Central locking problem

[Siddy1200]

I have a 2004 E53 3.0i, it's low km and it pretty good condition. Had it a while without any issues.

Recently, the rear doors won't unlock with the central locking.
Also the lower tailgate won't unlock either.

The front doors and upper tailgate are still working fine

When I press the unlock fob button 1 time, the drivers door unlocks (as normal).
Then the 2nd press unlocks the front passenger door and also allows the upper tailgate to be opened.
But the rear doors and lower tail gate are all still locked.

I can still open the rear doors by pulling on the inside handle.

I had a similar issues with my E46, it turned out to be a common problem with the gm5 module, I replaced a relay and it was fixed. I see the E53 doesn't have a gm5 but a similar module might be the problem. There is a relay that does both rear doors but it's a seperate circuit that does the tailgate so I am confused as to what could cause this problem.

From doing a search, I see the most common problem is with the door actuators but I don't think this is my problem.

I have checked the 3 fuses that are labelled central locking.
I have disconnected the fuses for 5mins to reset the system.

Any ideas?

[oldskewel]

You may have seen my fairly recent report where a bad driver's door lock actuator caused many problems with central locking.

One main conclusion from that is that the system is amazingly connected and complicated, and the root cause could be somewhere in the chain that you are not suspecting.

The other main conclusion was that while one approach to the problem is to carefully document symptoms (as you've done carefully here), due to conclusion #1 ^^^, interactive OBDII based diagnostics might be really helpful. I used both INPA and Foxwell. They gave useful, but different (!) information. The Foxwell in particular ended up being the thing that guided me to the answer, which in my case was the DLA.

So I would get some advanced (not just a generic code reader) OBDII diagnostic tools going on this one.

[Clavurion]

The only common factor is the body module. For rear door locking GM3 has internal relays like GM5 or some newer versions solid state FETs.

https://www.bmwgm5.com/GM3_Info.htm

Regarding only drivers door unlocking with first press of remote and rest of the doors with second press is a coding option called selective locking.

[Siddy1200]

Originally Posted by oldskewel

You may have seen my fairly recent report where a bad driver's door lock actuator caused many problems with central locking.

Yes I saw your post, I was planning on following your guide but then i realised that only the front doors have those actuators, the rear doors are controlled by the gm3 module.

I understand what your are saying, it's an over complicated system so maybe it is related to the front actuators.

This seems like a a rare failure. I think I will have to take the rear door cards off and start probing at wires. Problem is, it's an intermittent problem that just started last week and has gone now.

I'll let you guys know if I figure it out.

[oldskewel]

Originally Posted by Siddy1200

Yes I saw your post, I was planning on following your guide but then i realised that only the front doors have those actuators, the rear doors are controlled by the gm3 module.

I understand what your are saying, it's an over complicated system so maybe it is related to the front actuators.

This seems like a a rare failure. I think I will have to take the rear door cards off and start probing at wires. Problem is, it's an intermittent problem that just started last week and has gone now.

I'll let you guys know if I figure it out.

In case it helps, here's one specific test I did:

(and the answer ended up being the driver's DLA, which fixed everything)

With the foxwell running in active testing mode, I was going through the door lock actuators, commanding unlock, lock, and double lock. Some doors had failures, some had flakiness. On the rears, I think at one point they worked, and then they failed a dozen times or so in a row, when commanded to lock, there was a clunking noise and the locking button (that sticks up) would move and end up about half way down.

And this was all done with a battery charger hooked up to the jump ports in the engine bay, so there was no lack of system voltage that may have caused flakiness due to weakness.

So one way or another, not sure why or how, not willing to figure it out ... a problem with my driver's DLA caused definite repeatable problems with the rear door lock actuator control.

No ideas about your problem other than what I'm reporting on my own situation.

And unfortunately, general advice for an intermittent problem is that troubleshooting can be futile while the problem is not present. Sometimes the best/only thing is to prepare for troubleshooting and then wait for the problem to reappear.

[Siddy1200]

Originally Posted by oldskewel

In case it helps, here's one specific test I did:

(and the answer ended up being the driver's DLA, which fixed everything)

With the foxwell running in active testing mode,

Would I be able to do that without Foxwell? I have heard of laptop software that's used with a cable (inpa?) Would one of those software based systems work to test central locking?

[Clavurion]

If you want to rule out driver's door module simply remove it from the door card and disconnect it.

[oldskewel]

Originally Posted by Siddy1200

Would I be able to do that without Foxwell? I have heard of laptop software that's used with a cable (inpa?) Would one of those software based systems work to test central locking?

I doubt it on the INPA. I used that as well - the PA Soft 1.4.0 BMW Scanner clone thing. Interestingly, it was almost like I was working on two different cars while I was using those two things (INPA and Foxwell). The "real" problems were basically the same on both, but both also had their own doubtful faults reported.

Regarding Clavurion's suggestion to remove the DLA from the equation here ... considering all the other things that make this a tough problem, that's easy to do. I'd do it. Just take off the inside door panel, peel back the foam door liner and you'll have easy access to the connector to the DLA. Can unplug it without removing the DLA.

Also, repeating myself, I'm not saying I think your problem is the DLA because it was for me. I'm saying that the whole system is very complex, and the symptoms of a problem may be far removed from the root cause ... as it was for me.

If I did not have the foxwell and the INPA, I very well may have concluded that all my DLAs were bad, tried repairing or replacing, possibly causing more problems, etc.

[timmyc]

I would follow oldskewel's advice and try to connect a known 'good' master switch. I had all sorts of issues with locks and mirrors. Turned out to be the master switch.

Good luck!

[Siddy1200]

Thanks guys I will try disconnecting the drivers DLA next time it happens.