What is ABS? Reasons for ABS Light Activation, Repair Costs, and Whether You Can Still Drive

ABS stands for Anti-Lock Brake System. It was first proposed in the early 20th century to reduce the risk of railway carriages breaking at connecting points. In 1920, French engineer Gabriel Voisin applied a flywheel-based brake control system to aircraft, which was later adapted for railways and aviation. In the early 1970s, Mario Palazzetti at the Italian Fiat Research Center improved it with electronic control, naming it Antiskid, laying the foundation for modern ABS. Bosch later acquired this patent and named it Anti-Lock Brake System.

Mercedes-Benz was the first car manufacturer to use electronically controlled hydraulic ABS in 1978 on the S-Class, and today, ABS is a standard safety feature in all vehicles.

When braking, if excessive force is applied, the wheels may lock up, causing the vehicle to slide while still in motion, potentially leading to brake system failure or loss of control. ABS intervenes automatically by rapidly releasing and reapplying the brakes to maintain control and shorten braking distances.

ABS is a simple design but operates on a complex principle. It relies on sensors in the braking system, an electronic control unit (ECU) in the vehicle, and an ABS pump to detect wheel rotation. It involves extensive and precise calculations, requiring high reliability of sensors and the computer’s signal processing ability.

1. Sensors: ABS sensors can be covered with dust or dirt, or they might shift position, affecting signal transmission and causing the ABS light to come on
2. Wiring: ABS wiring is similar to standard electrical wiring but is often covered with plastic. Exposure to sunlight, rain, and dust can cause it to age and crack. Wiring connectors can also become loose and need careful inspection.

3. Electronic Control Unit: The ABS ECU is a circuit board responsible for processing data. Errors in programming or water damage can trigger the ABS light. Reprogramming might solve the issue, but water damage may require a complete ECU replacement.

4. ABS Pump: The ABS pump is crucial for providing braking power. Problems with the pump can disable the entire ABS system. Generally, ABS pumps are durable and rarely fail unless exposed to severe water damage or collisions.

If there’s an issue with the ABS sensors or wiring, a simple cleaning or adjustment might solve the problem. If not, replacement of sensors or wiring typically costs around HKD 1,000 to 2,000, including parts and labor.

If the problem involves the ECU or ABS pump, repairs can be more costly. Replacing the ABS pump, which may include the ECU, can exceed HKD 10,000.