Brake Booster Pressure Sensor Circuit High
The brake booster pressure sensor is sending a voltage signal that is higher than the expected range to the PCM. This indicates a problem with the sensor circuit, vacuum system, or the sensor itself that affects brake system performance monitoring.
What You Might Notice
- Check Engine Light illuminated
- Check Brake Light flashing or staying on
- Increased brake pedal effort required
- Soft or spongy brake pedal feel
- Brake system warning messages displayed
Most Common Causes
- 1
Defective brake booster pressure sensor
The sensor may be internally shorted or failing, causing it to output an excessive voltage signal to the PCM.
- 2
Corroded or damaged connector
Corrosion, loose connections, or damaged pins in the sensor connector can cause high voltage readings in the circuit.
- 3
Damaged or faulty wiring
Broken, pinched, or shorted wiring between the sensor and PCM can result in abnormal voltage levels being detected.
- 4
Vacuum line issues or defective brake booster
Worn or damaged vacuum lines, or a failing brake booster, can affect sensor readings and cause the circuit high condition.
How to Diagnose It
- 1
Check Defective brake booster pressure sensor — The sensor may be internally shorted or failing, causing it to output an excessive voltage signal to the PCM.
- 2
Check Corroded or damaged connector — Corrosion, loose connections, or damaged pins in the sensor connector can cause high voltage readings in the circuit.
- 3
Check Damaged or faulty wiring — Broken, pinched, or shorted wiring between the sensor and PCM can result in abnormal voltage levels being detected.
- 4
Check Vacuum line issues or defective brake booster — Worn or damaged vacuum lines, or a failing brake booster, can affect sensor readings and cause the circuit high condition.
How to Fix It
- 1
Inspect and test brake booster pressure sensor
Use a multimeter to measure the sensor voltage output with the engine running and key in different positions. Compare readings to manufacturer specifications. Replace the sensor if voltage is consistently high.
- 2
Check and clean sensor connector
Disconnect the sensor connector and inspect for corrosion, moisture, or loose pins. Clean contacts with electrical contact cleaner and dielectric grease. Reconnect firmly and retest.
- 3
Inspect wiring harness and repair
Visually trace the wiring from the sensor to the PCM for signs of damage, pinching, or exposed conductors. Repair or replace damaged sections of harness as needed.
- 4
Inspect vacuum system and brake booster
Check vacuum lines for cracks, splits, or disconnection. Verify brake booster operation by checking for proper braking response and vacuum hold. Replace damaged lines or booster if necessary.
Need a deeper diagnosis?
Search for related repair guides or browse by system.