bnwa

Thank you all for your help.

My 2008 Cayenne S with close to 200k miles is having strange symptoms.

all problems started to show up last week.

1 - Systematicaly, when starting the engine I get an Abs failiure and strangely It's happy to remind it like every 5 minutes (when breaking or not...)
2- it will also launch a psm failiure right away and disable psm.
3 - will some time stall backing out of the driveway, or idle with some hickup for 10 secs. no more.

Never the less the car dives fine and does not feel in limp mode, actually shifting gear later than usual, something like 1k rpm higher. (Kinda like it...)

Air suspension leveling wont work, "accumulating pressure" message, changing level only worked going down. ( checked tank pressure by filling tires and no pressure available).

As of yesterday, brand new fully charged battery.
Some info since with my durametric:

errors: multiple cylinder misfire, unable to acces porsche stability module... and some lights to replace and air cond. open circuit error I have been getting for 4 years now.

cannot connect to psm... is the module dead? Is it controling level system (compressor?)

Decided to try to launch level control module an ran diagnostic...
compressor ran.
front of the car rise = ok
back of the car rise = ok

after unpluging all, started the car, decided to lower the car from std to low, releif valves oppened (ptffffffff) and the car reached the low position.
decided to raise it to std.... pressure accumulating message.

I feel there is a challenge here.

Any pointers will be appreciated

bnwa

Here is additionnal codes i'm now getting with the durametric short test.

Someone knows what all those C errors are linked to?

Short Test
Siemens Digital Motor Electronics SDI4
Current Fault Codes

0016: Lost communication with brake system control module Upper limit value exceeded
0456: Evaporative emission system leak detected (very small leak) Upper limit value exceeded
C146: No signal/communication
C121: No signal/communication
C103: No signal/communication
C164: No signal/communication
C212: No signal/communication
C126: No signal/communication
C114: No signal/communication
C111: No signal/communication
C418: Upper limit value exceeded
C155: No signal/communication

1528: Ambient temperature via CAN Upper limit value exceeded
1552:Function monitoring: control unit fault, group a Implausible signal
2181: Cooling system performance Implausible signal

deilenberger

Given the wide variety of symptoms you're experiencing - I'm taking a WAG that there is a communications problem with one or more of the computer buses in the vehicle.

Has the drivers side or passengers side footwell ever been flooded? These vehicles are know to do a lot of bizarre things and throw a multitude of codes when the wiring harnesses that go through the two footwells are destroyed by corrosion caused by repeated flooding.

People have fixed them by splicing in good sections of wire - but it's not a trivial job - and would best be done by someone with some real electronics knowledge.

bnwa

Thank you very much for your help.

Went in to check for signs of flooding in both footwells, but did not find any evidence of past or current water infiltration.

I'm tempted to attack cleaning all connectors (from/to) the abs module, has anyone can point to where i can fins some schematics.

deilenberger

How long have you owned it?

As far as schematics - the schematics are many pages long. I'd suggest looking at a subscription to AllDataDIY - it's very reasonably priced - and the info on it comes out of the factory service manual. I would guess they have schematics for the 957 series (they do for the 958 series.)

Resistance checks on the sensors might be a good first step. And the most likely place for there to be a failure might be the connector from the wiring harness to the ABS sensor wiring. That's exposed to weather..

The reason I asked how long you've owned it is - I sort of doubt unless the car has spent it's whole life in a desert - that it never had a footwell flood. It seems every Cayenne has one sooner or later. The damage to the wiring isn't obvious usually until you start unwrapping the harness running through the footwell. So I wouldn't altogether discount this as a possible failure point.

All the communications errors are what make me look in that direction. That's rather common when the wiring in that harness starts acting up.