2004 Cayenne Turbo issues-- need help

[dpolson]

Acquired a 2004 (I know, bad year) Cayenne TT with numerous undisclosed problems. Have a PST2 on the way to help diagnose. While I'm waiting for it to arrive, any thoughts on the following issues would be appreciated.

1) (see partial remedy below in next post) Stuck in low range. Switch operates, but low-range (square) LED flashes and "four-wheel-drive system fault" appears on dash. Does the failure-prone motor that activates the center differential lock also activate low-range, or is there a different actuator for that, perhaps in the transmission itself? Or is the controller box likely at fault, and if so, where is it physically located?

2) Both secondary air pumps are shot. Will replacing these likely also cure the catalytic convertor and O2 sensor codes that may be downstream effects of the shot air pumps? (P0491 and P0492 for the pumps, P0421 and P0431 for the cats, and P2187 and P2189 for the O2 sensor readings.)

3) Rear hatch glass window will not open. Is this more likely the microswitch on the wiper base on the glass, or the lock mechanism in the hatch? Will the PST2 tell me which?

4) Everything that has a push-to-open and push-to-close latching mechanism is stuck-- cup holders, storage drawers in front and rear consoles.. Any point in replacing these or will they just break again? Has design been improved?

5) When the O2 sensors wear out, will they throw a code indicating need for replacement? Car has 124,000 miles and unknown if they have been replaced. Looks like they are really hard to access.

6) Where can I find the best thread for describing how to replace the factory PCM/Bose unit? There is a CD stuck in it, the nav is non-functional anyway, and the system turns on and off at random. Might as well trash it and put in a Kenwood nav unit with rear-view camera! I realize I will have to bypass the MOST system and re-wire the car.

Many thanks!

Edited May 2, 2012 by dpolson

[dpolson]

OK, folks, I have begun to solve question #1 above reagarding the stuck transfer case (since I could find nothing relevant in this or the Touareg forums) by monkeying around under the car. Here is what I have learned:

Yes, the stepper motor on the transfer case controls BOTH the going in and out of low range AND locking the center differential.

I figured this out by attemepting to swap the known good motor from my V10 Touareg (which is shaping up to be the far better vehicle between the two) to the Cayenne Turbo. I took it off the Touareg when it was in high range. When I went to put it on the Cayenne, I could see that the shaft keyway was not going to align with the motor's keyway (sicne the Cayenne was stuck in low range), so this is how I knew that this stepper motor controlled hgih and low range. I had to grab the shaft coming out of the transfer case with some channel lock pliers and rotate it counterclockwise (looking toward the shaft) about 90 degrees and lo and behold it clunked into position to line up with the stepper motor. So, figuring the good motor from the Touareg would operate everything just fine, I lowered the car, fired it up, (no more fault light and hgih range working now) and operated the switch to put it in low range, lock the diff, unlock the diff (so far so good--no warning lights), and.... it would not go back into high range. Warning light back on. Stuck again, even with the good stepper motor. So.... back up on the lift, remove the stepper motor again, rotate the shaft manually with the pliers counterclockwise into high range again, rotate the motor shaft to align, and bolt it all back up. I'm afraid to try it again. One thoguht I had is that it is just stiff from lack of use (prior owner didn't use low range, it seems) and that after these couple of manaul movements it might work eventually. But I'm too tired to try it again and go through the above process again right noiw. I think I'll look under the passenger seat instead and see if there are any wires amiss.

So... I still don't know why the Cayenne won't operate the stepper motor from low to high range, but it operates it fine in every other operation. Next stop: the control module under the passenger seat and its attendant wiring!

Useful lesson: stuck transfer case can be unstuck manually. Taking the stepper motor off is really easy. Three 10mm-head bolts and two 8mm-head bolts. Two wire connectors. One pair of big channel locks or vice grips with good teeth to engage the splines on the shaft without damaging them.

[2GOFAST]

.

6) Where can I find the best thread for describing how to replace the factory PCM/Bose unit? There is a CD stuck in it, the nav is non-functional anyway, and the system turns on and off at random. Might as well trash it and put in a Kenwood nav unit with rear-view camera! I realize I will have to bypass the MOST system and re-wire the car.

I have replaced the PCM with a kenwood head unit, back-up camera, etc. Not that hard to do. I used a MOST-HUR to interface the Kenwood unit with the fiber optic ring and the bose system. Do search for MOSTHUR or MOST-HUR. can also seach youtube for videos.

[hahnmgh63]

Rear O2 sensors are fairly easy to replace as you may already know after crawling under the Pig but the fronts are a bit more difficult. They will throw a code when they get to a certain point of failure but they will slowly fail to react properly over time and give poor readings to the ECU before they completely fail. If your Fuel Economy is fairly good, for a pig, then I wouldn't worry about them for now as you've got plenty of other problems. I would pick up a bottle or spray can of a good contact cleaner/enhancer (such as Stabilant 44 from the VW dearler for ProGold (Amazon?)) and go through every connector above and underneath the vehicle and spray on all connections and reseat them, clear the codes and drive and try everything again and see what comes back. This solved a couple of Electrical faults I got when I got my '06 Turbo S.

[thewhirls]

OK, folks, I have begun to solve question #1 above reagarding the stuck transfer case (since I could find nothing relevant in this or the Touareg forums) by monkeying around under the car. Here is what I have learned:Yes, the stepper motor on the transfer case controls BOTH the going in and out of low range AND locking the center differential.I figured this out by attemepting to swap the known good motor from my V10 Touareg (which is shaping up to be the far better vehicle between the two) to the Cayenne Turbo. I took it off the Touareg when it was in high range. When I went to put it on the Cayenne, I could see that the shaft keyway was not going to align with the motor's keyway (sicne the Cayenne was stuck in low range), so this is how I knew that this stepper motor controlled hgih and low range. I had to grab the shaft coming out of the transfer case with some channel lock pliers and rotate it counterclockwise (looking toward the shaft) about 90 degrees and lo and behold it clunked into position to line up with the stepper motor. So, figuring the good motor from the Touareg would operate everything just fine, I lowered the car, fired it up, (no more fault light and hgih range working now) and operated the switch to put it in low range, lock the diff, unlock the diff (so far so good--no warning lights), and.... it would not go back into high range. Warning light back on. Stuck again, even with the good stepper motor. So.... back up on the lift, remove the stepper motor again, rotate the shaft manually with the pliers counterclockwise into high range again, rotate the motor shaft to align, and bolt it all back up. I'm afraid to try it again. One thoguht I had is that it is just stiff from lack of use (prior owner didn't use low range, it seems) and that after these couple of manaul movements it might work eventually. But I'm too tired to try it again and go through the above process again right noiw. I think I'll look under the passenger seat instead and see if there are any wires amiss.So... I still don't know why the Cayenne won't operate the stepper motor from low to high range, but it operates it fine in every other operation. Next stop: the control module under the passenger seat and its attendant wiring!Useful lesson: stuck transfer case can be unstuck manually. Taking the stepper motor off is really easy. Three 10mm-head bolts and two 8mm-head bolts. Two wire connectors. One pair of big channel locks or vice grips with good teeth to engage the splines on the shaft without damaging them.

Are you any further forward with the stepper problem? I have a cayenne which disengages drive completely in the transfer box whilst moving.

[clarksongli]

was 2004 really that bad compared to other years? i've had basic stuff go wrong (battery, coolant pipes, hatch struts) but nothing major. I do maintenance at almost 1/2 the interval (all diffs/TC/AT at 75K). Oil change every 5K....

for the rear hatch glass...i'm curious to know, press and hold the trunk button on the key....see if that opens it. If it does then you know it's the little button on the glass.

Stuck cupholders....mine were stuck too when i got it.....i pull them out, cleaned them up and haven't had an issue since.....i think people just spill crap in their car and never try to clean it up. But to answer your question....no the design hasn't changed.

knock on wood....my CTT has been good to me

[ekstroemtj]

Rear O2 sensors are fairly easy to replace as you may already know after crawling under the Pig but the fronts are a bit more difficult. They will throw a code when they get to a certain point of failure but they will slowly fail to react properly over time and give poor readings to the ECU before they completely fail. If your Fuel Economy is fairly good, for a pig, then I wouldn't worry about them for now as you've got plenty of other problems. I would pick up a bottle or spray can of a good contact cleaner/enhancer (such as Stabilant 44 from the VW dearler for ProGold (Amazon?)) and go through every connector above and underneath the vehicle and spray on all connections and reseat them, clear the codes and drive and try everything again and see what comes back. This solved a couple of Electrical faults I got when I got my '06 Turbo S.

May i ask you please if it is not in some way dangerous to spray all over this electric components or i missunderstood your advice?!Are you talking about some di electric grease or liquid?Thank you

[hahnmgh63]

The ProGold is available in a squeeze tube or aerosol spray can. I spray it on the electrical connector contacts in the electrical plugs. Do a Google search, Pro Gold is very popular in the high end electronics industry. Stabilant 44 is another matter. Sounds like it is so good that it is magic, but they also charge an arm and a leg for it. Stabilant 44 is available from VW/Audi dealers but definitely not cheap. A Google search of either brand will reveal nothing but positive performance feedback.

[deilenberger]

Interesting, the stuff I have (BMW recommended for the same uses) is Stabilant 22. It's sold at NAPA stores in the US as CE1 (Contact Enhancer-1) for a small fortune. Luckily the 10cc bottle you get for a bunch of money will about last your lifetime if you don't try drinking it. It only takes a tiny dot of it for it to work it's magic.

BTW - if you Google Stabilant 44 - Google returns all references to Stabilant 22. Just thought I'd try to avoid confusion on what might be used.

Info on it:

http://www.dewitzdiagnosticsolutions.com/review/stabilant-22a-snake-oil/

http://www.stabilant.com/appnt20h.htm

It's one of the few items like this where I've never seen a negative review of it, and it's widely used in audio work for very low signal voltages.. (like magnetic LP cartridges - mV range..)

[hahnmgh63]

deilenberger is correct, I just went out to the shop an it is Stabilant 22. And I haven't purchased any for a few years so maybe it can be found cheaper nowadays. I believe it is manufactured in Canada.

Here is a good Pro Gold / Deoxit description. Keep in mind this is pretty much an ad from the manufacture too:

http://store.caig.com/s.nl/ctype.KB/it.I/id.1977/KB.215/.f

Edited January 8, 2013 by hahnmgh63

[ekstroemtj]

Thank you very much for all the information.