Brake Switch Circuit Range/Performance Problem
The brake switch is not sending the correct signal to the engine control module (ECM).
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 is supposed to tell the computer when you press the brake pedal. If it doesn't send the right signal, the computer can't tell when you're braking, which can affect things like cruise control and stability control.
What the computer is actually seeing
The ECM expects a closed circuit (low voltage around 0-1V) when the brake pedal is pressed, and an open circuit (high voltage close to battery voltage) when it's released. If it sees inconsistent values or no change, it triggers this code.
What a healthy reading looks like
Brake switch signal should switch from ~0.5V (brake not pressed) to ~0V (brake pressed), and vice versa, almost instantaneously (within a few milliseconds).
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.
- 1Check the brake fluid level; low fluid can affect brake operation.
- 2Inspect the brake switch wiring for any visible damage or corrosion.
- 3Test the brake switch operation with a multimeter; expect 0V when pressed and near battery voltage when released.
- 4If the switch is functional and wiring is intact, use a scan tool to check for additional codes or pending codes that could indicate further issues.
- 5Repair any wiring faults or replace the brake switch if necessary, then clear the code and test drive.
Common causes
- Faulty brake switch
- Wiring issues or shorts in brake switch circuit
- Connector corrosion or damage
- Faulty ECM
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate severity; you can drive, but be cautious of systems that rely on brake input like cruise control.
Will this code come back after clearing it?
Yes, if the underlying issue isn't fixed, the code will return.
Why does this code sometimes pair with cruise control issues?
Because the brake switch is critical for disabling cruise control when the brake is pressed.
Working a real vehicle right now?
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