Electrical problem puzzlers

[mdhhorn 1]

Hello everyone!  I’ve run into some electrical problems on my '08 Turbo and I’m stumped....  I've looked through a lot of Renntech posts and don't see any thing close. 

• First the panoramic roof and sunshade were opening and stopped about foot open.  Maybe coincidence, it happened right when someone opened the door.  I’ve checked practically every fuse even pulling the pano-roof control unit (back where the motors are located, and the circuit board looks okay.
• Then the instrument panel has started to act strange.  The gear indicator shows that it is all gears at once, see the photo which is while it is in drive and moving.  I can shut the car down and restart and the problem goes away.  The time keeps changing randomly and the outside temperature is wrong.
• The button that opens the rear hatch that’s on the driver door has stopped working.
• Then my battery died, it was five years old so no surprise.  After I replaced it the airbag indicator on the panel has lit up. 

I’ve tried to reset the instrument panel (Main Menu> Settings > Factory Reset) but it will not allow me to select “Reset”.  I’ve also pulled the fuse several times to reset the panel but no change.

Today, I’ve connected my iCarSoft POR II diagnostic tool to the car. 

• The Airbag section says it “cannot connect to the ECU” so I can not reset the airbag light.  There are YouTube videos of people using the tool on Cayenne’s (albeit on newer models) to reset it so I believe I can.
• The Panoramic roof says it does not have any DTC codes. 
• The lift gate button on the driver door indicates it has appropriate voltage and no DTC codes.
• Also, no DTC codes for instrument panel, electrical system or DME

I’m not sure this is related or not, I changed out the interior incandescent bulbs with LEDs.   I now know that LED bulbs give off electromagnetic interference but seems remote.  (as a side note, I found this out when I put LED bulbs on my garage door opener unit and it stopped receiving commands from the remotes – I had to get special bulbs from Amazon)  Yesterday, I removed all the LEDs and went back to the old bulbs – no change.

Any ideas, suggestions or guesses?

Thanks,

Mike

 

FYI: The car is in Drive, "D"  and is in motion. 

Edited October 3, 2019 by mdhhorn
add photo

[Loren 2,322]

These cars (specifically Cayenne)  seem very sensitive to weak a battery and poor grounds.

Whenever I see multiple electrical issues on a Cayenne - that is where I start.

[mdhhorn 1]

If I have changed out the battery, how do I reset the electrical system?

Thanks.

[Loren 2,322]

You should not have to - unless you hooked up the new battery backwards.

If the polarity was hooked up correctly then you need to start looking for poor grounds. Starting with the battery cable then chassis grounds.

[mdhhorn 1]

Update

I updated the firmware on my iCarsoft and reran code check. Now I’m getting the following code on the panoramic:

— 0470 CAN comfort in single wire operation

 

also I’m getting the following error on the Gateway:

— 1336 CAN comfort OFF

would this info help in my search for the grounding problem?

 

[mdhhorn 1]

Loren- i’m still having the same problem, does the codes above about the CAN comfort help? I did pull up the carpet under the driver and passenger areas and looked at the all of the wire bundles. Under the driver seat I had a couple corroded wires but after fixing them it did not help.  

Edited July 9, 2020 by mdhhorn

[GSpence2 16]

I’ve had the same issue and Loren was right - bad grounds all over the place and a battery with a couple of weak cells. I replaced the battery cleaned and redressed the grounds and 99% of my issues went away. 

[mdhhorn 1]

Thanks for the post!  Did you have a wiring schematic or did you just start pulling up the carpet and search for the grounds?

[GSpence2 16]

Good old pull up and search and you’ll need to check the grounds on the chassis rails up front and rear floor too under the rear seat and spare tire

[GSpence2 16]

My main issues were under the seat at the  battery box in the engine compartment at the front the frame rails at the front and in the rear corners where water has collected. The connections were all dirty cruddy and corroded. 

[mdhhorn 1]

Thanks GSpence,  sounds like a fun weekend project -- well worth it if it fixes my pano roof.

[mdhhorn 1]

I pulled up the carpets.  Under the driver carpet I could see salt water deposits from the winter.  There was a thick black line running from  Terminal 15 that had a very corroded spice to three other large black lines.  I ended up replacing about 2.5 feet of wire as the wire inside had turned black, I finally found shinny copper just under the dash.  I then reset the car electrical -- removed the battery cables, connected them for 15 minutes they left them unconnected for 15 minutes.  Next I reset the panoramic limits (turned it to the A position and tilted the dial for five seconds then held it for ~20sec until it ran through the reset). Now my panoramic roof works!!  first time in over a year.   I will now see if it fixed the other intermittent electrical problems I have.  Thanks everyone for their input!!!!!!