Power Supply Fault to Brake Switch Circuit
There’s a power issue 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 isn't getting the power it needs to operate correctly, which can affect brake lights and safety systems.
What the computer is actually seeing
The Powertrain Control Module (PCM) detects a voltage drop or an open circuit in the brake switch supply circuit, typically below 9 volts.
What a healthy reading looks like
Expected voltage at the brake switch power feed is around 12-14 volts with the ignition on. If the switch is activated, it should pull the signal line low (0 volts).
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. Inspect the fuse for the brake switch circuit. Check for continuity and replace if blown. If okay, proceed to step 2.
- 22. Check the brake switch wiring for signs of damage, corrosion, or loose connections. Repair as necessary. If wiring is good, proceed to step 3.
- 33. Measure the voltage at the brake switch connector with the ignition on. You should see 12-14 volts. If voltage is present, replace the brake switch. If no voltage, proceed to step 4.
- 44. Trace wiring back to the power source for shorts or opens, ensuring continuity. If found, repair the wiring. If no issues found, consider inspection of the PCM or related components.
Common causes
- Blown fuse in the brake circuit
- Damaged wiring or connectors
- Faulty brake switch
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best to fix this code soon. The brake lights may not function correctly, which is a safety hazard.
Will this code come back after clearing?
If the underlying issue isn't fixed, such as a damaged wire or faulty switch, yes, it will likely come back.
Why does this code usually pair with others?
It may occur with other codes related to the braking system or power supply due to common wiring issues.
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