What it means
A fault is detected in the brake booster pressure sensor power-supply circuit. The sensor may not provide a reliable pressure reading.
At a glance
- Usually lights the ABS or stability-control warning light
- The engine or gearbox may go into limp mode
How it works
The brake booster pressure sensor measures pressure used by the brake-assist system, and its power-supply circuit provides the sensor with the electricity needed to report that reading. This code indicates a fault in that supply path, so the module may not receive a reliable pressure measurement.
Common causes
Most likely first.
- Open or short in sensor power supply wiring
- Loose or corroded connector
- Faulty pressure sensor
- Control module fault
Symptoms
- Brake or ABS warning light
- Brake assist may be reduced, depending on the system
How to diagnose it
- Read brake-module freeze-frame and live pressure data to see whether the sensor reading is missing, fixed, or implausible when the fault occurs.
- Inspect the pressure sensor connector for looseness, corrosion, damaged seals, or pushed-back terminals.
- Trace the sensor power-supply wiring for opens, shorts, or chafing near the booster and harness bends.
- Using the wiring diagram, check sensor supply and ground at the connector and test continuity to the controlling module.
- If supply wiring and connections meet the manufacturer's specification, test the pressure sensor and module circuit before replacing parts.
Common fixes
- Reconnect and secure the pressure sensor plug.
- Clean or repair corroded sensor connector terminals.
- Repair an open or shorted section of the sensor supply wiring.
- Replace the pressure sensor or repair the module only if circuit tests identify it as faulty.
Can I keep driving?
Brake assist may be reduced if the system cannot trust booster pressure, so allow extra stopping distance and avoid unnecessary driving. If pedal effort or braking response changes, stop safely and have the brake system checked.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.