Warning light --> "tail gate Error: 0x003D: Central locking system: Short circuit or Open circuit at Motor T

[matthijsfh]

Good morning,

Hunting down another error light this time. Yellow "light" symbol on the dashboard --> Inpa --> error 3D/01 "tail gate short"
Tail gate does not operate properly on first try with the remote key, it opens and immediately I hear it lock again. 2nd try always works fine.

Error registration 2 : 0x003D: Central locking system: Short circuit or Open circuit at Motor Tailgate <<<<!!!

* Is it really the tail gate motor?
--> I saw 1 comment on google that is might be a rusty/corroded licence plate light bulb.

Anyone any experience with this error code?

 

[enuff_zed]

Not one I've come across, but if there is a bulb out warning on the dash and you can't see a bulb out, then I'd definitely be checking those licence plate bulbs.
Can't see any reason at all that a faulty lock would show as a bulb out.

 

[matthijsfh]

Hai,

It seems that all "shorts, bulbs, electrical mishaps" are reported using that single bulb light on the dash. But the error code points towards the lock.

Looking at the wiring diagram, it seems very weird that tail gate light bulb is related. Will check though.

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Update: key on --> warning light appears --> open tailgate a few times with buttons --> light off.
Just ordered a new lock. Maybe my lock got corroded or something's wrong with it causing it to short or the micro switch to behave incorrectly.

===================

Greetings Matthijs

 

[Usel]

All the locks on the Z4 are only wired to the GM5. The GM5 has two wires going to every lock separately on the car, drivers door, passenger door, centre storage flap, fuel flap and the boot.

To lock and unlock, the GM5, just reverses the polarity of those two wires.

You can test the boot lock by disconnecting the socket and connecting two wires to it and then just touch them onto a 12v battery. It only takes a split second of 12v to flick the lock. Reverse polarity to flick the lock the other way.

 

[matthijsfh]

Hai Usel,

All the locks on the Z4 are only wired to the GM5. The GM5 has two wires going to every lock separately on the car, drivers door, passenger door, centre storage flap, fuel flap and the boot.

Thank you for the quick reply. Indeed, you are right, except for the trunk lid. That one seems to be controlled with 1 wire. And seems to have a feedback contact to indicate to the controller the lock is open.

X13004 is the central mass connection in the right side of the trunk (I just found out ;-))

 

[Usel]

Hai Usel,

All the locks on the Z4 are only wired to the GM5. The GM5 has two wires going to every lock separately on the car, drivers door, passenger door, centre storage flap, fuel flap and the boot.

Thank you for the quick reply. Indeed, you are right, except for the trunk lid. That one seems to be controlled with 1 wire. And seems to have a feedback contact to indicate to the controller the lock is open.

X13004 is the central mass connection in the right side of the trunk (I just found out ;-))
image_2025-01-27_115737856.png

Ah yes of course, the boot lock is the only one to only need unlocking :rofl:

So only 1 wire needed to unlock it

Every day's a school day

 

[matthijsfh]

So my current guess:

Feedback contact in trunk lock is shorting --> when I activate the lock, immediately the contact responds "yes I am open" and the lock is disengaged before it has actually opened.

Just bought a new lock. Lets see what that does.

 

[enuff_zed]

So my current guess:

Feedback contact in trunk lock is shorting --> when I activate the lock, immediately the contact responds "yes I am open" and the lock is disengaged before it has actually opened.

Just bought a new lock. Lets see what that does.

Well, if it's not that, then I had a similar issue with a left door lock. It would open then immediately close, sounded like a machine gun for a few seconds until the GM5 stopped sending the signal to it. In this case it turned out to be a fault in the GM5.

 

[matthijsfh]

Update

Replaced the trunk lock. Works rock solid now. Seems to have fixed the issue. Was planning to check the feedback contacts but ran out of time and forgot.

Greetings Matthijs