Unable to determine brake lamp switch status
The system is having trouble reading the brake lamp switch status.
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 lamp switch is responsible for signaling when you press the brake pedal. When the system can't read this switch, it may be because of a problem with the switch or its connections.
What the computer is actually seeing
The computer looks for a closed circuit signal when the brake pedal is depressed, indicating the brake lights should be illuminated. This signal typically operates at 12 volts in most systems and can toggle between 0 volts (switch off) and 12 volts (switch on).
What a healthy reading looks like
Expect 0 volts (off) when the brake pedal is not pressed and 12 volts (on) when it is 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 lamp switch and wiring for visible damage or disconnection.
- 22. Test the brake lamp switch: Disconnect the switch and use a multimeter to check for continuity. You should see continuity (0 ohms) when the switch is pressed and none (infinite ohms) when released; replace if faulty.
- 33. Inspect the wiring harness and connections for corrosion or damage. Repair or replace as needed.
- 44. Check for any blown fuses related to the brake lamp circuit.
- 55. If all components test good, scan for additional codes, as the BCM might be at fault if it can't read the switch state reliably.
Common causes
- Faulty brake lamp switch
- Wiring damage or corrosion
- Bad connector to the brake lamp switch
- Faulty body control module (BCM)
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
While it may be drivable, it's best to fix this soon as it affects brake light functionality.
Will this code come back after clearing it?
If the underlying issue isn't resolved, the code will likely return after clearing.
Why might this code appear alongside others?
It often pairs with codes indicating faults in other related systems, like the body control module or brake light failures.
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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