What it means
The module compares brake pressure sensor M’s signal with the expected range and pressure behavior. It sets this code when the signal is out of 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 M measures hydraulic pressure for the brake control module’s ABS and stability decisions. This code sets when the module finds sensor M’s reading outside its expected range or sees it respond inconsistently as brake pressure changes.
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
- Save freeze-frame data and monitor live sensor M pressure while applying the brake gently to see whether the reading is plausible and follows pressure changes.
- Inspect sensor M’s mounting and connector for looseness, damage, contamination, or signs of movement that could damp the signal.
- Check related brake pressure sensor readings and scan for other brake-system codes that could help distinguish a sensor M fault from a shared system issue.
- Inspect sensor M’s wiring and verify its supply, ground, and signal circuit against the manufacturer's specification.
- If the circuit is sound, test sensor M against actual brake pressure and check its mounting or calibration as directed by the manufacturer.
Common fixes
- Secure a loose sensor M mounting or connector.
- Repair damaged sensor M wiring or connector terminals.
- Replace sensor M if its reading drifts or fails to track pressure with a verified circuit.
- Perform any required manufacturer-specified calibration after repair.
Can I keep driving?
Use caution because ABS and stability control may be disabled, and brake assist may be reduced. Avoid slippery roads and hard braking until the pressure reading is reliable.
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.