Haunted Cayenne; CRAZY Electrical Malfunctions

[RNajarian]

I was getting my garage queen 955 ready for a family trip. After nearly 9 years the car has only 40,210 miles.

When I started the car, the LED dash display remained black, the car flashed 4 wheel drive error, it also flashed a Porsche Stability Management error, then the side view mirrors retracted, then deployed several times. The PCM dimmed in and out. I had previously driven the car a month ago and at that time everything was working normally.

Immediately, I thought, "Oh $h!+ this is going to be an expensive pain the the a$$!"

However, I remembered my wife's Mercedes had simular electrical gremlins when her battery was going bad. So I hooked up the car to a battery charger, and 1/2 hour later it started up with no problems.

Diagnosis: The original battery installed in 2004 (Model Year 2005) was probably bad.

Treatment: Three hours later, new battery was installed. (It was a complete Pain in the butt!) Car Started up normally, no gremlins.

I suggest anyone who wishes to replace their own battery, get the 16 point allen wrench to remove the bolts, otherwise you will strip the bolts. Also be careful removing the seat trim at the base of the driver seat. If you are not careful you will break one of the connecting tabs, and need to epoxy the broken tab back on.

Hope this helps someone

Regards

[914-6Porsche]

I have 2004 T and it needed a new battery after 5 years. You probably needed a new one anyway. There is a constant drain on the battery because of all of the Star Trek things in the beast and after a month the battery could use a charge anyway. I would personally not let one sit for more than 2 weeks without good drive or an overnight trickle charge, I do a trickle through the cigarette lighter socket. Good Luck

____________________
2004 Cayenne T
2006 Cayenne S Titanium
1970 914-6 Original Owner #397

[Nostril Cheese]

Yep, a failing battery will cause all sorts of gremlins and the PSM error.

[RNajarian]

Well after 8 years (and only 20,000 more miles on the odometer) it was time for another battery.

Picked up an AGM for $1 less than the regular lead acid I bought in 2013.

Currently I have the PSM error because the steering wheel sensor needs to be recalibrated. I’ll do that tomorrow, but if anyone wants to know how to reset it after a battery change here are the instructions from the owners manual.




Regarding PSM failure, here is how to clear it (from the operator's manual):

----
Putting vehicle into operation

After the battery is connected or after an completely discharged battery is charged, the mul-tifunctional PSM light lights up on the instrument panel and a message appears on the on-board computer to indicate a fault.

This fault can be remedied with a few simple steps:

1. Start the engine.

2. With the vehicle stationary, perform a few steering movements to the left and right and then drive a short distance in a straight line until the multifunctinal PSM light goes out and the message on the on-board computer disappears.

3. If the warnings do not disappear, then: Drive carefully to the nearest authorized Porsche dealer. Have the fault remedied.

4. After the warnings disappear: Stop the vehicle in a suitable place.

[RNajarian]

Well it looks like I only got 4 years 6 months out of my latest battery . . .

I went to move the car after it had been sitting for 6 weeks and it was dead.

This thread is helpful to help me keep track of when I change batteries.

[RNajarian]

Believe it or not after 20 years of owning my car, I have some new insights to share with the group.

The first two batteries I had I was able to get eight years out of them. My third battery I could only get four years out of. The reason for that is my third battery I bought a Smaller battery which fit inside the battery tray easier but it only had 800 cranking amps.

As a result, this was a much cheaper battery. The one I bought today was an AGM battery with 950 cold cranking amps which cost $260

One bit of advice for anybody who’s replacing your battery and using a larger battery like the one I bought today. Fit the battery cables on First before securing it down with the two ties to the battery tray. The reason is is I secured the battery first and realize the positive cable lead would not reach the terminal . . . But once I removed the tiedowns, I was able to put the cable on and slide the battery into place.

The Pelican write up is spot on as always, and if you’re interested in my advice, I would be to get the higher cranking battery because from what my experience is, they seem to last twice as long. I hope in eight years my son who will then be 22 will read this and know what to do while I’m hopefully sipping a cold one in the backyard.