Lost Communication with ABS Module
Communication with the anti-lock brake system module has been lost.
Informational only. Consult a qualified mechanic.
- Faulty ABS module
- CAN bus wiring
- Connector issue
ABS and stability control are disabled. Have module and wiring checked.
What does U0121 mean?
The U0121 OBD-II diagnostic trouble code (DTC) indicates: lost communication with abs module. This is a high-severity network code that your vehicle's onboard diagnostics system triggers when communication with the anti-lock brake system module has been lost. If your check engine light is on with this code, the vehicle is generally safe to drive, but you should have it inspected soon.
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