PaulW

I couldn't figure out what was wrong. Yesterday I spent 4 hours troubleshooting, the F125 switched tested electrically satisfactorily when unplugged in all positions, but when you plugged it in and put power to it.....it would not work, like it had a ground path in it.

Then I was driving the car last night to heat it up again and the speedo stopped working. That sucked.....plus it really affects how the transmission shifts and acts. So a new problem which was not related to the other problem.

Went over to Eddie's shop tonight, Gabor met me there.....he had a facelift F125 switch from an 02 transmission.....we unplugged my switch at the connector, plugged his switch in, and then I went from N to R, the indication stayed in N and the tranny in N until he manually moved the F125 switch in his hand to R, then everything worked. We checked it on VAG-COM, worked perfectly.

So about 1.5 hours later, the switch was changed out. Thanks to a lift, Gabor's knowledge and Eddie's tools.

So now onto the no speedo indication....I was hoping it would fix itself, but it didn't.

To make a long story short, the vehicle speed sensor is just forward of the connection for the F125 switch and the contacts were shorting to ground (or I should say providing a ground path so it would not operate correctly). It is a feed from the instrument cluster, to the vehicle speed sensor, then to ground. We plugged in another VSS that Gabor had and spun the axle, and it indicated speed on the speedo. We plugged and unplugged my connector about 10 times (or I should say I was in the car up on the lift and Gabor did all of this).....and then it started working again.

Here is the VSS at the 10 o'clock position:

<img src="http://www.audipages.com/Tech_Articles/auto_transmission/f1254.JPG">

The F125 wiring harness is the greasy one (this is not my car) just to the left of the arrow at 9 o'clock, it is disconnected in this picture, but it sits right below the VSS:

<img src="http://www.audipages.com/Tech_Articles/auto_transmission/f1255.JPG">

What do I think happened? I think that some cleaner got on the electrical connectors for both of these items that is conductive and when energized, provides a ground path which screws up the signal.

It's fixed. Don't want to do that again any time soon.

tozoM8

Clear codes, skip a few steps on the F125 switch replacement procedure, have some laugh, eat some pizza and the car is done. Good times....

Kneale Brownson

You mean degreaser your detailer used in the engine compartment got to those contacts from above during his "gentle" washdown?

PaulW

My engine bay was not greasy. It was pretty clean IMO. I'm not trying to put blame on anybody, just happy it's fixed, that I didn't screw up my transmission while the problem existed and hopefully others can learn from my experience and troubleshooting.

I would rather move on and maybe look at the incredible job Jon did on the paint and interior. Right now, I don't think I would ever have anybody detail the engine compartment of a car I owned again, but that could change.

pkrasusky

...it should happen to one of us poor schleps.

I'm with you - not a fan of underhood cleansing. Simple Green spray around light / spritz water remove / wipe clean.

Feels good when you:

<img src="http://www.azmortgageguru.com/wp-content/uploads/2007/12/dodge-bullet.png">

diogeniS8

Almost two weeks ago I took my S4 appart to change valve cover gaskets and cam adjuster seals, I just couldn't resist not to grab a couple of "engine brite" sprays and then the pressure washer to clean the engine from the leaks that had been going on for a while, (yea, under all those beauty covers it had to come to the point that I was smelling burned oil to realize that i had a leak)..... worse of all i run out of parts which I am still waiting to get, I hope I didn't f%^&amp;k up anything in there......oh God I hope it starts.... Tozo is a little bit far away from me

B5S4/C5A6

Definitely don't use degreaser. And it is for sure a gentle wash.

airbil

I bought the earlier model of this some years ago.
<img src="http://ecx.images-amazon.com/images/I/51pA-TAQWAL._SS260_.jpg"> (LINKED below ~)
Works great! Spread a pile of newspapers under the engine, spray some engine cleaner and/or simple green on a small area at a time and steam away. Using no attachments, it cleans areas that cannot be reached by hand. Did I mention that it works great?
For the final top secret short cut bling try:
<img src="http://www.meguiars.com/estore/productthumbs/product_G10900.jpg"> There's soooo much that could go wrong if someone pees on an electrical connection, I'd rather have dirty motor (and have often lived so) than risk encountering errors of unknown origin.
And that's all I know about clean motoring<ul><li><a href="http://www.target.com/gp/detail.html/601-2812799-6524101?asin=B000BQSJVK&amp;AFID=Nextag&amp;LNM=B0 00BQSJVK|Shark_Ultra_Steam_Blaster_S3325&amp;ref=t gt_adv_XSN10001">Shark Steamer $99</a></li></ul>

B5S4/C5A6

that is exactly what was done.

pkrasusky

...I'm even leary of doing the underhood 'my way'!

Great work btw, looks incredible!