Cayenne 955 Air Suspension fault
 

Dear gurus, please divide a minute of your time if you can give any advice.

I am not a professional mechanic, but try to do everything myself. So the better you describe, the best it would help me. Thank you all in advance.


2006 Porsche cayenne turbo s. I had it with air suspension error (Orange), but it was still working. During the trip across country (from Miami to Kansas, if that matters), red fault "Check Air Suspension" showed up and stays there all the time. Plug\unplug battery don't work. The car stucked in medium position. Today i went to work on my car in workshop, removed the compressor and during removal let all the air out. I checked the voltage on power cable - nothing. I threw a jump wire from car battery to pump - it starter to work. I checked the cable with 4 pins ( i guess it's control unit) it showed 4 and 3.8 volts on each pair, which if i am not mistaken is not enough.

I don't know how to troubleshoot further, but my stupidity lowered the car to the bottom. The car jumps on road as a wild frog. I'm not sure if it's wiring or control unit. Does any one have a hint or a wiring diagram? fuses or any other common issues? Please help me, i can't drive my car and have no idea how to diagnose it. The nearest dealership is like 350 miles away.

Here are the wiring diagrams:


https://cimg6.ibsrv.net/gimg/www.6sp...a9abb1be3f.jpg

Diagram 1

https://cimg7.ibsrv.net/gimg/www.6sp...0686124cda.jpg

Diagram 2

I circled the fuses. The big fuse - a 40A job that powers the compressor is located in the Ebox that is above the battery. There are a number of high-power fuses located there. Not an easy place to get to - since you have to tilt the seat back like replacing the battery in order to get to the fuse box.

Here is a blow up of that section of the diagram:

https://cimg0.ibsrv.net/gimg/www.6sp...4eb6e878b1.jpg

Closeup of fuses

The primary power line from the control relay (under the dash, above the pedal assembly I believe) to the compressor is the white/red one. Should be a hefty size wire.

I'd have to look at the suspension section of the manual - I know on the 958 there is a function for initial filling of the system, which on the 958 (which uses a sealed system unlike the 955/957) using bottled high pressure nitrogen. I'll see if this looks the same for the 955/957..

It's a bit different on the 955/957 - the springs are supposed to be pre-filled to 3bar (about 45 PSI) with argon gas before installation. The problems I see that you have are:

Unknown compressor condition - when you hooked it up to the battery - did the vehicle rise? I imagine with the ignition on it might unless the control unit is having a problem.

There are also a lot of warnings against lowering the vehicle with all the air out of the air-springs, that "folds" can form in the air-spring bags causing early/premature failure of them. If you can get the compressor working - I'd suggest finding some way of lifting the car as the airbags fill with air - so the folds can unfold without a lot of force on them. I can imagine this is a problem since the car is SO low that even getting 4 jacks under it will be a challenge. Harbor Freight has inexpensive jacks - 1.5 ton ones should be adequate - but you'd need 4 of them (meaning you'd have 6 ton lifting capacity total.)

As low as the P!G is - it would be difficult to impossible to get it up on a flatbed trailer without damaging something, due to the angle of the ramp for the trailer.

Dunno what to tell you. It's one of those impossible situations - damned if you do, damned if you don't. Sorry.. I'd upload the manuals diagnostics pages - but they're about 40 pages or so, and that would be excessive.

Good luck! Let us know how it works out.

Thank you so much! That's more then enough! I'm waiting for diagnostic tool to come to localize the issue. I will update topic when I will get some results.

I have another detail diagram for you - the compressor wiring. Note that several of the wires are signal wires that come from the control module.. and two are temperature sensor wires - that I assume read the compressor temperature to shut it off if it overheats from continuous use (where there is a leak..)


https://cimg9.ibsrv.net/gimg/www.6sp...11f07a6cd3.jpg

Compressor wiring.

The upside of your dilemma is - you can take some photos of your P!G with a wonderful stance. The wheels/tires really fill the wheel wells..

Well, thats for sure )))))


The motor worked when i attached it to battery when it was extracted from the system.

So far i checked the 40 a circuit under the driver seat (i only had one for some reason). I know that there was no power given from the wires, and if i'm not mistaken that's fault or a relay that is controlled by air suspension computer that gets some data from leveling sensors. So when i will get the code i could understand what's the real issue. At the same moment i've ordered a new relay since i've heard they sometimes caused the issues with pump.

Could be battery going out and causing issues with the unit.

I replaced my battery and then my Control Unit went out like you mentioned.

Ordered on ebay a replacement control unti from a salvage yard. Literally plug and play and right sided the issue. Porsche Cayenne Airbag ECU Steuergerät LUFTFEDERUNG 7L0907553E
( 201367975463 )
Here is an active module.
https://www.ebay.com/itm/2003-2004-P...ZZ8Lfw&vxp=mtr

I did chase fuses etc etc but not wiring.

I am almost at a year from the incident and the VW unit replacement has shown no issues.

i've just replaced battery, and I even checked it - it was fine. While waiting for durametric I ordered this computer just in case, but where is it located?

Thank you in advance.

How the heck do u read a wiring diagram. I’ve never been able to

So i fixed my suspension. Hardly anyone would find my solution helpful, but still. During the body kit installation we had to replace exhaust tips, but couldn't find the right one. So we had to hit the road without any. Guess what happened? exhaust melted wiring in the rear right side of the vehicle, where all the computers are. Had to cut and rewire all wires in that harness.