When the ABS warning light comes on it means there could be a problem with your anti-lock braking system(ABS). ABS prevents your vehicle's wheel from locking up in a sudden stop which helps avoid skidding out of control especially on wet roads
Though sometimes it could also be the result of a fluke in the ABS system, so when this light comes on and you are driving ' don't panic' find a safe place to pull over, turn off your engine, and then restart the car. If a fluke in the ABS system triggered the warning light, it should turn stay off when you restart the engine but if not, then it's time to get an ABS diagnosis
The most likely reason is failure of wheel speed sensor(WSS) or an issue with sensor's wiring circuit as these will disables the ABS system and causes the ABS warning light to come on
To check the wheel speed sensor you have to measure it's output voltage, you do this by plugging a breakout box into the ABS module's wiring harness and attach the test leads from a digital volt ohm meter (DVOM) to the appropriate pins for the WSS circuit. For a proper wheel speed sensor, an alternating current (AC) voltage reading of 50 to 700 MV is produced when the wheel is spun by hand at about one revolution per second-- but if you have no reading or a low voltage reading then you have to measure the resistance in the WSS circuit. The resistance should be around 800 to 1400 ohms. If there is too much resistance in the sensor circuit, reads open or is shorted (little or no resistance), then measure the resistance across the sensor itself. If the sensor itself reads within specs, the problem is in the wiring or connectors. If not, then you have a bad sensor that needs to be replaced
DRIVING WITH ABS WARNING LIGHT ON
If no other brake system warning lights are on, it means the ABS brake system may not be working, but there should be normal operation from the standard service brake system. It should be safe to drive to a shop as long as you keep in mind that in the case of a sudden stop, the car is more likely to skid or slide.
If there are other brake system lights on in addition to the ABS light, then there could be something wrong with the basic service brake system. It could be something very serious like a hydraulic problem or loss of brake fluid pressure. In this case, IT IS NOT SAFE TO DRIVE
The most likely reason is failure of wheel speed sensor(WSS) or an issue with sensor's wiring circuit as these will disables the ABS system and causes the ABS warning light to come on
To check the wheel speed sensor you have to measure it's output voltage, you do this by plugging a breakout box into the ABS module's wiring harness and attach the test leads from a digital volt ohm meter (DVOM) to the appropriate pins for the WSS circuit. For a proper wheel speed sensor, an alternating current (AC) voltage reading of 50 to 700 MV is produced when the wheel is spun by hand at about one revolution per second-- but if you have no reading or a low voltage reading then you have to measure the resistance in the WSS circuit. The resistance should be around 800 to 1400 ohms. If there is too much resistance in the sensor circuit, reads open or is shorted (little or no resistance), then measure the resistance across the sensor itself. If the sensor itself reads within specs, the problem is in the wiring or connectors. If not, then you have a bad sensor that needs to be replaced
DRIVING WITH ABS WARNING LIGHT ON
If no other brake system warning lights are on, it means the ABS brake system may not be working, but there should be normal operation from the standard service brake system. It should be safe to drive to a shop as long as you keep in mind that in the case of a sudden stop, the car is more likely to skid or slide.
If there are other brake system lights on in addition to the ABS light, then there could be something wrong with the basic service brake system. It could be something very serious like a hydraulic problem or loss of brake fluid pressure. In this case, IT IS NOT SAFE TO DRIVE
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