Brake Switch Circuit Failure
There’s a fault in 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 tells the vehicle's computer when you're pressing the brake. If there’s a problem, the computer can’t know when the brake is applied, which can affect safety features like cruise control or automatic transmission shifting.
What the computer is actually seeing
The brake switch sends a signal to the engine control module (ECM) when the brake is engaged. It typically provides a voltage signal between 0-5 volts. If the signal is inconsistent or absent, the ECM triggers this code.
What a healthy reading looks like
When brake is depressed, expect a voltage between 0.2V and 5.0V; with brake released, it should be close to 0V.
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. Begin with a visual inspection of the brake switch and wiring for any obvious damage or disconnected connectors. Check for corrosion.
- 22. Using a multimeter, check the voltage at the brake switch with the brake pedal depressed. Expect 0.2V to 5.0V. If the voltage is out of spec, replace the brake switch.
- 33. If the brake switch voltage is good, check the wiring harness continuity to the ECM. Look for opens or shorts. Repair if necessary.
- 44. With the wiring intact and the switch functioning, check the ECM for faults. If all else fails, a reprogram or replacement of the ECM may be needed.
Common causes
- Faulty brake switch
- Wiring issues in the brake switch circuit
- Connector corrosion or damage
- ECM malfunction
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It's not recommended since you may lose brake-related functions like cruise control or safety features.
Will this code come back after I clear it?
If the underlying issue isn’t fixed, yes, it will return.
Why does this code pair with SPN 58?
SPN 58 relates to the brake switch circuit too, indicating a common issue in the system.
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