted.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 9,192

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 02, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0571 Lexus Description

When the brake pedal is depressed, the stop light switch assembly sends a signal to the Engine Control Module (ECM). When the ECM receives this signal, it cancels the cruise control. The fail-safe function operates to enable normal driving even if there is a malfunction in the stop light signal circuit. The cancellation condition occurs when voltage is applied to terminal STP. When the brake is applied, voltage is normally applied to the terminal STP of the ECM through the STOP fuse and the stop light switch assembly, and the ECM turns the cruise control system off. The Diagnostic Trouble Code (DTC) will be set when the ignition switch is turned ON and the dynamic radar cruise control system is operating, voltage of the STP terminal and that of the ST1- terminal of ECM are less than 1 V for approximately 0.5 seconds or more.

OBDII Code P0571 Lexus - Brake Switch 'A' Circuit - AutoCodes.com — P0571 Lexus Code - Brake Switch 'A' Circuit

What does this mean?

What are the Possible Causes of the DTC P0571 Lexus?

Faulty Brake Switch
Misadjusted brake switch
Brake Switch harness is open or shorted
Brake Switch circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0571 Lexus?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0571 Lexus code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.