Brake Switch Circuit Closed
The brake switch is indicating it is closed when it should not be.
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 that tells the truck's computer when you’re pressing the brake is stuck closed, which messes with the system that controls your brakes and engine management.
What the computer is actually seeing
The computer is seeing a continuous signal from the brake switch, indicating that the brakes are always applied, even when they're not.
What a healthy reading looks like
The brake switch should show 0 volts (off) when the brake pedal is not pressed and close to battery voltage (around 12-14 volts) 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.
- 11. Check the brake switch wiring and connectors for damage or corrosion. If damaged, repair or replace.
- 22. Measure voltage at the brake switch: ignition on, pedal not pressed. Expect 0 volts. If not, there’s a wiring issue.
- 33. With the brake pedal pressed, check the voltage at the switch again. It should be close to battery voltage (12-14 V). If not, the switch is faulty and needs replacement.
- 44. If both voltages are correct, check the related control unit for faults or errors that could cause sensor misreading.
Common causes
- Faulty brake switch
- Wiring issues or short circuits in the brake switch circuit
- Bad connectors or corrosion in the brake system wiring
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
No, this code indicates a brake function issue that can cause loss of braking ability.
Will this code come back after clearing it?
If the issue isn't fixed, it will likely return after clearing and driving.
Why does this pair with other codes?
It's common for brake-related issues to affect or trigger multiple systems, leading to several codes.
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 →