What is the Anti-Lock Control Relay all about?

The term “anti-lock control relay” is something of a misnomer. The relay doesn’t operate the controller – the controller operates the relay. The relay itself is responsible for operating the pump, which pressurizes brake fluid in the ABS system’s accumulator. If the relay fails, then the pump will not operate and the fluid pressure in the accumulator will not build. The end result is that the ABS system won’t work. Essentially, the anti-lock control relay is used to energize the electric pump in some types of ABS systems. This will vary from one system to the next, and is dependent not on the automaker so much as on the manufacturer of the ABS system. Like other electrical components, the anti-lock control relay is subject to wear and tear. Over time, it’s possible that it will fail, although pump failure is more common than relay failure, and fuse failure is more common than both. In all instances, failure means that the ABS system will stop functioning and the ABS warning light will illuminate in the dash.

Keep in mind:

• All relays are subject to failure due to normal wear and tear.
• The anti-lock control relay is not inspected during any maintenance service, and will only be checked if there is a problem with the ABS system.
• Many other problems can mimic symptoms of anti-lock control relay failure, including pump failure and blown fuses.

How it's done:

• The anti-lock control relay is verified to see if it needs to be replaced
• The defective anti-lock control relay is removed
• The new anti-lock control relay is installed
• The anti-lock control relay is tested for operation
• The vehicle is tested to ensure proper operation of the anti-lock control relay

Our recommendation:

The anti-lock control relay is responsible for sending electricity to the ABS pump, which pressurizes the accumulator. Without an operational relay, the pump cannot operate and the pressure inside the accumulator cannot be maintained. The brakes will still work, but you will have to exert more effort to apply them. Have any brake system problem diagnosed and repaired immediately by one of our expert mechanics.

What common symptoms indicate you may need to replace the Anti-Lock Control Relay?

• ABS light is on
• ABS pump does not operate
• ABS system does not operate

How important is this service?

Anti-lock brake failure can cause increased stopping distances, and you may not be able to avoid a collision. The anti-lock control relay is responsible for operating the pump at the command of the control unit. Relay failure means that the entire ABS system will be inoperable, although you will still have normal (manual) braking capabilities. Seek immediate professional diagnosis from one of our expert mechanics to determine the actual cause of any ABS problem and have it repaired immediately.