What is an ABS system?
This system was designed with occupant safety in mind. The anti-lock braking (ABS) system is used to maintain wheel motion and traction while braking, accelerating or cornering on a slippery surface. This system uses the same components as the traction control system (TCS), and the functionalities of both are integrated through the ABS control module.
How does the ABS system work?
The ABS system is designed to keep the brakes from stopping one or more wheels while the vehicle is in motion by quickly engaging and disengaging the brakes in rapid succession until the vehicle is out of harm's way. The ABS control module is the brain of this system, and is physically attached to the brake lines, via the distribution block, to control the amount of pressure that is being applied when the driver depresses the brake pedal. Because traction control is integrated into the ABS system, the ABS module may pulse the brakes or reduce engine power during cornering to prevent wheel spin, even if the brakes are not applied.
A malfunctioning ABS system can cause the ABS, traction control, brake, and possibly the Check Engine lights to illuminate. Speedometer operation may stop as well.
What are the symptoms of an ABS system problem?
A failure in the ABS or TCS will leave the brakes functioning normally, but without the added security of traction control and anti-lock brakes. When the ABS control module detects a fault, the ABS light, traction control light, and any manufacturer specific stability control lights will illuminate on the instrument cluster, alerting you to have the systems inspected for faults.
Can I drive with an ABS system problem?
The vehicle can be driven with these warning lights on, since failure of the ABS or TCS does not disable the vehicle, but
safety is a concern as drivers become accustomed to the road manners of their vehicles. If hard braking that is normally controlled by the ABS control module is necessary,
a collision may occur. We do recommend towing the vehicle to a repair facility if the brakes feel unusual under light or normal driving conditions.
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How often does the ABS system require diagnosis?
ABS system components can fail at any mileage, and under any conditions. However the wheel speed sensors, which monitor the speed of wheel rotation, are prone to failure as they are housed near the road surface, and subject to dust, debris, precipitation, salt, and road hazards.
How is the ABS system diagnosed?
Anti-lock braking systems are complex, and are typically diagnosed through professional computer scanning equipment, or manufacturer specific software. The technician will communicate with the ABS control module via computer, and view real-time data to determine what fault has been detected, and how the system is behaving. Once the technician identifies a suspected failure in the system, physical inspection and probing will take place to ensure an accurate diagnosis.
ABS control module failures can set diagnostic codes for wheel speed sensors, ABS pump motors, and other ABS system parts. Replacing those items will not address the problem and repair or replacement of the ABS control module will still be required.
As part of an ABS system diagnosis, the wheel speed sensors should be checked for looseness and dirt. Sometimes securing a loose sensor and/or cleaning the wheel speed sensors will address the ABS issue.
Just like your computer at home, the ABS system may need occasional software upgrades to address various issues. A quality shop will check with the vehicle manufacturer for any Technical Service Bulletins (TSBs) related to the problems you're having and will upgrade the software when possible.