I'm not going to get into these systems too deep here, but I will try to address some of the common questions I get about ABS/TCS. ABS stands for Antilock Brake System. TCS stands for Traction Control System. I list these together because they involve many of the same parts and are closely related systems.
ABS came about to help maintain steering control during the event of a panic stop. It also aids in stopping distance in many situations. The system uses wheel speed sensors at each wheel or sometimes inside an axle assembly. These speed sensors detect when a wheel has locked up and is skidding. It tells the computer this is happening and the computer commands the ABS unit to go into ABS mode. When active, the ABS will modulate brake pressure to the wheels and prevent them from locking up or skidding. When your ABS system has a problem, it often sets a code and illuminates a light on the dash. You pull these codes in the same way you would pull codes for a check engine light. These codes correspond to different failures in the system. Like check engine light codes, the code is just there as a guide to help focus your diagnosis; these codes should not be interpreted as a diagnosis.
ABS codes might not be accessible with some scan tools. You might need a special scan tool to pull ABS/TCS codes. In addition, ABS/TCS codes are specific to the manufacturer, unlike check engine light codes. For this reason, I'm only going to talk about these systems in general terms. For more specific information, consult your vehicle’s service manual. Here area few common questions about ABS:
- Do you need a scan tool to bleed ABS systems?
- In some cases, yes. Consult the service manual for your vehicle to find out if this is the case for you.
- If the ABS fails, will my brakes fail too?
- Not normally. The ABS system is designed to still allow the base braking system to operate normally if it fails. If your ABS light is on, your base braking system should still function fine; you just won't have any ABS in the event of a panic stop.
- Can an ABS/TCS failure cause a performance problem?
- Yes. The ABS/TCS system is tied into the engine management system. In some cases, the TCS can control the throttle and apply the brakes, which can compromise performance.
Once again, consult the service manual for your vehicle on the specifics for your vehicle and what the codes mean.