Brake Switch Circuit Failure
Issue with the brake light switch circuit detected.
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 signals when you press the brake pedal, but the system isn't getting that signal properly, so it thinks there's a problem with the switch or wiring.
What the computer is actually seeing
The brake control module is not receiving a signal from the brake switch indicating that the brake pedal is being pressed.
What a healthy reading looks like
A closed circuit (0V) when the brake pedal is pressed and an open circuit (around 12V) 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. Check the brake pedal position. Ensure it moves freely and fully engages the switch.
- 22. Inspect brake light operation: Press the brake pedal and see if the brake lights illuminate. If not, replace the brake light bulb or switch.
- 33. Test the brake switch with a multimeter: Measure voltage at the switch connector while pressing the brake pedal. You should see 0V when pressed and battery voltage (around 12V) when released. If not, replace the switch.
- 44. Check for wiring damage: Inspect the wiring from the switch to the brake control module for any signs of fraying, corrosion, or breaks.
- 55. Verify ground connections: Ensure the brake light switch has a good ground. Test continuity to ground.
- 66. If the switch and wiring are good, check the brake control module for faults.
Common causes
- Faulty brake light switch
- Wiring issues or shorts in the brake light circuit
- Corrosion at connectors or grounds
- Faulty brake control module
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Yes, but you may have an issue with stopping properly since brake lights may not work, affecting safety.
Will this code come back after clearing?
It may come back if the underlying issue is not fixed, like a faulty switch or bad wiring.
Why does this code show up with other codes?
It often pairs with other brake-related codes due to interconnected circuits that share the brake light switch signal.
Working a real vehicle right now?
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