ABS activating at slow speed??

**rdguy** · 07-30-2008 07:26 AM

My abs brake system has been activating at slow speeds. It is an intermittent problem that does not happen everytime, but about every 5-9th stop.

Could this be a sign of contamination in the system or is it an electronic issue? Is this something I can trouble shoot or does it require an Audi Doctor?

98 A4 Quattro.
Rick

**whoace** · 07-30-2008 03:31 PM

Wheel speed sensor

**0000_a4** · 07-30-2008 03:43 PM

Try cleaning your abs sensor

**2001A4QUATTRO** · 07-30-2008 07:02 PM

They mean there could be metal particles on the abs wheel speed sensors. Take them out, clean them.

**rdguy** · 07-31-2008 05:28 PM

Thanks for the input, I have the wheel off, but don't want to pry and break anything. Does the ABS sensor come off the caliper or do I clean by taking off the rotor and going in that way?

Rick

**MattzWarsteiner** · 07-31-2008 07:26 PM

Remove the harness hold down bolt if any, then grab the shiny metal part of the sensor and pull firmly while twisting slightly. Don't pull by the wires and if you have grease on your hands or the sensor, clean both first.

**quattro16** · 07-31-2008 08:31 PM

Cracked tone ring on one of the axles.

**rdguy** · 07-31-2008 08:55 PM

With the wheel off and caliper off and even the metal sheild off, the wire comes througth the strut housing and the sensor is black and attached to the caliper. I don't see any lock ring holding it??

Is it a press in fit? 98 A4
There is a rubber boot between the caliper and the sensor, and flats on the sensor , but seeing as it is plastic I did not want to start wrenching on it for fear of breaking it.

**MattzWarsteiner** · 07-31-2008 09:44 PM

Does this car have brake wear sensors? That could be what you have found and I don't know those come out... so maybe find out for sure before pulling.

Mine ABS sensors are made of shiny metal and located right by the hub. They do just press in.

**rdguy** · 08-01-2008 05:18 AM

I don't think I have brake wear sensors. On the passenger side the sensor I found is at the front of the car side and the caliper is on the rear side. On my German made XR4Ti the brake wear sensors are a wire attached to the brake pad, but on the Audi that is not present.