A4 Abs problem

Hi there I have a 98 A4 1.9 tdi. Just recently I could feel a vibrating through the pedal my abs. So when the light came on when I was on the motorway I got the code which is 00290 which is left rear abs sensor. So I bought a new sensor and replaced it. Now I have just been out with it and I can still feel my abs through the brake pedal. My light hasn't come on yet as I haven't been on the motorway so no code has been stored yet. Anyone got any ideas what could be causing my abs problem. Thanks in advance.

Hi There, You are suffering from one of the most common A4 problems, had the same thing on mine.

If you have replaced the sensor:
1. Is it seated perfectly
2. When replacing it did you knock any dirt down onto the ABS ring
3. Is the ABS ring worn/broken

I had a bugger of a job getting mine out, but if yours wasnt to bad i would be tempted to lift it back out, check that there is no rubbish on the end of the sensor. Whilst in there get a torch and shine it down the hole for the sensor and see if there is any damage to the ring.

Chances are that the end of the sensor might have picked up a bit of rubbish as you were fitting it.

There are a load of threads on here about exactly this problem, good luck
Ron

I took the rear disc off when I did the abs sensor so I could see the condition of the abs ring it is very corroded but it didn't seem cracked when I inspected it. I also removed the copper seat that the abs sensor goes into and cleaned it all so it was perfectly clean. When I fitted the sensor it was catching the abs ring so I just pulled it back until it didn't catch the ring. I have also cleaned all of the other sensors and removed the bits off that were stuck to them. I suppose I will have to wait till my light comes back on and see what code I am getting.

If the ABS is triggering at slow speeds, you have a dull sensor. If you have VAG-COM (it sounds like you do) you can observe the wheel speed sensors at very slow speed and watch which sensor drops out first to zero whilst the car is still moving.

Thanks for your reply but I do not have VAG-COM I just have a generic fault code reader. It is only kicking in at slow speeds but when it is on the motorway the abs light comes on. I will just have to wait for it to come on and see which code it is now giving.