ABS Light / Bleep

[C9CRM]

Got my module back in the week and have fitted it back on this morning, all sorted, no lighs or beeps!! Well done BBA Reman!!

[Marshy]

Well, this is timely... A few days ago I started to get some really odd symptoms, which I've crudely chased down to either the ABS module or the sensors from which it works.

Symptoms:

- short (sub-second) pulsing through the brake pedal when braking at slow speeds
- occasional full on ABS intervention (new trousers please!) when braking gently at slow speeds. Very occasionally I could swear I heard the pump pulsing for a few seconds when I didn't have the brakes applied at all, but since the car was moving more quickly and the noise levels were higher, I can't be sure)
- slight drivetrain shunt once off the throttle and <2000 rpm (like it can't decide how much fuel/air to supply to the engine)
- relay clicks from under the dash, at the same time as above.
- at any speed, sometimes there'd be a relay click accompanied by a slight flicker of the (Xenon) headlights

So, taking 2 and 2 and coming to 4 (+/- 1) I decided to disconnect the ABS module under the bonnet to see what difference that made. Apart from turning the dash into a Christmas tree, all the above went away.

I'm guessing module or sensors, but don't know where to go from there to chase it down further. I'll hit the search again before begging for help. I know there are some measuring blocks somewhere for speed sensors, so I'll see if I can't get some joy there first.

On the upside, I can comfort myself thus: I once had a five litre TVR for a couple of years, with no traction control and no ABS. That didn't kill me, so I'm pretty sure the S4 will be fine without for a little while. Better that than random ABS...

[spookymatt]

wonder of any of you guys can help me out too, suffering similar probs, ABS seems to kick in at very low speed, just before you come to a stop.
Had the ABS sensor replaced and has made the problem a little better but not solved it.Only had the car a couple of weeks and not really got to enjoy it yet.
Someone has mentioned a cracked tone wheel but I can't find any information about that on the web.
Any advice would be greatly appreciated.
Thanks in advance

[Blue_Thunder]

There is an ABS sensor on each hub.

Have you run Vagcom on it to see which (if any) are throwing up fault codes?

[spookymatt]

My local specialist has had the car in for a week, he's fitted a replacement ABS sensor on the wheel we thought was causing the problem, he's finding no fault codes. He has also checked the tone wheel as we thought this might be causing the problem.
I guess it needs to go into Audi themselves to see what they can find...