U0121
Lost Communication with ABS Module
2016-2021 Mazda CX-3 2.0L I4 🇨🇦
High SeverityNetwork
Description
Cannot communicate with the Anti-lock Brake System module.
Symptoms
- ABS light on
- Traction control disabled
- Stability control disabled
Common Causes
- ABS module power failure
- CAN bus wiring
- ABS module failure
- Fuse blown
Diagnostic Steps
- Check ABS fuses
- Test module power and ground
- Check CAN wiring
- Try direct communication
Repair Notes
Check fuses first. Common on water-damaged vehicles.
Related Codes
Other Network Codes
- U0001High Speed CAN Communication Bus
- U0001High Speed CAN Communication Bus
- U0002High Speed CAN Communication Bus Performance
- U0002High Speed CAN Communication Bus Performance
- U0003High Speed CAN Communication Bus (+) Open
- U0003High Speed CAN Communication Bus (+) Open
- U0004High Speed CAN Communication Bus (+) Low
- U0004High Speed CAN Communication Bus (+) Low
- U0005High Speed CAN Communication Bus (+) High
- U0005High Speed CAN Communication Bus (+) High
U0121 on Other Vehicles
Common Questions
What does code U0121 mean on a 2016-2021 Mazda CX-3?
U0121 stands for "Lost Communication with ABS Module". Cannot communicate with the Anti-lock Brake System module.
What are the symptoms of U0121 on a Mazda CX-3?
Common symptoms of U0121 include: ABS light on, Traction control disabled, Stability control disabled.
What causes U0121 on a 2016-2021 Mazda CX-3?
Common causes of U0121 include: ABS module power failure, CAN bus wiring, ABS module failure, Fuse blown.