P0571: Brake switch A circuit fault, the switch that tells the computer and cruise control when the brake pedal is pressed
Brake switch A circuit (cruise control)
Severity: Inspect soon
KBB says safety is compromised if the brake light circuit is affected, and an owner reports brake lights that would not come on; treat it as brake-related.
It gets more serious if:
- Stop: Stop driving and have it inspected right away if the brake lights do not come on when you press the pedal, or stay on all the time, because following drivers will not see you braking.
P0571 in short
P0571 means the computer sees a fault in the brake switch A circuit, which also tells cruise control when you brake. The usual cause is a failed brake or cruise switch, often after a spill, or damaged wiring. Check that your brake lights work, because safety is affected if they do not.
The brake switch at the pedal tells the computer when you press the brake, so cruise control cancels and the brake lights come on. P0571 sets when the switch signal is missing or does not make sense.
KBB lists a failed switch, often after liquids spill, damaged connector pins, corroded or pinched wires and bad fuses. Cruise control that does not work, a brake pedal that does not cancel cruise and brake light faults are the typical symptoms.
Saturn lists P0571 with an inoperative cruise control on the 2004 Vue. A 2007 Hyundai Santa Fe owner reports a faulty brake switch A/B with brake lights that would not light, and a 2002 Jetta owner describes a brake light switch that stayed on and set P0571.
Most likely causes
Cause 1: Failed brake or cruise cancel switch
Common general cause- Why it ranks here
- KBB lists a failed brake or cruise control switch as the most frequent cause, often after liquid spills; two owners report a faulty switch with P0571.
- What would change this
- Rises if the brake lights act wrong or the switch tests bad at the pedal. Falls if the switch works and adjusts properly.
Cause 2: Damaged connector, wiring or a blown fuse
Common general cause- Why it ranks here
- KBB lists damaged connector pins, corroded or pinched wires and bad fuses.
- What would change this
- Rises if the connector is corroded or a fuse is open. Falls if wiring and fuses test good.
Cause 3: Powertrain control module circuit on the 2004 Vue (Saturn)
Supported by vehicle data- Why it ranks here
- Saturn bulletin 04086804 covers an inoperative cruise control and the SES light with P0571 stored in the powertrain control module; the summary gives no repair.
- What would change this
- Rises on a 2004 Vue with cruise not working. Falls on other vehicles.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Have someone watch the brake lights while you press the pedal, and note whether cruise control works.
IfBrake lights do not light or stay on
It meansStop driving until the switch is fixed.
IfBrake lights work and cruise control does not
It meansInspect the switch and connector.
Step 2: Inspect the brake switch at the pedal, its connector and wiring for spill damage and corrosion, and check the related fuse.
IfThe switch is damaged or contaminated
It meansReplace the switch.
IfA connector, wire or fuse is faulty
It meansRepair it.
IfOn a 2004 Saturn Vue with cruise inoperative
It meansAsk a dealer about the bulletin.
Points to: Powertrain control module circuit on the 2004 Vue (Saturn)
Symptoms
- Cruise control does not work
- Brake lights do not light with the pedal pressed Gets more serious: stop and have it checked.
- Brake lights stay on Gets more serious: stop and have it checked.
- Check engine light on
How to fix
This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.
On your vehicle
SaturnYour car
2004 · Vue
Supported by vehicle dataSaturn bulletin 04086804 covers cruise control that does not work with P0571 stored. Whether the bulletin is still current is not verified.
04086804Status unverified
Cruise control inoperative with P0571
2004vue · NHTSA 10010510
Cruise control inoperative and/or the SES light on with P0571 stored in the powertrain control module.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
HyundaiYour car
2007 · Santa Fe
Supported by vehicle dataA 2007 Santa Fe owner reports a faulty brake switch A/B with P0571 and P0504 and brake lights that did not light.
VolkswagenYour car
2002 · Jetta
Possible — needs testingA 2002 Jetta owner reports a brake light switch that stays on and sets P0571, covered by a recall for a limited VIN range.
Related codes
P0571 questions
Why is my cruise control dead with P0571?
The computer will not allow cruise control without a valid brake switch signal. A failed switch is the usual cause.
Does it affect my brake lights?
It can. Have someone check that the lights come on with the pedal, and stop driving if they do not.
Sources and review
- P0571 code page (OBD-II codes)
- NHTSA complaint ODI 10475283: Hyundai Santa Fe 2007, faulty brake switch A/B with P0571
- NHTSA complaint ODI 10322862: Volkswagen Jetta 2002, brake light switch stays on and P0571 set
- Saturn bulletin 04086804 (NHTSA 10010510): 2004 Vue cruise control inoperative with P0571
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error