Brake Switch A Circuit Fault
Indicates an issue with the brake switch circuit.
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 light switch sends a signal to the computer when you press the brake pedal. If that signal is weak or missing, the computer registers a fault.
What the computer is actually seeing
The brake switch should show a closed circuit (near 0 volts) when the brake pedal is pressed and an open circuit (around the battery voltage, typically 12-14 volts) when released.
What a healthy reading looks like
Brake switch voltage should be close to 0 volts when pressed and near 12-14 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. Check the brake fluid level. Ensure it's within the recommended range and not causing pedal issues.
- 22. Inspect the wiring and connectors at the brake switch for damage, corrosion, or loose connections.
- 33. Use a multimeter to test the brake switch: measure voltage with the pedal pressed (should be 0 volts) and released (should be 12-14 volts).
- 44. If no voltage change is observed, replace the brake switch. If voltage is good, check the wiring back to the BCM.
- 55. After repairs, clear the code and test drive to see if the code returns.
Common causes
- Faulty brake switch
- Wiring issues
- Corroded or loose connectors
- Faulty body control module (BCM)
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate; you may have reduced brake lights which could be risky for other drivers.
Will I need to replace the entire switch?
Not necessarily; sometimes just cleaning connections or fixing wiring can resolve the issue.
Why does this code come with other codes?
Multiple codes may indicate several faults related to the brake system or BCM issues.
Working a real vehicle right now?
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