C0066high severityChassis
ABS Pressure Circuit Malfunction
on 2018 Mazda Mazda3 2.5L I4 · FWD
What this code means
General fault in the ABS hydraulic pressure sensing or regulation circuit.
Symptoms
- ABS light on
- Stability control disabled
- Brake pedal feel abnormal
- ABS may activate unexpectedly
Common causes
- Faulty ABS pressure sensor
- Hydraulic unit internal leak
- Pressure transducer failure
- Wiring to pressure sensor damaged
Diagnostic steps
- Read ABS pressure sensor values with scan tool
- Compare commanded versus actual pressure
- Inspect pressure sensor wiring
- Check for brake fluid leaks at ABS unit
- Test pressure transducer
Repair notes
Replace ABS pressure sensor or hydraulic unit as needed.
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