Brake Switch A Circuit
The brake switch is reporting an incorrect condition.
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 pedal has a switch that tells the computer when you press it. If this switch isn’t working right, the computer thinks the brake is always pressed or never pressed, which messes up the vehicle's functions like cruise control or the transmission.
What the computer is actually seeing
The computer expects to see a voltage change at the brake switch: 0 volts when not pressed and 5 volts when pressed. If it sees a constant voltage that doesn’t match this, it triggers this code.
What a healthy reading looks like
Brake switch should show 0V (off) when the pedal is not pressed and around 5V (on) when 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.
- 1Check the brake pedal operation and ensure it moves freely.
- 2Inspect the brake switch for visible damage or wear.
- 3Test for voltage at the brake switch connector: 0V when pedal is unpressed, 5V when pressed. If values are off, replace the switch.
- 4Check wiring and connectors for damage, corrosion, or disconnection.
- 5If the switch and wiring check out but the code persists, consider scanning for other related codes to pinpoint further issues.
Common causes
- Faulty brake switch
- Wiring issues in the brake switch circuit
- Connector problems
- Corrosion or moisture in connectors
- Faulty ABS module
Typical repair cost
$$ - $$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally drivable, but be cautious of cruise control and transmission shifting issues.
Will this code come back after clearing?
If the underlying issue isn’t fixed, the code will return after clearing.
Why does this sometimes affect my cruise control?
The brake switch input is crucial for cruise control; if the system thinks brakes are engaged, it won't allow cruise control to function.
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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