abs and asc warning lights

Both of these warning lights have suddenly lit up on my 523i 1999 manual. This has coincided with the brake fluid light coming on. Will adding brake fluid resolve all issues?

Reply to
steve wells via CarKB.com
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Perhaps, but probably not.

The two systems are controlled by speed sensors mounted on each wheel. My guess is one of the sensors on the rear wheels has gone bad.

Reply to
Jeff Strickland

Brake fluid light probably equals serious problem.

Neither ABS nor ASC can be relied upon to work while your brakes are potentially ineffective.

You need to find out where your brake fluid is going (other than down due to pad wear), rectify whatever the problem is and then see if the other lights go out.

Reply to
R. Mark Clayton

Thanks for your replies. I have also noticed that cruise control is not working either, is this related

Reply to
steve wells via CarKB.com

Probably.

The Brake Fluid warning is probably not related to the ABS and ASC, but should not be ignored. The ABS and ASC are controlled by speed sensors, and if the speed sensors are not working, the Cruise won't work either because it uses the same speed sensors.

Since the ASC is looking at speed sensors on the rear wheels only, then my guess is that you only need to look at the rear axle to solve your problems. The speed sensors are physically located out at the hubs where the brakes are. They are each held in by a single bolt, and have a wire that goes to a connection point that is near the centerline of the car. You may find physical damage to the wires leading to a sensor, and this will be a dead give away as to the problem, but the sensor itself can fail internally, and this is more difficult to diagnose. The car's data port should be able to tell which sensor is not working.

Reply to
Jeff Strickland

Thanks for you advice, Jeff

Reply to
steve wells via CarKB.com

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