Central Locking woes

[maelgwn]

Hoping you guys can help me out with some troubleshooting here ...

For 6 months + neither of the remotes for my central locking have worked. Started out just one not working - tried changing the battery with no luck and after a period of occasionally needing two tries to work, the second one stopped completely as well. Had to unlock with the key in the door.

Scan of the car gives error code 00470 - Combination comfort Databus in single wire mode. Sporadic 011 - open circuit.

Basically it means there is a dodgy connection/wire somewhere in the comfort Can Bus. However the comfort can bus is supposed to work with only one wire, so not convinced this is the cause of the problem?

And today, I noticed the central locking with the key is not working properly. Locking the car with the key does not lock the back doors (left nor right) but locks the front and boot ok. Pressing the lock button inside the car locks everything ok.

Where should I look next? How do I find the mystery wire problem?

Thanks in advance

Edit: its a 2005 mk5 1.9tdi golf

[vdubmotorworx]

dont worry about the single wire mode fault it makes no difference to the operation.. the convienence CAN can work on only one . it has 2 wires so it has a back up but as its not a saftey system ie airbag etc it will continue to work ok... is there no faults for any of the door locks?. i would get one new remote.. code it up and test from there...VDUB...

[maelgwn]

dont worry about the single wire mode fault it makes no difference to the operation.. the convienence CAN can work on only one . it has 2 wires so it has a back up but as its not a saftey system ie airbag etc it will continue to work ok... is there no faults for any of the door locks?. i would get one new remote.. code it up and test from there...VDUB...

No faults on the door locks - but I only have a cheap scanner, do they sometimes miss things?

And neither of the rear doors work - meaning unlikely to be a fault in the door but somewhere further up in the system I would think?

[vdubmotorworx]

yeh some scanners so miss stuff. doors locks are common on golf 5. but usually the doors are locked and cant be opened when they fault..

[vdubmotorworx]

i would still get a remote working first then see if you have a rear door fault after that. start with that... get the car unlocking via a remote and then recheck whats happening....VDUB...

[Idle]

That one remote failed before the other suggests that the batteries may be low, so my first move would be to change one — they're cheap (CR2023, from memory) readily available on the 'net and from computer shops and not difficult to DIY.

The locking fault could be due to a faulty wire where the cables pass from pillar to door usually the driver's door, which gets the most use.)
It's a well-documented problem, as also are failing MkV door locks.

[maelgwn]

That one remote failed before the other suggests that the batteries may be low, so my first move would be to change one — they're cheap (CR2023, from memory) readily available on the 'net and from computer shops and not difficult to DIY.

The locking fault could be due to a faulty wire where the cables pass from pillar to door usually the driver's door, which gets the most use.)
It's a well-documented problem, as also are failing MkV door locks.

Yes - tried changing the batteries when they were failing without success.

Had a look at the wires in the drivers door (as much as I could see without taking the door card off) - and they looked ok. Would this report as a fault in VAG-COM?

[Idle]

Had a look at the wires in the drivers door (as much as I could see without taking the door card off) - and they looked ok. Would this report as a fault in VAG-COM?

It should, but might not — any break ought to be where the wires actually flex, and may not be obvious.

Look for signs of unevenness or heat marks in the insulation — if you find any, tug at that point and see if it will stretch a bit.

If it does, the wire is likely to be broken (note that the broken ends will make intermittent contact until the ends burn away a bit.)

[maelgwn]

Which module talks to the remotes? Is that the CCM or something else?

[HiTorque]

It should, but might not — any break ought to be where the wires actually flex, and may not be obvious.

Look for signs of unevenness or heat marks in the insulation — if you find any, tug at that point and see if it will stretch a bit.

If it does, the wire is likely to be broken (note that the broken ends will make intermittent contact until the ends burn away a bit.)

If you have problems with driver door lock, check wires in black rubber grommet between the door and chassis.

[vdubmotorworx]

46 convienence unit still on a mk5 .. newer ones are through 09 central electrics...

[vdubmotorworx]

start with one thing at a time.... remotes.. forget the back doors for now.. did the battery have 3 volts? when the battery is in the remote does the red light light up on the remote? if yes to both and you have VAGCOM try and recode the remote as sometimes they can loose there code when its had a flat battery...VDUB...

[maelgwn]

start with one thing at a time.... remotes.. forget the back doors for now.. did the battery have 3 volts? when the battery is in the remote does the red light light up on the remote? if yes to both and you have VAGCOM try and recode the remote as sometimes they can loose there code when its had a flat battery...VDUB...

Ok - thanks VDUB. Ill check battery voltage tonight but red light comes on.

Dont have VAGCOM but will ask Transporter to try programming the keys next time he is around.

[vdubmotorworx]

I actually had one that the battery had 3 volts but it still didn't work, didn't have a remote in stock so just by the off chance I fitted a new battery and all was ok, might be worth getting one anyway as they are only about 4 bucks. CR2025 I think.. it will say on the battery....

[maelgwn]

Well - I finally looked into this some more.

The automotive locksmith said that the remote seemed to work ok (generate a signal and be readable by the car) but he couldn't program it. Tried a new remote and it worked ok, so now I have a new remote.

However it still doesn't lock the back doors.

So, symptoms now are:

Front doors and boot now unlock and lock fine with the remote, key in the door and drivers button.

Back doors unlock fine with the remote, key in the door and drivers button however they DO NOT lock with the remote or the key in the door. They do lock with the drivers button.

When tested through the comfort module, front doors and boot lock ok, however the test stops at the back left door - no response from the lock actuator on this door. Because the test stops it does not try to lock the right side back door.

Does anyone know any differences in how the drivers button works compared to the remote locking? Does the drivers button send a different signal than the Comfort Control Module when locking the car?