What it means
The control module checks whether brake pressure sensor E’s reading is plausible. It sets this code when the reading is outside the expected range or does not respond as expected.
At a glance
- Usually lights the ABS or stability-control warning light
- The engine or gearbox may go into limp mode
How it works
Brake pressure sensor E measures hydraulic pressure for the brake control module, which checks that the reading is plausible and responds as expected. C05A2 sets when sensor E's reading drifts, falls outside its expected range, or changes abnormally, including when a loose mounting dampens the signal.
Common causes
Most likely first.
- Sensor reading drifted
- Sensor element aged beyond calibration window
- Sensor mounting loose - signal damping
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
How to diagnose it
- Read ABS codes and freeze-frame data, then compare live sensor E pressure data with brake-pedal application and release.
- Inspect sensor E's mounting and connector for looseness, damage, or corrosion that could distort or interrupt its readings.
- Check the sensor E harness while viewing live data to see whether movement causes erratic readings.
- Compare sensor E's response with other available brake pressure data using the manufacturer's diagnostic information to identify an implausible reading.
- If mounting, wiring, and connector checks pass, test sensor E and verify its calibration using the manufacturer's procedure.
Common fixes
- Secure sensor E if its mounting is loose.
- Repair damaged wiring or connector terminals affecting sensor E's signal.
- Perform the specified calibration if the sensor's calibration is incorrect.
- Replace sensor E if its reading remains implausible after circuit and mounting checks.
Can I keep driving?
ABS and stability control may be unavailable, and brake assist may be reduced while the pressure reading is unreliable. Drive cautiously only if normal braking is intact, leave extra stopping distance, and avoid slippery roads.
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.