05 CTT stuck in 2nd gear.. among other things

[Patrick Manning]

Hey everyone, bare with me whilst I get through this and hopefull someone has some suggestions or can point me in the right direction.

Since I bought my 2005 Cayenne Turbo, the PSM and ABS lights come on intermittently. They tend to go off after the car is turned off then on again. Dealer said it was the right rear wheel speed sensor but no point in replacing it until the brakes are done.

A couple of days ago by battery died, which is weird because the dealer I bought it from said they had recently replaced it. I went in the mall for about 30 mins and left the key in the ignition for a passenger. The radio switched off to protect the battery after about 10 mins, yet when I came out the lights here still on and the battery dead, is this normal?

The next day the PSM and ABS lights came on as well as the check engine light but they have not gone out in 2 days. Since then, I have to keep the transmission in manual shift mode as in regular Auto mode, it will not shift out of 2nd gear. On top of that, if I manual shift it up to 3rd, 4th etc... and then pop it into Auto mode it automatically shifts back to 2nd gear and won't change. Any help with this is much appreciated.

Another issue that has come up in the '4 wheel drive system faulty' message and light come on intermittently as well. When it comes on, the switch to lock the diff does not work, when the light is not on, the switch works fine... is any of this stuff inter related?

[deilenberger]

When a battery goes dead on a modern computer controlled car - all sorts of oddball things start happening. My WAG - you're due for a new battery (despite the claim it was replaced..) Either it's bad or your charging system isn't up to snuff. Different parts of the vehicle will start throwing codes as their computers go into a safety mode to keep from melting down due to low voltage.

Got a voltmeter? What is the standing voltage on the battery (car off for an hour or so..) and then the voltage with the engine running and nothing on?

I'd expect to see 12.8V+ (#1) for standing voltage and 13.4-14V (#2) for idle charge voltage with nothing on. If #1 is low - your battery has a problem. If #2 is low, you may have a charging problem.

[wvicary]

Is your vehicle equipped with two batteries?