Hey Chap(ette)s!

Lastest issue that I'm hoping some of you kind people might be able to help with: The central locking has stopped working on both rear doors. I recall them both working about a month ago, and now neither do. They appear to have deadlocked themselves too, since they can't be opened from the inside or outside at all.

I have tried 'banging' as hard as I dare whilst repeatedly locking and unlocking on the fob and with the key in the driver's door, but no luck.

If I listen at the doors whilst locking and unlocking on the fob, I can hear something trying to move, but there's no definite 'clunk' like the front doors. This leads me to think that there may be a CAN bus wire awry somewhere, since there is obviously power getting to the door (please correct me if that's a naive assumption!)

Does anyone have any ideas of where to start looking for a fault? I have scanned with VCDS and the central electronics module has the following faults:

 

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                Address 09: Cent. Elect.       Labels: 1K0-937-08x-09.clb
Control Module Part Number: 1K0 937 085 L    HW: 1K0 937 085 L
  Component and/or Version: BCM PQ35  B+  110 0651
           Software Coding: 4E000AB8A85BB190400A008011000024476000EE425D81605CC5C6000041
            Work Shop Code: WSC 73430 790 00090
                      VCID: 387F266A8B66A78669-806C

 

00930 - Locking Module for Central Locking; Rear Left (F222) 
            008 - Implausible Signal
             Freeze Frame:
                    Fault Status: 01101000
                    Fault Priority: 4
                    Fault Frequency: 1
                    Reset counter: 37
                    Mileage: 364003 km
                    Time Indication: 0
                    Date: 2012.06.01
                    Time: 18:06:03

             Freeze Frame:
                        Term 15 On
                    Voltage: 12.05 V
                        ON
                        ON
                        Term 50 On
                        OFF
                        OFF

00931 - Locking Module for Central Locking; Rear Right (F223) 
            008 - Implausible Signal
             Freeze Frame:
                    Fault Status: 01101000
                    Fault Priority: 4
                    Fault Frequency: 1
                    Reset counter: 37
                    Mileage: 364003 km
                    Time Indication: 0
                    Date: 2012.06.01
                    Time: 18:06:03

             Freeze Frame:
                        Term 15 On
                    Voltage: 12.05 V
                        ON
                        ON
                        Term 50 On
                        OFF
                        OFF

 

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Any help is greatly appreciated!! (P.S. I can only get access to a VCDS dongle occasionally so it is a little hard to repeatedly check on there for any new faults, but is doable if necessary)

Oh one other thing I forgot to mention: Since both doors have gone (presumably - dangerous assumption I know!) at the same time, perhaps it is a problem in the wiring before it gets to either door, and after any other modules that the same CAN bus goes to? If so where would be the best place to start looking for broken wires? (I'm fine with taking door cards off/interior out to get at things etc...)

In the Mk 1 Octavia the driver's door electronics gives the commands for the other doors. Assuming it is the same in Mk 2 then I would look at the wires in the rubber boot where the driver's door runs wires to the body.

There are pictures of this in other posts of broken wires for other functions such as seat air bags wires.

Here's an update on the strangest issue I've ever come across:

 

So after getting hold of the full wiring diagrams for the central locking circuits from elsaWIN, it turns out that the rear door locks are controlled by the central electronics unit directly. So I got to the unit, unplugged it, and plugged it back in (there's 3 52 pin connectors on it) and lo! the rear doors unlocked when I pressed the fob! I thought I'd cracked it! Both doors unlocked and opened fine. So I closed the doors and retested it, but they refused to play ball. Repeating the process several times and the back doors still haven't opened again.

 

This leads me to think that the motors in the doors are absolutely fine, and I have checked the continuity across the wires from the central electronics unit and they are all fine too. So, this leads me to think that it is the central electronics module itself that is to blame. Now, I have been playing around with the central electronics module coding on VCDS over the past few months when I get chance (front teardrop wipe, lane change flashes etc..). So perhaps I have turned something off/on that I shouldn't have done.

 

Does anyone have a base coding/coding for a 1.6 greenline fl octavia mk2, that I could try to see if this is the case?

 

Any help is appreciated!