Active Brake Booster
The brake control module has detected a fault in the active (electric or vacuum-controlled) brake booster. Active boosters are used by emergency brake assist and adaptive cruise control to autonomously build brake pressure.
Affected components
- Active brake booster
- Brake control module
- Vacuum pump
Common causes
- High likelihood: Active booster motor or solenoid failed
- Medium likelihood: Vacuum supply weak (vacuum pump or hose fault)
- Low likelihood: Wiring or connector fault
Possible symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.