No central locking after flat battery

[warpc0il]

Our Octavia battery went a bit flat, due to lack of use over the Christmas break, and didn't have enough go to start the car.

 

Not having a long enough extension lead, I had to remove the battery and bring it indoors to charge.

 

Apart from it being waaay over complicated to remove and refit the battery, this went well and the car now starts and runs fine.

 

However, the central locking won't play any more.

 

She's an early Mk1 (1999) without a remote fob, so the central locking should work from either of the front door locks, or the boot.

Currently the drivers door lock only unlocks/locks the drivers door and the boot.

The front passenger door lock only locks/unlocks that door.

The boot lock just locks/unlocks the boot.

It's impossible to open either of the rear doors, even from inside.

The switch on the inside of the drivers door, that should lock/unlock everything, doesn't.

 

Is this all a coincidence and there's a broken wire or expired component, or has something just got confused from having the battery flat, removed and then replaced?

 

Is there a way to reset or test the central locking?

 

PS. I had searched the forum but could only find threads related to the later cars with remote central locking.

 

 

Edited 10 January, 2019 by warpc0il
typo

[warpc0il]

:bump: ?

[LightRain]

I don't believe it to be because of the battery change, not if it was done correctly.

 

Have you noticed any other unusual electrical behaviour? Do the locks lock and unlock themselves seemingly randomly?

 

What body style is this car and how old? I have come across 2 estate mk1s from 2001ish that have had flooding in the little "hidden" compartment in the left side of the luggage compartment. Both of those cars had odd locking behaviour and indicator/brake light problems.

[warpc0il]

No other strange electrical behaviour, just the central locking, and they're not doing anything random.

 

No issues with any lights etc.

 

Confirmed last night that all three external locks (both front doors and the boot*) also switch on/off the internal courtesy light when they operate, so signals are getting from the locks to whatever controls those lights.

 

I could live with the door locks only working independently but it's a problem not being able to open the rear passenger doors at all.

 

This very early Octavia seems to be a bit of a mix-n-match from the VAG parts bin.

The 1.8L 20V and auto-transmission is from an Audi and certainly some of the electrics are marked "VW".

When the wiper linkage seized a couple of years ago, I replaced the complete mechanism, motor, etc with one from a Mk4 Golf, which dropped straight in.

Are the components for the central locking also common with contemporary Golf/Passat or Audi?  If so, which one?

 

* I've been saying "boot" but it's actually a hatchback.

[warpc0il]

Does the lack of any further responses imply that this is a rare problem or just that there are so few of these cars still on the road (or at least with guys on this forum) that it's totally outside of anyone's experience?

 

Is there anywhere that I can lookup which electrical components this model has in common with her other VAG cousins?

[kentphil1]

To be honest, if this only occured after a battery renewal, it sounds like something is no longer communicating with the drivers door controller.

 

The only surefire way to confirm this is to have the car scanned with something like VCDS, then if something just needs re-pairing, it can be done at the same time.

 

But to be fair, the looms on the drivers door are not the strongest thing in the world and you may have a broken wire there that has just chosen this moment to fail - allbeit freakishly coincidentally. A scan should confirm if the units are not communicating with each other, then you can make a plan from there.

 

Hope it helps.

[warpc0il]

Just out of curiosity, could there be any mileage in just disconnecting the battery, leaving it for a few minutes and reconnecting?

 

Would/could this trigger the components to say "hello" to each other again?

[kentphil1]

In theory it shouldn't matter, but in view of how straightforward it is to do for 30 minutes or so, provided the weather is good for you to work in, what have you got to lose?.

 

Is the barrel on the door getting full travel for the key to operate the solenoid?, with all the bad weather we get, the barrels do start to sieze a bit.

 

That is more the late cars with a remote as we all use the fob, then find the barrel siezed to high heaven because we just don't remember to lube them occasionally in the summer. I presume you use the barrel all the time so it should stay free, but it's still worth a check and costs so little to do.

 

 

[warpc0il]

I don't think it can be down to an individual lock, as none of the three keyholes (front doors & tailgate) and neither of the front door internal handles, operate the central locking, just that door.

 

This is despite them all switching the internal lights off when locking :confused:

 

A thought occurred to me last night, which proved to be correct when we checked this morning - the fuel filler flap release doesn't work either :shock:

 

So, not only can we not get either rear passenger door open, even from the inside, but we can't put any more petrol in the car :(

 

I believe the technical term is FUBAR

[LightRain]

2 hours ago, warpc0il said:

So, not only can we not get either rear passenger door open, even from the inside, but we can't put any more petrol in the car :(

 

There is an emergency release in the boot, right side I think.

 

Is the fuel flap button illuminated properly? What about rear reading lights? There is an earth connection shared by the filler flap release, button illumination and those rear lights. Likely not related, but a quick check worth doing. Also, how about cabin fuse 38?

Edited 22 January, 2019 by LightRain

[FUBAR]

On 22/01/2019 at 11:11, warpc0il said:

I believe the technical term is FUBAR

 

term is what? 

 

I have a 2001 with non remote operated central locking with many of the same issues you have, but generally can get back doors open (O/S/R is hit and miss can be locked for days). In my case I know where a lot of my issues stem from and that is in the control module in the drivers door which I understand is the master of them all. The multiplug that goes into it and likewise inside all the other doors tends to corrode it's pins off. Mine was corroded too far down to salvage and an attempted fix worked for only 6 weeks (4 years ago).

In my mind, car having sat up to allow battery to die, will have also inclined more dampness inside the crap design of the doors themselves. See pics of my drivers door multiplug etc. Sometimes people get lucky and can save the pins before they rot off, but if it's not been done since leaving the factory 20 years ago, it's a big gamble, could be a few still working but ready to come apart if unplugged. I'd start in drivers door as it talks to all other locks and then move to front passenger. You might get lucky and find it all manky, clean and rears open, if not it's a pain to get door cards off while closed. I keep mine with all screws that go around the edges off just the 2 big screws that are behind the interior door handle so if it happens to me sometime (which im shocked it hasn't already) I can still get them off to get in there.

 

Realistically, what I am intending to do is just decommission the central locking totally and pull the fuse so all doors are old school that way rears won't deadlock when locking with key so will still open from inside and I should be relatively safe. I am on my 3rd drivers door lock barrel at moment and 4th will need to go in soon I can feel.  Today similar to you, but opposite side, I can lock car from drivers door (all locks with O/S/R sometimes not), but unlocking key physically turning will unlock drivers door only, boot and passenger barrels will do all except drivers door. As I am physically turning lock in drivers door without the micro-switch as soon as it's hit throwing the central locking in to do the rest, it's wearing hard on the barrel(s), but they are dirt cheap. Multi-plugs and wiring between doors and car in the grommet is where I'd be looking first.   

[J.R.]

I ended up scrapping my much loved MK1 for the same problems, intermittent tailgate not unlocking, fuel filler flap then finally all 3 passenger doors deadlocked.

 

I had no corrosion on any of the connectors, continuity across all wires in door loops, was fairly certain that it was the central convenience module, no corrosion problems there, replaced it with a supposedly tested S/H unit and no change to door locking and remore fobs didnt work (expected) gave up and bought a MK2.

 

Now having a MK2 I realised that its far more complicated and unreliable in electronic terms and owning and mastering VCDS is a necessity, in 14 years I had never needed it on the MK1 but if I had had it I am convinced I would have found the problem I had, most likely a communication problem to the CCM or failure of CCM and I could have recoded the new one to work on my vehicle.

 

My advice is to buy VCDS and find the fault, it will pay for itself many times over, failing that ask a fellow member withb VCDS to scan your vehicle.

[FUBAR]

1 hour ago, J.R. said:

I ended up scrapping my much loved MK1 for the same problems, intermittent tailgate not unlocking, fuel filler flap then finally all 3 passenger doors deadlocked.

 

I had no corrosion on any of the connectors, continuity across all wires in door loops, was fairly certain that it was the central convenience module, no corrosion problems there, replaced it with a supposedly tested S/H unit and no change to door locking and remore fobs didnt work (expected) gave up and bought a MK2.

 

Now having a MK2 I realised that its far more complicated and unreliable in electronic terms and owning and mastering VCDS is a necessity, in 14 years I had never needed it on the MK1 but if I had had it I am convinced I would have found the problem I had, most likely a communication problem to the CCM or failure of CCM and I could have recoded the new one to work on my vehicle.

 

My advice is to buy VCDS and find the fault, it will pay for itself many times over, failing that ask a fellow member withb VCDS to scan your vehicle.

It's funny you should say that, I wanted to replace the module in drivers door but would need to code replacement, VCDS of late can't communicate with it and when I go to CCM I get same timed out response. Could be my issue right there. 

[kentphil1]

As the CCM can't communicate with VCDS, i would start by making sure that you have a good quality connection on both sides of the fuse blade for the circuit. Corrosion on the back of the fuse board could be preventing the CCM from getting full voltage.

[warpc0il]

Quote

 

Lot's of info to work with there and some clues as to where to start looking.

 

I'm up to my armpits in other stuff atm so the car's going to an independent VW/Audi/Skoda specialist in the morning, along with a printout of this thread.

 

Spooky that I declared it "FUBAR" not knowing that was also a members handle on this forum.

Even more spooky that Fubar had the same issues, and is located in NI 

Anywhere near Groomsport?

[FUBAR]

4 minutes ago, warpc0il said:

Lot's of info to work with there and some clues as to where to start looking.

 

I'm up to my armpits in other stuff atm so the car's going to an independent VW/Audi/Skoda specialist in the morning, along with a printout of this thread.

 

Spooky that I declared it "FUBAR" not knowing that was also a members handle on this forum.

Even more spooky that Fubar had the same issues, and is located in NI 

Anywhere near Groomsport?

Originally from Bangor, but now about as far as is geographically possible within NI lol. 

[warpc0il]

Okay, so it looks like we've got it sorted.

 

The culprit was the motor that drives the tailgate lock.  This motor was very stiff and taking way too much current.

Not quite enough to blow the fuse but enough to play havoc with the rest of the system.

The short-term fix was to disconnect the motor, which meant that the tailgate lock worked manually but at least the rest of the locks worked together, including the rear passenger doors, and the fuel filler release operated.

Now we've replaced the tailgate lock motor and it's all working as it should, at least most of the time, as the rear offside passenger door is still a bit lazy.

This may be because it hadn't seen any action for a couple of months, so I'm just going to keep an eye on it while it gets some more regular exercise.

 

I'd like to thank those of you who took the time to suggest potential causes, as that still helped with the diagnosis, even if it was a process of elimination.