C0056high severityChassis
ABS Front Outlet Valve Solenoid Circuit
on 2004 GMC Yukon 5.3L V8 Vortec · RWD
What this code means
Malfunction in the front ABS outlet valve solenoid, which releases brake pressure during ABS activation.
Symptoms
- ABS light on
- Front brakes lock during ABS event
- Brake pedal hard during ABS activation
- Poor ABS performance
Common causes
- Outlet valve solenoid stuck
- ABS modulator internal failure
- Electrical fault in solenoid driver
- Contaminated brake fluid causing valve sticking
Diagnostic steps
- Test solenoid resistance at module connector
- Command valve with scan tool
- Check brake fluid condition
- Inspect module connector
- Check for related pump motor codes
Repair notes
Replace ABS hydraulic modulator if solenoid is faulty. Flush brake fluid.
Other Chassis codes on this vehicle
C0021
LF Wheel Speed Sensor Range/Performance
C0022
RF Wheel Speed Sensor Range/Performance
C0023
LR Wheel Speed Sensor Range/Performance
C0024
RR Wheel Speed Sensor Range/Performance
C0025
LF Wheel Speed Sensor Circuit Intermittent
C0026
RF Wheel Speed Sensor Circuit Intermittent
C0027
LR Wheel Speed Sensor Circuit Intermittent
C0028
RR Wheel Speed Sensor Circuit Intermittent
C0035
Left Front Wheel Speed Sensor Circuit
C0036
Left Front Wheel Speed Signal Erratic