Jacob Hallenbeck

Hi everyone, was hoping to get some insight into where to look for my electrical gremlins. I will start with: I have already done passenger and Driver side floor wiring repairs. So unless it directly sounds like i need to go back again (i have checked the repair for new corrosion and its clean) I'm gonna leave it be.

To start the car is a 2004 Cayenne S and it had a new battrey put in, read 12.3 volts with key off.
Durametric fault codes are as follows:
Tiptronic Transmission:
1626 Battery voltage term 30 Short circuit to ground

Instrument Cluster:
470 Can comfort in single wire - open circuit
459 PCM2 - no signal (I have an aftermarket radio? The car also came with a started base looking radio?)

Airbag:
1222 pass front airbag fault *
1218 pass side airbag value exceeded *

Air Conditioning:
1592 Air quality sensor open/short to B+
1299 Gateway Implausable

Vehicle electrical system:
907 Load managment Operat. on vehicle electrical sys./DME control module
1299 gateway

Steering wheel:
1747 Heated steering wheel sensor open / short B+
1426 Control unit in steering wheel no signal / communication

Gateway K/line:
461 Pass memory seat fault
470 Can comfort in single wire operation Open circuit
459 pcm2 no signal / communication

I just fixed the passenger side wiring before clearing and reading for codes, For all intents an purposes my car doesn't have a passenger seat nor any modules attached to it, (probable cause i know, im looking for one) The instrument cluster voltage reading is a half volt below battery voltmeter reading and the key also gets locked in the cylinder sometimes, starter is weak / have to run key more than once for it to crank over, cannot shift trans with wheel or shifter, Nothing on wheel works including horn. I'm sure a lot of these are semi or totally unrelated. But im curious if anyone has seen something similar that ends up being some random thing here or there. For me im mostly only worried about the can system and the open / short circuit faults. As a note, none of these codes are populating a code on the dash besides the air bag light being on.

I know im tossing this out before doing the most obvious fix, but until i find a good black seat this is as far as my diag skills have taken me.