C0440critical severityChassis
Automatic Emergency Braking System Fault
on 2023 Mazda Mazda3 2.0L I4 · AWD
What this code means
General malfunction in the automatic emergency braking system.
Symptoms
- AEB warning light
- Automatic braking disabled
- Forward collision mitigation unavailable
- Driver assist systems degraded
Common causes
- Radar module fault
- Camera system error
- Brake system unable to support AEB
- Module communication failure
Diagnostic steps
- Check for radar and camera codes
- Verify ABS/brake system is fully functional
- Test communication between AEB controller and brake module
- Inspect all AEB-related sensors
- Check for software updates
Repair notes
Diagnose root sensor or brake system fault. AEB relies on both detection and braking subsystems.
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