Weird central locking problem...

[Eddy Matthews]

My 2007 2.0i Z4 has developed a bit of a weird central locking fault.... Press the key and everything locks as it should, first time every time, But occassionally the 2 doors will unlock themselves at random - The boot and fuel flap are still locked. The car can be parked for days and the doors stay locked, then at other times they unlock themselves at random time intervals... There doesn't seem to be any definite pattern to it!

As I said everything locks and unlocks from the remote perfectly, but it's got to the stage that I never know if I will come back to find the car locked or unlocked!

Has anyone any ideas what would cause this?

Regards
Eddy

 

[Ewazix]

I've not heard of this self-unlocking symptom on a Z4 (except for sofa-bumming the keys in a pocket?) but had the same on a Merc SLK and it turned out to be the central locking module waking up and cycling every few minutes. The E85/6 Z4 has a very common fault with the 'GM5' module which controls the central locking and causes other random locking/unlocking issues, that's where I'd be looking after checking the battery is OK as they cause random electrical faults. I've swapped out a couple, here's a link, it's basically the same on pre-facelift and facelift models and isn't too difficult or expensive if you DIY it.

https://z4-forum.com/forum/viewtopic.php?f=34&t=102586&hilit

 

[Ducklakeview]

As above, GM5 module is the usual suspect. Get the codes read first though before ding anything else, it could be a shorted wire.

Mike