It doesnt happen all the time, at least when Im driving it. My wife complains about it, alot.
The ABS light is not on or flashing… I had the module rebuilt by module masters right after I got it 1.5 years ago. This issue started in the last month or so.
Im suspecting an ABS sensor ring or sensor. I tried to scan them with vag, but it seems to lock up as soon as you hit 20mph (or something like that). The time during which I did watch the speeds they were identical. Of course the brakes never pulsed during this time either.
Im going to pull all the wheels tomorrow and inspect all of the rings and sensors, but if anyone has any thoughts or suggestions Im def open to them.
i think you’re on the right path. take someone else for a ride with you so they can watch the scanner. Does vag offer realtime scanning or is it delayed?
ya I notice vag wont let you watch the sensors over a set speed. keep it under and watch them. or if the car is not running and ignition is on you can watch at any speed.
I put the car on a lift (or jack it up if lift not available) and watch each sensor as you spin the wheel by hand and then stop the wheel quick and watch.
use vag com, and watch the sensor readings when it’s happening, you’ll catch one drop to zero. next is to jack it up, zap out the axle bolts and slide the outter joint in so you can find the cracked ring. rear rings crack first, front sensors typically get “rust crushed” and fail first. here’s a cracked ring on the rear of an A4. Avants seem to do this more often than sedans, not saying that sedans don’t do this. the only reliable source for Avant axles is Raxles. Avant axles are different, you will get fucked getting one from napa, awful zone, ect. they’re $250is a crack, and the rings aren’t available separately and joints alone are $300, it makes no sense, i know…
well I couldnt catch the issue while braking under 20km/hr. However, I noticed alot of small spiking in the left rear sensor, it was the flakiest of the bunch.
Sure enough I pulled back the left rear axle and its cracked, JUST like in the picture above. ugh. The other rear one looked great. I guess not so bad for a car thats been in NY its whole life with 160k miles.
Im half temped to try to get the ring off, cleaned up and weld it back on… lol
So I slid the broken ring off, cleaned up the rust, grooved and welded the backside, ground it down round. Then cleaned up the axle slid it on and tacked it in 3 spots.
Monitored the sensors with VAG and the spikes seem to be gone. WIfe took it out for a 10 min drive and it didnt pulse once on her. Only time will tell if its really fixed.
Just got off the phone with my wife. She said the brakes didnt pulse once on the way in. Usually its good for at least one or two. Seems like a win so far still.
Awesome on the fix. My A4 wagon is acting up as well. if you try and stop on that loose dirt/gravel at the end of a driveway, if you even tap the brake pedal, it locks the left front wheel. I’ve got to get my head in there and look at it. My ABS light has been on for about 2 years now, suprised it hasen’t burnt out by now.
