What it means
The brake control module reports that brake pressure sensor A has not been calibrated. The affected brake or stability functions may be limited until calibration is completed.
How it works
Brake pressure sensor A reports hydraulic pressure to the brake control module for functions such as stability control. This code means the module has not recorded the required calibration for sensor A, so functions that rely on its pressure reading may be limited.
Common causes
Most likely first.
- Required calibration not performed after service
- Calibration drive cycle incomplete
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
How to diagnose it
- Scan the brake module for calibration status and related codes to confirm that sensor A calibration is the unresolved issue.
- Review recent brake or sensor service to determine whether calibration was required but not completed.
- Check live brake pressure sensor A data at rest and during a controlled pedal application for plausible response.
- Inspect sensor A’s connector and wiring if its data is missing or implausible, since calibration cannot correct an electrical fault.
- Perform the manufacturer-specified calibration and any required drive cycle, then verify calibration status.
Common fixes
- Complete the required brake pressure sensor A calibration with the specified scan-tool procedure.
- Complete the manufacturer-required calibration drive cycle.
- Repair a loose or damaged sensor A connector or wiring if its reading is implausible.
- Recheck calibration status and clear the code after successful setup.
Can I keep driving?
Base braking may remain available, but ABS or stability functions can be limited until sensor A is calibrated. Drive cautiously and avoid relying on stability assistance until calibration is complete.
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.