kelticcare

I'll start from the beginning so not to miss something I've done, so some of this info may be irrelevant. 05 Cayenne Turbo

Fitted towbar and electrics, and now warnings all over dash for PCM and Air suspension. So...

1. Lifted car to terrain height, took off rear bumper, rear lights and left car overnight.
2. must have left something on, battery dead. Put on charger in engine bay points and only reading 5v, would not charge as result.
3. Removed battery from under seat, tried again and reading 12.5 volts, took charge ok, so installed back
4. Started car, and now
a) air suspension fault (changed gaskets 6 months ago) - although car going up and down fine - it was left up overnight though, with a flat battery.
b) PSM fault. Car will not clear PSM fault as per owners manual, and PSM on/off light on dash not working.
c) Clock resets itself after I start the car back to whatever time it was last set ie, manually set clock to 10.05 am, it will then work while running or sitting until car is restarted later when it will jump back from current time to 10.05 am?
5. looked for auxiliary battery under BOSE sub in boot - i don't have one!
6. Bought a new battery anyway, changed it over and still no difference.
Nearest Porsche 2 hours away!
Any one got any ideas?

ferraristyle

Just a suggestion, take the car for a drive of a couple miles. When I installed my new steering wheel I disconnected my battery. When I turned the car on I had a suspension, lights, and psm code. Off and on with the battery again as well as letting the car sit, start and restart and still codes. Took the car for a light drive, maybe 3 or 4 miles, came back, shut the far off, weighted 5 minutesmwith key out, started it up and codes were cleared.

User 4221

Don't panic. These cars behave very erratically when a battery goes flat and is replaced.

I suggest going through several cycles of: door unlock-start-drive-door lock. This typically resets the electronics and brings things back to normal.

I had similar issues the last time I replaced my battery. After a few reset cycles, all was OK.

Good luck.

mudman2

You have to turn on the tow electrics with PIWIS or the suspension will get itself all farkled. The computer has to be specifically told the tow is present its not plug 'n play in any respect.

Sounds like a number of control units especially Comfort CU need to be reset, again with PIWIS

Sounds like a drive for you to Dealer or an indy with PIWIS