U0121Lost Communication with ABS Control Module
The vehicle network lost communication with the ABS control module.
This code also has a manufacturer-specific definition:
Can I keep driving? With caution
You can drive to the shop, but do not postpone the repair. The problem may worsen and damage other components.
Sistema Afectado
Red CAN · Comunicación entre módulos
Falla de comunicación en la red CAN: pérdida de datos entre las unidades de control (ECU).
Espacio para vendedores de repuestos
Aún no hay un anunciante en este espacio.
Symptoms You Will Notice
What you may observe when this code appears
- ABS light on
- Possible loss of ABS function
- Stability light on
Possible Causes
The components or conditions that trigger this code
- 1Faulty ABS module
- 2CAN network problem
- 3Blown fuse
- 4Damaged wiring
How to Fix It — Step by Step
Recommended diagnostic and repair procedure
- 1Check the ABS system fuses
- 2Check the module power supply
- 3Inspect the network communication
- 4Test the ABS module with a scan tool
Note: This information is for general reference. For precise diagnostics and safety repairs, always consult a certified mechanic.
Estimated Cost
Approximate range in USD (varies by region and shop)
Communication modules
* Diagnosis only: $50–$150
Quick Info
Dig Deeper
Videos, images and service manuals
Have Another Code?
Look it up directly: