Brake Switch Fault
The brake pedal position switch has a malfunction.
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 brake switch isn't sending the right signal to the computer when you press the brake pedal, making it think you're not braking when you actually are.
What the computer is actually seeing
The engine control unit (ECU) is monitoring the brake switch input voltage. A low voltage (below 0.5V) or high voltage (above 4.5V) indicates a fault because it should be between 0.5V and 4.5V when the brake pedal is pressed or released.
What a healthy reading looks like
Brake switch voltage should be around 0.5V when the pedal is released and close to 4.5V when fully pressed.
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. Check the brake light operation. Do the brake lights illuminate when the pedal is pressed? If not, go to step 2. If they do work, proceed to step 3.
- 22. Inspect the brake switch and wiring for damage or disconnection. Fix if necessary and retest. If still no brake light operation, replace the brake switch.
- 33. Measure voltage at the brake switch connector with the brake pedal pressed and released. Is the voltage between 0.5V and 4.5V? If yes, the switch is functioning. If not, go to step 4.
- 44. Check the wiring from the brake switch to the ECU for continuity and shorts. If wiring is good, consider replacing the ECU.
Common causes
- Faulty brake switch
- Wiring or connector issues
- Corrosion or debris at the switch
- Malfunctioning ECU
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's drivable, but you won't have proper brake signal which can affect other systems like cruise control.
Will this code come back after clearing?
If not resolved, it will likely return after a few drives as the issue remains.
Why did this code appear with a cruise control issue?
The brake switch is integral to cruise control; if it's not functioning, cruise control may disable or malfunction.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
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