Electrical malfunction help ASAP!

[eurogreek1]

Was driving the X last week and the cars electrical system went crazy. Lights started flashing everywhere. Transmission malfunction, abs lights etc. I lost all power to the car basically. The car ran fine but was scared to drive it in case of damage. Had it towed to the dealer and they said let's start with your battery. I had an after market battery installed by batteries plus last year with no problems. After the new battery instal, dealer said that my faults won't close and it might be due to a subwoofer I had installed 5 years ago. I took it to car toys and they said its impossible because they only spliced into the stereo wire only.

Make a long story short, my transmission malfunction light keeps turning on through the nav screen and constantly stays on by my speedometer. The rpms and speedometer still idle out of control while I drive. The weird part is that there no error messages when I check the nav screen.

Dealer wants me to go remove my stereo system and charge me to rewire the stereo wires that were spliced into. Cost is around $800 on top of $550 for the new battery.

One thing I want to point out if it has an correlation. I was in a automatic car wash last Monday and during the high pressure rinse on the front end, I noticed the cars rpms go up. A few seconds later the transmission malfunction light turned on then turned off. Didn't think nothing of it because it went away and the car drove fine. Weird part is it still drives fine.

I also took it to a transmission shop and they said it all electrical.

Any help would really be appreciated.

Please email me for my number if someone wants to talk.
[email protected]

[TinyRK]

Aren't the wire rubber seals of the trunk door prone to water damage?
I recall that there were some issues reported.

[eurogreek1]

I have never noticed. I currently have the X at a local bmw shop. So far he has 3 hours into it. Let's see what he finds.

[seattle]

Interesting point about high pressure car wash. If you look at the wheel assembly, you will notice there's bunch of sensors with wires. Could a water jet knocket something off, or at least got water in it?

[eurogreek1]

So my local repair shop said that they basically took the car apart to check all faults. They ended up pinpointing all the faults to the rear PDC harness in the back bumper. They said there 90% sure that's the cause. Should know today because they had to go to the dealer for the part. I want to know if it had to do with any water.

The car wash I went through also had high pressure undercarriage wash while entering.

[ard]

^^ Be interested to know what kind of car you have...

Why a new battery last year? History of high discharge issues causing the batteries to fail? Interested to hear what precisely in the PDC harness caused this and how.

[eurogreek1]

I have a 2007 4.8.

Changed the battery last year because my car died.

They told my they ran all the electrical faults and started troubleshooting them all. Somehow, they came to the pdc harness and unplugged it. Drove it for about 15-20 miles and now faults at all.

So here's the new story. Here's were it gets interesting. After giving the X a final car wash and taking it on a final test drive, the transmission malfunction light turned on! They didn't know what happened. They think water obviously has something to do with it.

They basically took the car apart. Front and rear seats, carpet, etc.

I know the tech is good. He always serviced my cars when he worked at bmw for 20 years. He also mentioned that the 07 X5 has electrical problems.

Any help so I could pass this along would be appreciated.

Starting to think I should trade in the X. Sad part is it only has 66k miles.

[TerminatorX5]

You said it had power undercarriage wash, and when the rinse was at the front, your RPMs surged and the tranny light came on...

it is clear that the rear seats have nothing to do with this, nor the rear PDC...

you should check for loose connectors in the ABS module, in the speed sensors around the front wheel hubs - the water jets may have dislodged the wiring, and when the module is not receceiving the proper signal/information, it will cripple the system, in order to protect it...

lift the car, and visually trace the trajectory of the water jets entering undercarriage and see if there are any wires in the path - the undercarriage should be protected by a shield pan on the bottom, but i have seen many bimmers missing that cover in action...

[eurogreek1]

He checked the abs module and said it was fine. Not sure about the speed sensor etc.

Thank you

[eurogreek1]

Any suggestions would be great. My tech looked at everything mentioned and still no corrections. Transmission malfunction light always is consistent.