The ABS system is a mandatory safety feature found on all late model vehicles. It serves to help slow down the vehicle and prevent wheel lock and tire skid during heavy braking situations. As is the case with the systems on most modern vehicles, the ABS system is electronic in nature, and uses an electronic relay to supply it with power. It is the job of the ABS relay to supply power to the ABS module, pump, and the rest of its components so that they can successfully serve their purpose.
Because the ABS relay is what supplies power to the entire system, when it malfunctions or has a problem, that problem can quickly transfer to the rest of the system, so it should be serviced as soon as possible. Usually, when the ABS relay fails, the vehicle will produce a few symptoms that can alert the driver that there may be a potential problem.
Check Engine Light / ABS Light is on
One of the first symptoms of a defective ABS relay is an illuminated Check Engine or ABS Light. If the computer detects that the relay has failed, or is giving an abnormal reading, then it will activate the Check Engine or ABS Light to alert the driver of a potential problem. The Check Engine and ABS Lights can come on for a variety of reasons, so having the computer scanned for trouble codes can help shed some light on what the exact problem may be.
Unexpected wheel lock from ABS system failing
Another symptom of a problem with the ABS sensor is a non-functioning ABS system. If the ABS sensor fails or malfunctions, then the entire ABS system will be without power and will be unable to function, sometimes without activating the ABS or Check Engine Light. The vehicle may still brake normally, however, the assisted braking provided by the ABS system will be disabled, which may leave the vehicle more susceptible to wheel lock and tire skidding during heavy braking and slippery conditions.
The ABS system is an important safety feature found on virtually all modern vehicles, and as is the case with most automotive systems, it is fed power through a relay. For this reason, if you suspect that your ABS system may be malfunctioning, or needs to have the anti-lock relay replaced, a professional technician, such as one from YourMechanic, can diagnose the vehicle and verify what repairs are required.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Anti-Lock Relay and was authored by Valerie Johnston.