greasemonkey2824

OK so I work at a small independent shop were we work on all euro cars. I normally get all Porsche cars but they gave one to a new hire. It had a coolant leak from the tubes under the intake he replaced them and now the dang thing wont start. Its an 03 cayenne. I can not communicate with the Dme but I can with other modules and they all have a code for the dme. I have checked power and found that it only has 285 mv at the dme when I supply 12v with a jumper I still can not comm. Does anyone out there have any ideal on what it could be or were to go next. I have a feeling that its gonna be something simple cuz it ran before the work.

Also when trying to start it says that my foot is not on the brake when it is and Psm failure

Blunterbryn

Does anyone else read this and think, that's exactly why I take my car to Porsche dealership?

RayBarham

I'm in the same boat no and I'm pulling my hair out! I soldered all the splices, checked fuses and still no crank. I get the PRND all lit up.

phatz

I think car flipper when I see zero day posts

RayBarham

I'm in the exact same boat and I'm at my wit's end trying to figure out what the solo could be.

koiboi

I have a 2004 Porsche Cayenne S 4.5 and recently JUST managed to figure out a solution to this problem. I checked the fuse box located by driver side and lifted up the fuse holders (there should be clips that hold it in place). Found a broken red wire that connected to pin 62 of the DME. This red wire was spliced to fuse number 15 (10A) and terminal 86 of the main DME relay. Once the splice was repaired, everything went back to working order.

RayBarham

Man! I'm glad you got it figured out! What were the symptoms you were having?

RayBarham

it took me this long to realize what you meant by this post. LOL. To respond to that, the sheer fact that I only own this car for about 4 days before it gave me a no crank no start, would make me wish that I would have flipped it. LOL

MO_Money

Man I have 2006 Cayenne right now with the exact same symptoms and IT HAS BEEN KICKING MY *** ALL WEEK! Pin 62 at the DME is “permanent terminal 30 power” as per PAG wiring diagram so that makes sense.
I’ll have to check all my wires down there Tuesday since mine is most likely a corrosion problem in the harness on this POS

RayBarham

I thought I had double back around to give an update. So after having decided, internally, that I could not possibly do any more damage to this car than I already has been done, I went out to my driveway and cut half the fuse box off so that I can get access to the bottom of the fuse box. As soon as I flip the fuse box over, I saw a puff of smoke and noticed that one of the wires had oxidized and was no longer connected to the underside of the fuse box. That wire was actually the power wire that ran to the DME. So when I inspected it above the fuse box, and the dealership inspected it above the fuse box, and two other independent shops inspected it above the fuse box, no one would have been able to see that that wire was barely hanging on. Long story short, it took me off 3 minutes to get that wire stripped, a new one ran and soldered. Then the car fired right up!

It sat in my drive for 3 months, at repair spots for an additional 2 months all over a single wire! I hope that you can get that fixed pretty quickly and that the next problem you have is not the problem I'm having where I have the scored cylinder and now I have to replace the whole engine.