C0121high severityChassis
Electronic Parking Brake Motor Overcurrent
on 2019 Mazda Mazda3 2.0L I4 · AWD
What this code means
The EPB motor is drawing more current than the module can supply.
Symptoms
- EPB warning light
- Parking brake partially applied
- Grinding noise when EPB activates
- EPB applies slowly
Common causes
- EPB motor seized or binding
- Brake caliper seized
- EPB cable or mechanism corroded
- Motor brushes worn
Diagnostic steps
- Command EPB apply and release, monitor current draw
- Inspect rear brake calipers for binding
- Check EPB mechanism for corrosion
- Test motor current draw with ammeter
- Lubricate EPB mechanism if accessible
Repair notes
Replace EPB motor or caliper if mechanism is seized. Clean and lubricate if corrosion is the cause.
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