Brake Switch A Circuit High
The brake switch signal is higher than expected.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The car's computer thinks the brake pedal is pressed when it's not due to a high voltage signal from the brake switch.
What the computer is actually seeing
The brake switch sends a signal voltage around 0.5-2.5 volts when pressed; anything above 2.5 volts triggers this code.
What a healthy reading looks like
Correct brake switch signal should be between 0.5-2.5 volts when the pedal is pressed and less than 0.2 volts when released.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the brake switch wiring and connectors for damage or corrosion. If damaged, repair or replace as needed. Decision Point: Is the wiring intact? If yes, proceed to step 2. If no, fix the wiring.
- 22. Using a multimeter, check the voltage at the brake switch. With the brake pedal depressed, it should read between 0.5-2.5 volts. If it reads above 2.5 volts or is stuck high, replace the brake switch. Decision Point: Is the voltage normal? If yes, proceed to step 3. If no, replace the switch.
- 33. Check the vehicle's wiring harness for shorts to power sources that may cause a high signal. Use the multimeter to measure continuity. Decision Point: Is there continuity where it shouldn't be? If yes, repair the harness; if no, further diagnose the computer.
Common causes
- Faulty brake switch
- Wiring issue or short in the brake switch circuit
- Faulty brake pedal position sensor
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderate severity means you can drive, but fix it soon to prevent brake system issues.
Will this code come back after clearing it?
If the underlying issue isn't fixed (like a bad switch or wiring), it will likely return.
Why do I see related codes like P0571 or P0572?
Those codes indicate similar issues with the brake switch circuit, either too low or possibly intermittent signal.
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