C0087moderate severityChassis
Master Cylinder Pressure Sensor Circuit High
on 2021 Mazda Mazda3 2.5L I4 · FWD
What this code means
High voltage from the master cylinder brake pressure sensor circuit.
Symptoms
- ABS light on
- Brake system warning
- Stability control fault
- False high-pressure reading
Common causes
- Signal wire open or shorted to voltage
- Faulty pressure sensor
- Connector corrosion
- Reference voltage issue
Diagnostic steps
- Test sensor signal voltage with brake released and applied
- Check for open circuits in signal wire
- Inspect connector for corrosion
- Verify reference voltage at sensor
Repair notes
Repair wiring or replace brake pressure sensor.
Other Chassis codes on this vehicle
C0021
LF Wheel Speed Sensor Range/Performance
C0022
RF Wheel Speed Sensor Range/Performance
C0023
LR Wheel Speed Sensor Range/Performance
C0024
RR Wheel Speed Sensor Range/Performance
C0025
LF Wheel Speed Sensor Circuit Intermittent
C0026
RF Wheel Speed Sensor Circuit Intermittent
C0027
LR Wheel Speed Sensor Circuit Intermittent
C0028
RR Wheel Speed Sensor Circuit Intermittent
C0035
Left Front Wheel Speed Sensor Circuit
C0036
Left Front Wheel Speed Signal Erratic