Brake Switch A Circuit Range/Performance Problem
The brake pedal switch circuit isn't performing as expected.
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)
Inside the vehicle's computer, there's a switch that detects when you press the brake pedal. When it's not working right, the computer thinks you're never pressing the brake, which can mess with other systems, like cruise control.
What the computer is actually seeing
The brake switch is supposed to send a signal of 0.5-2.5 volts when the pedal is pressed. If it stays below 0.5 volts or above 2.5 volts consistently without switch movement, it triggers this code.
What a healthy reading looks like
Expected voltage at the brake switch should be between 0.5-2.5 volts when the brake pedal is pressed and close to 0 volts when released.
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.
- 1Check the brake switch connector for corrosion and proper seating.
- 2Inspect wiring for any signs of damage or shorts. Repair as needed. Decision Point: Is the wiring intact? Yes: go to step 3. No: repair wiring and retest.
- 3Using a multimeter, measure the voltage at the brake switch while pressing the pedal. Decision Point: Is the voltage between 0.5-2.5 volts? Yes: go to step 4. No: replace the brake switch and retest.
- 4Check if the vehicle's brake lights are operational. Decision Point: Are the brake lights working? Yes: clear the code and monitor. No: troubleshoot the brake light circuit.
Common causes
- Faulty brake switch
- Poor electrical connection at the brake switch
- Damaged wiring in the brake switch circuit
- Faulty brake light bulbs
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It's not a safety risk, but it can affect functions like cruise control.
Will this code come back after clearing it?
If the problem isn't repaired, yes, it will likely return.
Why does this code pair with P0573?
P0573 indicates high voltage; it's often seen together if the brake switch is malfunctioning.
Working a real vehicle right now?
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