Brake System Pressure Sensor Circuit Failure
The brake system pressure sensor is faulty or the circuit has an issue.
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What it means (plain English)
The brake pressure sensor measures how much pressure is in the brake system. If this sensor is broken or the wires are damaged, the computer can't tell how hard you're pressing the brakes.
What the computer is actually seeing
The engine control unit (ECU) doesn't receive a valid signal from the brake pressure sensor, which should send a voltage between 0.5V (low pressure) and 4.5V (high pressure).
What a healthy reading looks like
Normal operation shows a voltage between 0.5V and 4.5V; a reading outside this range indicates a fault or circuit issue.
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 wiring and connectors leading to the brake pressure sensor for visible damage or corrosion. - If damaged, repair or replace the wiring/connectors.
- 22. Check the brake fluid level in the reservoir. - If low, fill it and retest. If not, proceed to next step.
- 33. Measure the voltage at the brake pressure sensor while someone presses the brake pedal. You should see a voltage change between 0.5V and 4.5V. - If voltage is outside this range, replace the brake pressure sensor.
- 44. If the sensor is within expected values, test the vehicle's ECU for faults or glitches. - If faults are found in the ECU, further diagnostics or replacement may be needed.
Common causes
- Faulty brake pressure sensor
- Damaged wiring or connectors
- Corroded connections
- Faulty ECU
Typical repair cost
$$ ($200 - $600)
Related codes
Frequently asked questions
Is it safe to drive with this code?
It’s best to fix this soon. You could experience reduced braking performance.
Will this fault come back after I fix it?
If the wiring and sensor are repaired properly, it shouldn't return.
Why does this code also show up with SPN 1770?
SPN 1770 relates to low brake pressure which could indicate the same sensor issues.
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