I get the following on my Cayenne 2004 S

every morning, when I start my car, my PSM failure light is fine. However, after an average of 15 minutes driving, and it always happens when car is idle or in traffic, car/engine shuts down. When I turn the car back on, the PSM failure light shows up. Car never shuts down when PSM failure light is on. When the PSM light is on the engine is performing badly.

Any help appriciated

 

Find out what the fault codes are, if not you will have to take it to the dealer and they will tell you.

 

There are many different fault codes most of them are DME related saying that DME is faulty but if you turn off the engine and clear the codes everything is working again until what I described in my post happens.

 

Hi,
I am having all exact symptoms as you have on my 04 cayenne-s. Any update? Any help will be great appreciated!

Thanks,

 

I had to replace the main control unit, i think it is called DME, cost about 2000 euros
Good luck

 

I saw this display once while troubleshooting a surging problem on my 04 CS . I fitted some new "Bosch"MAF Sensors (which turned out to be fakes, I eventually got the right ones though), anyway I had to temporarily disconnect the MAF sensors to get the car started . With the MAF sensors disconnected, the car will start up but may idle badly, and you will get the PSM Failure display.
So long story short, maybe check the plugs on your MAF sensors are not loose, or maybe you have a faulty MAF sensor.

 

Thanks for the help! Guess I need to replace the DME as well; but only authorized Porsche dealer can code and adapt a new DME and they are talking about couple thousand dollars job too. No wonder this car is depreciate so much year and year!

 

I can get you lined up with a ecu for a few hundred. If interested PM me.

 

Finally have replaced a new DME; but after running for 15-20min still same issue ! Thus it is not the DME . Will try the crankshaft speed sensor the next.

Any input will be great appreciated !

 

Before you replace anything else... you need to obtain a Durametric or take it to someone with a PIWIS and read out the codes that show up. Then we can talk about next steps...

 

There is a P0035 crankshaft position sensor "A" code stored in the DME; are there 2 crankshaft sensors A & B? I believe there is only one crank position speed sensor. Also there is a "DME" error stored in the tiptronic.

Thanks,

 

It looks like you may be using a standard OBDII code reader, which gives universal P-4 digit codes. The problem here is that your standard OBDII reader is only made to read out emissions related codes. It will not read out all codes in your CANBUS computer modules. So you are trying to diagnose the issue without looking at the full picture. Do you have a Porsche Independent Mechanic that can read out all faults in all modules? Just trying to give you the best advice from what I see..

FWIW, a bad crankcase sensor and/or bad cam sensor can definitely stop a car without any warning.

 

Thank you much for the info, I have a "Launch" also "Val-com" doing for diagnostic. Kind of challenge task this time; will keep you posted!

 

Cool! I haven't heard of "Launch", but I think you mean "VAG COM", right? I know that is for Audi/VW guys... not sure if it is plug and play with Porsche. However, from what I understand, the Durametric program is based off of VAG COM for Porsche.

 

I just thought I'd add something to this thread after my recent experience. I also experienced an intermittent "PSM Failure Workshop" warning on my 04 CS.


At first it would occur only on start up, not from a cold start I should add, usually when starting from an intermediate temperature, like for example after driving to the supermarket and leaving her parking for an hour or so. No problem when starting from cold or when fully warmed up. I'm not sure of the significance of this, but it's just the way it was. The engine would turn over for longer then usual before starting and I would get the "PSM Failure Workshop" warning. If I drove with the warning on, performance was notably poor (misfiring). The warning would go away immediately if I switched off and started again.
The problem later escalated (after a few months) to stalling at idle and eventually to stalling even while cruising (but then recovering).

Anyway drawing fault codes gave the following codes



I replaced the crankshaft position sensor to solve the problem.

It's actually quite an easy job, most difficult part was to get it unplugged !