Code
C0121
Brakes / ABS
ABS valve / solenoid relay malfunction
The ABS hydraulic unit valve circuit has a fault.
Advertisement
Most likely causes
- Faulty ABS solenoid
- Relay fault
- Wiring fault
Symptoms you may notice
- ABS light
- ABS disabled
Checks to run
- Test ABS relay
- Check solenoid circuits
- Inspect wiring
Tools you may need
Multimeter
Always diagnose before replacing. Codes share symptoms; confirm the cause with measurements before buying parts.