P0571 Code Meaning and Next Steps

First checks take 10 to 15 minutes for the first checks. No special tools are usually needed for the first checks.

Can you keep driving?

Stop driving if any of these apply

!The engine starts running much worse, stalls, or the warning light flashes.
!The vehicle loses power sharply or the electrical system is acting unstable while the code is active.

If the light is steady and the vehicle still drives normally: Often yes for a short time, but it should not be ignored.

What to check first

Step-by-step checks

1
Free - no tools
Check whether the brake lights work normally and whether they stay on or fail to come on as expected
2
Free - no tools
Inspect the brake switch mount, connector, and pedal position for looseness or misadjustment
3
Basic tool needed
See whether cruise control drops out normally when the brake pedal is pressed
4
Basic tool needed
If the code appeared after pedal-area work, confirm the switch adjustment first
5
Basic tool needed
If scan data is available, watch the brake signal while pressing and releasing the pedal

If the code returns

-If the brake signal is unstable, the switch or adjustment is a stronger suspect than the ECU.
-If the code returns after connector repair, revisit the pedal position and harness continuity.
-If other brake-related symptoms are present, the switch circuit should stay high on the list.

Background

What this code means

P0571 is a generic OBD-II brake-switch circuit code.

The ECU is not seeing the brake switch signal correctly, which can affect cruise control, shift interlock, and brake-light behavior.

A brake-light problem, cruise fault, or shifting oddity can show up with this code.

Diagnosis

Common causes

Most common

Brake switch misadjustment

The switch may be mounted too far in or out to signal correctly.

Common

Brake switch failure

The switch can wear out or stick internally.

Common

Connector or wiring issue

A loose or damaged connection can interrupt the signal.

Possible

Pedal stop or mount issue

A physical adjustment problem can make the switch behave incorrectly.

Avoid these mistakes

What not to do

xDo not replace parts before checking the battery, connectors, fuses, and switch inputs that feed the circuit.
xDo not ignore drivability changes just because the code sounds like a switch or voltage issue.

Parts

Parts that may need replacing

PartTypical costNotes

Brake light switch$15-$80Most relevant when the signal test fails or the switch sticks.

Connector repair$15-$90Worth checking if the plug or pins are damaged.

Pedal stop or mounting hardware$5-$40Useful when the switch is out of adjustment.

Related OBD codes

P0572

P0572 usually means brake switch A circuit is reading too low.

P0573

P0573 usually means brake switch A circuit is reading too high.

P0565

P0565 usually means cruise control on signal malfunction.

Source notes

Generic OBD-II (SAE J1979 / ISO 15031-5). P0571 was expanded around common brake-switch circuit faults, including switch adjustment, connector issues, and wiring problems.

This guide is written as a generic multi-make reference, so bulletin history, sensor locations, and repair order can still change by manufacturer and engine family.

This is generic OBD-II guidance and should not override vehicle-specific service information. Exact diagnosis and repair steps vary by make, engine family, and model year.

Last reviewed: 2026-04-10

Reference: Open reference

P0571 - P0571 Usually Means Brake Switch a Circuit Malfunction