XcellR8edAudi

i don't mind the no abs, and i don't mind hitting the switch each time, but it would be nice not to worry about it at all, people said to remove the ABS control unit relay. i know this is inside the car at the driver's knees, i see the relays up in there, not sure which one it is tho. the diagram shows the middle row, first one on the left. anyone know if it's the one with the relay in it? part number? thanks.

audi-bahston

I have the same problem with my car... The warning light is wicked annoying. I'd like to fix it also. I was told it might have to do with the ABS sensor. Let me know what you find out.

kevkirz@yahoo.com

RussB

If you're comfortable with an Ohmmeter, you can do a quick sensor continuity check. (They should each be ~ 1200 Ohms.) Easiest point to access all four sensors is at the large harness connector that plugs into the ABS controller beneath the rear seat. You'll need a schematic diagram for the connector pinout.

Beyond a DC measurement, if you have access to any old oscilloscope, you can test the sensors' sinusoidal outputs with the car on jackstands and car in gear. Their outputs should be within ten percent or so of each other.

I've found broken sensor wires as well as sensors that test okay with the DC Ohmmeter but for some reason don't produce a reliable sine wave output. That's the extent of my ABS troubleshooting.

HTH,
Russ Bellew

auditech1218

ive seen a bad ABS switch sometimes make the antilock activate when coming to a stop like if you were on ice, if thats the problem your having try removing the ABS switch, start the car and the ABS will be ON (light off)unless theres a control unit fault or the fuse in the ABS relay is blown. Try driving the car and see if the problem went away. heres the answer to your original question but please try what i said :-)The ABS relay is in the Auxillary relay panel, it has a 76 on it with a 10 amp fuse in the top.

pureroundcircle

in my case one of my front wheel speed sensors was too far from axle gear thing. When you get a new abs sensor they are supposed to have a melt away end tip on them or something and you are supposed to place them against the gear to get them at the correct distance. (or so i was told) I just pushed my old one in all the way and then backed it out just a hair. I think they just got out of adjustment a bit.

mint875000cstq

BTDT -the little "melt away" caps are very easy to replace...Audi Part # 437 927 809. About $3 ea. at WorldImpex or $4-5 at dealer. Just loosen the allen screw on each wheel,remove the sensor, remove crusty , old white plastic 'caps', clean the sensor tip really well, attach new cap, push sensor back in as far as it will go , tighten allen screw. All problems solved until caps gunk up again or axle splines that read the signal rust out. :-)

-aaron
1987 5000csqt 280,000 miles

audi-bahston

My warning light blinks the whole time while I'm driving the car... do you think this plastic tip soulution will work in my case?

SteveAngry

if you don't want to deal with the ABS on/off.

Steve
Michigan

RussB

Maybe. Maybe not. Perform DC resistance test of all 4 sensors first.