Brake Switch Circuit Failure
There's a problem 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 switch, which tells the computer when you're pressing the brakes, isn't sending the right signals. This can prevent the car from shifting or affect other systems that depend on brake status.
What the computer is actually seeing
The engine control module (ECM)/body control module (BCM) expects a voltage change (typically 0.5V when off and around 12V when activated) from the brake switch. If it doesn’t see this change as expected, it logs an error.
What a healthy reading looks like
Brake switch should show 12V when engaged and about 0.5V when disengaged (with a good ground and battery connection).
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 brake fluid level; low fluid can affect the brake switch operation.
- 2Inspect the brake switch physically for damage or misalignment.
- 3Test the brake switch circuit with a multimeter; voltage should be 0.5V when unpressed and around 12V when pressed. If not, replace the brake switch.
- 4Check wiring and connectors for corrosion or breaks; repair if necessary and retest the brake switch operation.
- 5Scan for other fault codes; sometimes, related codes can yield additional insight on wiring or component failures.
Common causes
- Faulty brake switch
- Wiring issues in the circuit
- Poor connector contact
- Faulty BCM/ECM
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's drivable but may affect braking features; address it soon to avoid potential hazards.
Will this code come back after I clear it?
If the underlying issue isn't fixed, it likely will return after a short time.
Why does this code sometimes pair with other codes?
Brake switch status affects multiple systems; related codes often indicate further issues in those systems.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →