U0127high severityNetwork
Lost Communication with Parking Brake Control Module
on 2021 Mazda Mazda3 2.5L I4 · FWD
What this code means
Cannot communicate with the electronic parking brake module.
Symptoms
- Parking brake warning light
- Electronic parking brake inoperative
- Brake warning message
- Cannot release parking brake
- Hill hold not working
Common causes
- EPB module failure
- CAN bus wiring
- Module power loss
- Fuse blown
- EPB actuator failure
Diagnostic steps
- Check EPB module fuse
- Test module power and ground
- Check CAN wiring
- Try manual EPB release procedure
- Test EPB actuator motors
Repair notes
If parking brake is stuck engaged, use manual release procedure first. Check fuses.
Other Network codes on this vehicle
U0001
High Speed CAN Communication Bus
U0002
High Speed CAN Communication Bus Performance
U0003
High Speed CAN Communication Bus (+) Open
U0004
High Speed CAN Communication Bus (+) Low
U0005
High Speed CAN Communication Bus (+) High
U0006
High Speed CAN Communication Bus (-) Open
U0007
High Speed CAN Communication Bus (-) Low
U0008
High Speed CAN Communication Bus (-) High
U0009
High Speed CAN Communication Bus Shorted Together
U0010
Medium Speed CAN Communication Bus