YukonLT

Hey Guys,

The A4 I recently purchased has the ABS issue that I have read so much about. I have been reading, and searching, and reading some more...to no avail. Here's the scoop, the car has had the module replaced, and has a new wheel speed sensor. So, theoretically it should be fine! But it isn't...

The ABS light only comes on sporadically, and at random times. I can drive 100 miles and have no issues, then the next day it will come on leaving the driveway...completely random. When the light isn't on, the pedal pulsates like it's trying to activate the ABS, but only at lower speeds, and definitely follows the rotation of the tire. It gets slower as the car slows down. The guy I purchased the car from was meticulous about maintaining this car, but he moved onto another vehicle and just gave up trying to fix this because he wasn't driving it anymore. He actually gave me another brand new wheel speed sensor with the car.

When the light comes on and I check it with VCDS, it tells me it's the left rear wheel speed sensor, but that's that brand new one! So, right now I'm at a loss and don't know how to proceed with diagnosing it. ANY INPUT would be greatly appreciated!!!

Thanks!

YukonLT

I know this has been discussed countless times, but nobody has any advice on the next step?

logicalloonatic

make sure its exactly where its supposed to be, if its off by mm's it wont read. try swapping sensor with a known good one, coulda got a bad one out of the box. check wires leading to it

Prospeeder

Remove the sensor, and turn the axle, and watch the little teeth, if any of the teeth are damaged, this will happen. Had the exact same thing on my A4, and one tooth was damaged from a rock or something not sure. Replaced the axle and yay ABS worked. I too had the module rebuilt only to find out that there was more stuff wrong with the ABS.

Although they may have fixed it by now, its been months lol. Or gave up and unplugged the module again.

Lehighosprey

When I hook up my code reader it doesn't connect to abs.The reader is able to read engine.Dropped knee panel and checked pins on male end all good.
Just did entire suspension and brakes rotors and wheel sensors .Any ideas