yeldogt

My (early build) 06 S w/ 38K has been at the dealer all week for a host of issues -- mostly repeats. At this service and previous one a couple of months ago they have really gone the extra mile to try to get to the bottom of a few nagging intermittent problems.

They replaced the step motor in an attempt to eliminate an occasional dash warning that occurs (sometimes) after I have returned the car from the first reduction. But I also get the 25mph clunk/ thump downshift occasionally -- they think it is related - I have my doubts.

Can someone explain the function of the step motor

mudman2

which dealer ?

yeldogt

Now at CHP - NJ

Just to be clear -- this is the step motor in the transmission/ transaxle

touareg

This was on my 04 treg when I had it replaced, so could be a different one. A stepper motor rotates in precise increments, or steps, instead of free wheeling it like a regular motor. It can easily be advanced 3 steps and then reversed three putting it back to where it was before. The computer is able to control the center diff engagement / disengagement through the stepper motor.

When the stepper motor fails, the center diff does not disengage properly and causes jerky motion in slow speed tight turns and fast tire wear sometimes.

Of course Porsche doesn't use VW/AUDI parts (According to dealers around me) so you wouldn't have this problem. This was a common problem on early touaregs.

Dilberto

Did Porsche improve the later 955 motors?

wrinkledpants

There is a -C part number currently out. Older ones were -A. It's the same motor between the Treg and Cayenne, so I'd find one for a treg as they're cheaper.

This is the manufacturer PN, not the Porsche PN. AFAIK - there aren't any updates to the motor after this.

Dilberto

Did Porsche improve the later 955 motors?

wrinkledpants

I don't know what you mean by "later."

Dilberto

Is this the latest part revision?

0AD 341 601 C

wrinkledpants

Yes

Dilberto

Will the 2008-2010 Cayenne S/GTS/Turbo transfer case motors work?

wrinkledpants

Probably. If they're the same manufacturers PN. It's basically the same drivetrain as the 955. Same with the face lifted tregs.

Dilberto

Last question - is the motor same on V6 and V8?

wrinkledpants

I would guess so. I would not assume, though. Check the PN.