Brake Switch Circuit Low Input
The brake switch input signal is lower than expected, indicating a malfunction.
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What it means (plain English)
The brake switch tells the computer when you're pressing the brake pedal, but it's sending too low of a signal, which can lead to issues with braking systems and cruise control.
What the computer is actually seeing
The computer expects a voltage signal around 0.5 volts when the brake pedal is released and about 4.5 volts when the brake pedal is pressed. Low readings indicate a fault in the brake switch circuit.
What a healthy reading looks like
0.5 volts (released) to 4.5 volts (pressed) on brake switch input signals.
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 fluid level - ensure it's at the correct level. Decision: Is the level correct?
- 22. Inspect the brake switch connector and wiring - look for corrosion or damage. Decision: Are the connectors in good condition?
- 33. Using a multimeter, measure the voltage at the brake switch. With the pedal not pressed, it should read 0.5 volts; with the pedal pressed, it should read around 4.5 volts. Decision: Are the values within range?
- 44. If the voltage readings are low at the brake switch, replace the brake switch. Decision: Did replacing it fix the code?
- 55. If the previous steps pass, check the vehicle’s ground connections related to the brake system. Decision: Are ground connections solid?
Common causes
- Faulty brake switch
- Wiring issues (frayed or shorted harness)
- Failed brake pedal position sensor
- Poor ground connections
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It’s moderate severity; it can affect your braking performance, so it’s best to repair it soon.
Will this issue come back after fixing?
If the repair includes replacing the brake switch and verifying wiring, it should not return.
Why is this code showing up with cruise control issues?
The system relies on the brake signal to disengage cruise control; a low input can cause erratic behavior.
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