Trunk and doors all unlock on their own

[Retiredandhappy]

Hello all,

I have searched wide and low for anyone with a similar problem to no avail.

Recently, I have come back to my vehicle after parking outside overnight (hotel and nephew's driveway) to find the trunk popped open and the doors unlocked.  I have a '06 C4 and have tested both key fobs for unlocking the trunk.  If the vehicle is locked and I open the trunk with the keys, all unlock, but the doors will relock automatically after about 30 seconds as I have observed previously.  Never have I unlocked the trunk and not had the doors relock if I did not open a door withing 30 seconds.  I have tested the trunk release switch on the door sill by locking the vehicle with the driver's window lowered then reaching in to try unlocking the trunk.  It will not unlock from inside the vehicle when the alarm is set, the release latch does nothing.  I am stumped as what would cause everything to unlock and stay that way without any action on my part to open a door before the 30 second timeout.

 

I have obtained the following trouble codes with my Durametric:

P1163: Oil Pressure Switch

8035: Left seat heater

8036: Right seat heater

C152: Comm PSM control unit

C158: Comm gateway control unit (CAN drive)

8014: POSIP LIN no communication

8007: Gateway incorrect coding

8042: Front luggage compartment unlocking

C102: CAN single-wire operation "comfort".

 

I have not cleared any codes yet as I may need to run this to a shop with more background experience than I.  I am concerned with the number of codes pointing to CAN communication errors.

 

Any thoughts from the greater masses out there would be much appreciated!

Gary

[wizard]

Have you checked that your battery is good ?

[Retiredandhappy]

Yes, batteries are OK.

Mystery resolved.  Found this link on 6Speedonline and it described my symptoms to a T.  http://www.6speedonline.com/forums/997/260646-frunk-hatch-open-their-own-randomly-3.html

Turns out that most likely cause of trunk opening is key in pocket of jeans activating the trunk open button.  If the trunk is opened and not closed, the doors will remain unlocked.  If the trunk is then closed and the doors are not opened, they will relock in about 15 seconds.  This is also covered in the manual...... RTFM!!!!

[Richard Hamilton]

You can buy a set of replacement buttons for the Gen1 keys which makes them less prone to accidental operation.  They aren't cheap, but are effective.  Another option is to buy a used Gen2 key head case and swap the internals.  There are also aftermarket Gen2 key head cases available.

[Retiredandhappy]

Thanks Richard.  I have seen notes on improved key cases and also on a home remedy to trim the nub on the inside of the trunk open button.  Will try that first as this is no cost.   Cheers, Gary