2004 Cayenne Turbo stuck in low range

[dpolson]

Just acquired a Cayenne Turbo and in testing out the systems, I put it into low range. Now it won't come out of low range. Switch appears to be working, as I get the message "must be in neutral and brake on" but even with those conditions met it will not come out of low range. How to fix? (I am 350 miles from the nearest dealer so I do all my own work.)

[wvicary]

Are the brake lights operating when you apply the brake? Have you tried restarting the engine?

[dpolson]

Yes and yes.

[wvicary]

If there are any LED light flashing at the selector switch that indicates an error in the system which you'll need the dealer scanner or after market scanner such as Durametric to read. I can only suggest checking all the fuses in both fuse blocks and having the system checked for codes.

[dpolson]

Precisely.The low-range LED in the selector switch is flashing. Interestingly, it will not lock the longitudinal any more, either. Here is the exact sequence of events:

1) received the car, shipped up from Florida (and grossly mis-represented by the seller on eBay). It was supposed to have the off-road technology package.

2) To test for the presence of the package, I went to see if it had a rear differential lock by activating the controls.

3) Put the car in neutral and applied the footbrake, actuated the control switch forward (the switch was initially physically stuck, no doubt gummed up with spilled pop or the like) but it freed up and worked, electrically, going into low range with first actuation, then locking the center diff with the second actuation, and doing nothing more with the third actuation. No rear diff lock! (Seller simply lied. Car has no metal skid plates or variable-rate sway bars, either.)

4) Then, moving the lever back, it unlocked the center diff, then on second backward actuation it threw up the "fault 4-wheel drive system" icon and the led flashed a number of times.

5) If one repeatedly moves lever backward, nothing further happens at all, unless one restarts the car and tries it again. Then the error message and flashing led happens again, as in #4 above.

My next step is probably to get a PST2 and attack it that way. But I would like to get some sense, before I go any further, of whether the problem is going to entail transmission removal (yikes) or simply replacement of the transmission control module. And in that regard, I don't know where that electronic module lives. Could someone please tell me? I have a Touareg shop manual on a Bentley CD, but I can't view it anymore because I upgraded all my computers to Windows 7 and it won't run on Windows 7!! (I need to get some XP-compatibility software and try that!)

Thanks for help!