Faulty brake switch (OBD-Codes.com, RepairPal). Wiring problem, such as a wire pinched at the brake pedal, chafed, or shorted to voltage (all three sources). Faulty engine computer (PCM/ECM), less common (all three sources). Brake switch out of adjustment (OBD-Codes.com). Brake switch knocked out of its mount (OBD-Codes.com). Dirt or debris stopping the switch from moving (OBD-Codes.com). Faulty body control module on vehicles where it supplies the brake signal, such as the GM Trax (GM service information).

Replace the brake switch, following the manufacturer's install and adjustment procedure (OBD-Codes.com, RepairPal). Re-mount or adjust a switch that has come loose or is misadjusted (OBD-Codes.com). Repair a wire shorted to voltage, or chafed or corroded wiring, in the brake switch signal circuit (all three sources). Repair or replace the engine computer, or the body control module where it supplies the signal, only after the switch and wiring test good (all three sources).

P0573🔧 Brake pedal switch / cruise controlStop and fix promptly

P0573: Brake Switch A Circuit High (Meaning, Causes, Fixes)

Q: What does P0573 mean?

P0573 means the engine computer saw a voltage that's too high on the brake switch 'A' circuit, the switch that tells it you're pressing the brake pedal and usually also turns on the brake lights. The most common results are cruise control that won't work and brake lights that don't behave normally. Common causes are a faulty or misadjusted brake switch, a wire shorted to voltage near the pedal and, less often, the engine computer. The brake switch sits on the brake pedal arm under the dash. It tells the engine computer when the pedal is pressed so cruise control can switch off, and on most cars it also powers the brake lights. OBD-Codes.com says P0573 sets when the computer detects a high electrical condition in the cruise control/brake switch 'A' circuit, and that the 'A' may refer to a specific wire, connector or harness only your service manual can identify. GM's service information for the Chevrolet Trax gives a more specific example: there, P0573 sets when the engine computer sees voltage on the brake signal wire while a data message from the body control module says the brakes are not applied, which points to a wire shorted to voltage. RepairPal describes the trigger differently, saying the code sets when the computer sees the vehicle slowing down without the brake switch reporting that the pedal is pressed; that is the same wording RepairPal uses for P0571, so it doesn't explain the 'high' part. The sources also word the code slightly differently: OBD-Codes.com calls it 'Cruise Control/Brake Switch A Circuit High', RepairPal uses 'Brake Switch "A" Circuit High', and GM calls it 'Brake Switch Circuit 1 High Voltage'. OBD-Codes.com lists P0571 and P0572 as related codes and notes that on some cars the body control module (BCM), not the engine computer, runs cruise control. It is a generic code that can appear on any OBD-II vehicle.

Q: Can I keep driving with P0573?

Stop and fix promptly. Check your brake lights before driving. The same brake pedal switch usually turns on your brake lights, and both main sources list brake lights not working as a possible symptom, which means drivers behind you may not see you slowing down. RepairPal rates P0573 Urgent. OBD-Codes.com calls it moderately severe, explaining that cruise control faults are usually low priority but a possible brake switch problem is a real safety concern. If your brake lights don't come on, or stay on all the time, get it fixed before driving, and don't rely on cruise control.

Reviewed 2026-10-23 · Based on 3 cited source(s)

What P0573 means

The brake switch sits on the brake pedal arm under the dash. It tells the engine computer when the pedal is pressed so cruise control can switch off, and on most cars it also powers the brake lights. OBD-Codes.com says P0573 sets when the computer detects a high electrical condition in the cruise control/brake switch 'A' circuit, and that the 'A' may refer to a specific wire, connector or harness only your service manual can identify. GM's service information for the Chevrolet Trax gives a more specific example: there, P0573 sets when the engine computer sees voltage on the brake signal wire while a data message from the body control module says the brakes are not applied, which points to a wire shorted to voltage. RepairPal describes the trigger differently, saying the code sets when the computer sees the vehicle slowing down without the brake switch reporting that the pedal is pressed; that is the same wording RepairPal uses for P0571, so it doesn't explain the 'high' part. The sources also word the code slightly differently: OBD-Codes.com calls it 'Cruise Control/Brake Switch A Circuit High', RepairPal uses 'Brake Switch "A" Circuit High', and GM calls it 'Brake Switch Circuit 1 High Voltage'. OBD-Codes.com lists P0571 and P0572 as related codes and notes that on some cars the body control module (BCM), not the engine computer, runs cruise control. It is a generic code that can appear on any OBD-II vehicle.

Severity: can I keep driving?

Stop and fix promptly

Check your brake lights before driving. The same brake pedal switch usually turns on your brake lights, and both main sources list brake lights not working as a possible symptom, which means drivers behind you may not see you slowing down. RepairPal rates P0573 Urgent. OBD-Codes.com calls it moderately severe, explaining that cruise control faults are usually low priority but a possible brake switch problem is a real safety concern. If your brake lights don't come on, or stay on all the time, get it fixed before driving, and don't rely on cruise control.

Common symptoms

Cruise control not working at all (all three sources)
Brake lights not coming on if the switch is faulty (OBD-Codes.com, RepairPal)
Erratic cruise control, or cruise that turns on but won't engage (OBD-Codes.com)
Cruise buttons like set, resume or accelerate not working properly (OBD-Codes.com)
On the GM Trax, the check engine light does not come on for this code; the only action listed is that cruise control is disabled (GM service information)

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

Faulty brake switch (OBD-Codes.com, RepairPal)
Wiring problem, such as a wire pinched at the brake pedal, chafed, or shorted to voltage (all three sources)
Faulty engine computer (PCM/ECM), less common (all three sources)
Brake switch out of adjustment (OBD-Codes.com)
Brake switch knocked out of its mount (OBD-Codes.com)
Dirt or debris stopping the switch from moving (OBD-Codes.com)
Faulty body control module on vehicles where it supplies the brake signal, such as the GM Trax (GM service information)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

Have someone watch the rear of the car while you press and release the brake pedal. Brake lights that don't come on, or that stay on with the pedal released, point to the switch or its wiring, and that's a safety issue to fix right away.
Look under the dash at the switch on the brake pedal arm. OBD-Codes.com says a driver's foot sometimes knocks the switch out of its mount or breaks it off, which you can see right away.
Check that the switch is adjusted correctly and that nothing is stopping it from moving freely (OBD-Codes.com).
Inspect the wiring and connector at the switch for pinched, chafed or corroded wires, and clean corroded pins with electrical contact cleaner. OBD-Codes.com suggests a continuity test of the circuit with a multimeter, using your service manual's wiring diagram and specs.
Check for technical service bulletins (TSBs) for your vehicle, which OBD-Codes.com recommends as the first step.

Typical fixes

Replace the brake switch, following the manufacturer's install and adjustment procedure (OBD-Codes.com, RepairPal)
Re-mount or adjust a switch that has come loose or is misadjusted (OBD-Codes.com)
Repair a wire shorted to voltage, or chafed or corroded wiring, in the brake switch signal circuit (all three sources)
Repair or replace the engine computer, or the body control module where it supplies the signal, only after the switch and wiring test good (all three sources)

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

Your brake lights don't work, or stay on, and you can't fix the switch yourself
The switch needs a specific adjustment procedure you don't have
Wiring tests point to a short to voltage you can't find, or to the engine or body control module
The code comes back after a new, properly adjusted switch

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Can I drive with P0573?

First check that your brake lights work normally. If they don't, get it fixed before driving, since drivers behind you won't see you braking. RepairPal rates P0573 Urgent and OBD-Codes.com calls it moderately severe.

What's the difference between P0571 and P0573?

P0571 is a general fault in the brake switch 'A' circuit, while P0573 specifically means the circuit voltage is too high. GM's Trax service information, for example, sets P0573 for a short to voltage on the brake signal wire.

Why is my check engine light off but the code is stored?

Some vehicles don't turn on the check engine light for this code. GM's service information for the Trax says the light will not come on for P0573; it only disables cruise control.

How much does it cost to fix P0573?

None of the sources gives a repair cost for P0573. It can range from adjusting the switch to replacing it or repairing wiring, so diagnose it first.

Sources

Last reviewed 2026-10-23. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.