HSA

📖 YOUCANIC Automotive Glossary

HSA (Hill Start Assist), also called HHC (Hill Hold Control) or HAC (Hill-start Assist Control), automatically holds brake pressure for 1-3 seconds after the driver releases the brake pedal on an incline, preventing the vehicle from rolling backward during the transition from brake to accelerator. The system detects the vehicle is on a slope using the longitudinal accelerometer or inclinometer and maintains brake pressure through the ABS hydraulic modulator until the driver applies throttle and the drivetrain engages. HSA is standard on most modern vehicles with automatic and manual transmissions.

HSA operates within the ABS/ESC module using existing hardware. Faults are rare but can include incorrect slope detection, premature release, or failure to activate. HSA-related issues are diagnosed through ABS/ESC module codes. The YOUCANIC UCAN-II reads the relevant module codes affecting HSA operation.