Wheel speed sensor question

[ScottArizona]

Some of you may have seen my posts about my tiptronic acting up. I've got the car back from the mechanic for a few days before I return it and I want to trouble shoot a few things before it goes back for more diagnostics.

In researching this problem I've found some people have experienced bad shifting when a wheel sensor was sending bad data (i.e., it was not broken, and did not therefore throw a code...it just sent wrong information that was enough to "confuse" the tiptronic transmission). The suggestion was to clean the sensor of brake dust and see if that helps. Can someone tell me where I can locate the sensor (a picture would be great) and the procedure I should use to clean it? Should I hose it down? Use electrical contact cleaner? disconnect it first?

Also, I want to verify that I don't have a bad wheel bearing that could be exerting drag on a wheel, as this MIGHT also contribute to bad shifting. How do I check to if the bearing is bad? I do hear a groan coming from the rear fo the car at times, but it is definately not consistent and only seems to happen at low speeds in fourth gear (especially when cold), and on hard right turns, but it always goes away quickly and is by no means constant or cyclical.

Last question: where is the abs control unit. I have noticed my abs kicking in early and abruptly as of late, and I am wondering if all of my problems might be related. If the unit is near the battery, it could have been damaged by water as I noticed about a month ago that I had a plugged drain hole that permitted water to pool after rains and washing.

Thanks so much for your input. Scott.

Edited January 4, 2007 by ScottArizona

[Loren]

For MY99

1. Control module

2. Relay

3. Fuses

4. Speed sensors

5. MILs and information lights

6. TC (OFF) rocker switch with light

[Loren]

Part 2...

Because of your water damage you may want to check these ABS ground points too.

Ground point 2 = The ground point is located on the left in the luggage compartment

Electronics ground = The ground point (arrow) is located on the dashboard support frame (A)

[Izzy]

Scott, you got mail.

Izzy