ABS

📖 YOUCANIC Automotive Glossary

ABS (Anti-lock Braking System) prevents wheel lockup during hard braking by rapidly modulating brake pressure at each wheel independently. The ABS module monitors wheel speed sensors on all four wheels — when it detects one wheel decelerating significantly faster than the others (indicating impending lockup), it commands the ABS hydraulic modulator to rapidly pulse brake pressure at that wheel, allowing it to continue rotating and maintaining steering control. The system operates through solenoid valves and a pump motor within the hydraulic modulator.

ABS problems trigger the ABS warning light and DTCs in the C0xxx range. Common causes: wheel speed sensor faults (C0035-C0050), tone ring damage, sensor wiring issues, ABS module failure, and low brake fluid. The YOUCANIC UCAN-II reads ABS-specific codes (invisible to basic code readers), performs ABS bleeding (cycling internal solenoid valves), and runs wheel speed sensor live data to identify which sensor is faulty by comparing all four readings during driving.