Deadlocked Door Advice

[nial]

Hello,

A good friend has a 2007 A3, 5dr which has a problem with the door locks. Essentially, the two offside doors locked one day and now won't open, either with the fob or or via the key, nor can they be opened from the inside or outside with the handle. They are deadlocked I assume. VCDS has logged two faults and says something like "No comms with drivers door" and "No comms with rear right door".

So, in order to help him out what are my options? I have read that cutting away the rear striker plate is an option by removing the plastic trim on the b-pillar and using a dremel to cut the captive bolts for the striker plate. Is this practical.

Perhaps it is possible to remove the door panel in-situ with the door deadlocked? Is this an option? i understand that the fuses for the CCM are in the drivers door jamb?

Any help appreciated!

[nial]

Just an update:

I managed to get the door card off in one piece with only a little minor damage. I can see the door outstation and I have probed it for power but it is completely dead - I believe the heavy red/grn is a B+ supply and the brown is GND, but there is no continuity from this to chassis GND which leads me to believe that the connector at the A-pillar may be faulty, but it would be odd for both o/s doors to suffer in the same way.

My original thinking was that if I could power the door outstation separately, then assuming all of the other wiring was intact (CAN_H and CAN_L in particular), then it should be possible to get the outstation to 'talk' to the CCM and release the deadlock. This now seems less likely.

So, further to my earlier message: does anybody know of a way to either manually release the deadlocks or indeed where the CCM is on these cars - I hear conflicting messages: some say the boot but others say under the steering column.

Again, any help appreciated.

[Crasher]

Have you tried diagnostics? Have you disconnected the battery for a while.

[nial]

Have you tried diagnostics? Have you disconnected the battery for a while.

Thanks for the response.

Yes, battery disconnected for a few hours but no difference.

From my first post: "VCDS has logged two faults and says something like "No comms with drivers door" and "No comms with rear right door". I would expect that even if the CCM got a little "confused", the door outstations should still have B+ and GND?

Sent from my SM-N950F using Tapatalk

[nial]

Reading through the SSP(312) on the 8P electrical system (specifically the "Door control units J386 and J387" section), the text says:

"Emergency function 2
If the CAN link with the driver's door is
interrupted, the vehicle can only be locked
manually by way of the lock cylinder.
The lock/unlock button does not function."

This seems to indicate that the door lock should continue to work with the key manually via the barrel should there be a comms failure, *however* if you do not have a B+ supply then I assume that the locks cannot work manually as normal.

So my question (for anybody who might know). Where is the B+ supply for the door outstation (J386) derived from on the 8P, is it J519 or is it a terminal 15/30/etc. via a fused supply ? It might help if I had a diagram I suppose, but I am working in the dark on this one :-)

[nial]

For those interested, it turns out the the wiring harness in the drivers door jamb was the problem but there was no way to get at it in order to get the door open.

The solution I came up with was to hardwire B+ and GND to J386 door outstation on pins 19 and 20. Once I had done that I expected to be able to open the door using the key in the lock but this was not to be as somebody has previously 'fixed the mechanical lock barrel mechanism linkage until it was broken'

So, I then thought a little further about things. With the door module powered-up via my hardwired supply. I had a look at VCDS to see if it would talk to J386. No luck unfortunately. However, I twisted a pair of wires and connected CAN_H and CAN_L of the door module to the CCM databus directly to the door outstation. The CCM could now talk to J386 and I was able to unlock the drivers door via the fob!

Once open, I was able to look at the door bellows and connector in the jamb where once the rubber boot was pulled back, a healthy growth of green corrosion on the two parts of the door connector and several physically broken wires in the bellows itself were revealed.

All-in-all not too-bad to sort out once one has the required wiring info for the door/outstation/CCM. Getting the door card off was probably the hardest bit.