Steveo369

I've been having some occasional issues with what I think is ABS kicking in too early, and I *think* it's coming from the right front. It may actually not be coming from that wheel, but it sounds/feels like it's coming from that wheel. It may actually just be due to the location of the ABS pump that I think it's coming from there...

Is ABS wheel-independent, or does it activate all wheels together? (or some combination, such as diagonal or both fronts, etc)??

The right front wheel was curbed about 4 years ago, pretty hard. I've replaced all the front control arms and installed sport suspension, but the 'problem' persists.

The issue is noticeable under hard braking and also at the track. ABS just seems to kick in way too early. (but it may actually be just the way I brake; perhaps I'm stabbing too much). It's never affected driveability, but can be annoying & is a bit worrisome.

Anyway, I'm swapping out winter tires next weekend, bleeding the brakes, and doing other routine spring maintenance, and though that maybe I'd swap ABS sensors R/L and see if the problem appears to change at all.

Other possible ideas that I think it could be are:
Corner weight. Perhaps for some reason the front right suspension is slightly 'tweaked', resulting in less weight at that corner, and the tire wants to lock up easier.

Out of round knuckle/bearing. Perhaps the shaft where the ABS pickup is is slightly damaged, and shifts under hard braking, resulting in a false positive for the sensor. I've not had any bearing noise from that corner...

Damaged ABS sensor. From what I've read here, this usually will flag the ABS light, and will result in loss of ABS, not overactive ABS

Damaged ABS pickup ring on the shaft. Maybe missing teeth? I'd think I'd see issues with every brake application if that were the case.

Anyone have any other ideas? Maybe I'm just too paranoid and a brake stabber, and it's all in my head.

Carson (K03x2)

They are magnetic sensors and will pick up rust and other loose metal particles, which reduce their effectiveness. Cleaning them usually resolves the issue you are having. If it doesn't, that is when I would go further into it.

Steveo369

last summer when I did my suspension.

Now that I think about it, one of them (the right one) did have very minor abrasion/dent on the face....

That strengthen's my case. I want to swap them to see if the problem switches to the other side, if that's possible.

Are the speed/ABS sensors the same? Can they be swapped R/L?

Yippers®

Etka says same same

Steveo369

Hopefully a swap will identify a bad sensor, like swapping coilpacks.

I figure ABS parts are expensive, though I haven't priced a new one yet.

Yippers®

To give you an idea the 99.5 sensor for use with brakes that have wear sensor pads are part number 8D0 927 803 D ... europartsdirect or worldimpax show between 95 and 155 depending on which manufacturer Meyle or Febi ...
That is an ouch.

Steveo369

You got me a bit confused.

The ABS sensor slides directly into the knuckle, (I thought) fully independent of the brake caliper and pad wear sensor system.

I know Audi/ETKA and logical part numbers aren't known to go hand-in-hand, but you're saying that the ABS sensor is different for the 99 and 99.5+ cars?

Yeah, I figured the ABS/wheelspeed sensor (assuming that we're talking about the same part) was pretty damn pricey... Hence my desire to do troubleshooting prior to purchasing.

Yippers®

to give you at least one part number to use for internet pricing look up to gauge how much pain there would be.

I subsequently looked at other MYs and the break over appears to be at 99.5. The part for prior years is listed as 8D0 927 803 and makes no distinction about wear indicators. There is also a screw in part listed at MY99.5> for the APB. Only the w/ wear indicator part number shows in my copy of ETKA so I've no idea why they even reference the wear indicator. HTH