UK-POLOS.NET - THE VW Polo Forum

Hi,

2007 1.2, 2-door, petrol

I'm hoping someone can shed some light on a weird intermittent fault so I can fix it before it becomes a permanent fault!

The remote doesn't work so we have to use the blade key. Sometimes when you turn the key to the unlock position nothing happens. This would be no more than an irritation... except it happens in both doors.

So far, after many attempts, switching between both doors, one of them will register the unlock. Then both doors unlock immediately and with a healthy sound like there was never a problem at all.

But I'm worried that one day neither will ever register the unlock and we'll have a car that just can't be unlocked.

The battery seems to be fine and charged.

Both doors seem to be behaving in the same way which suggests to me that it's not actually the doors but a common component/system? When it does unlock that seems to be strong and healthy so the fault seems to be on the command side, rather than the unlock mechanism side. I understand that there's a vacuum pump in the boot that the door locks command. Maybe the electrical connections are corroded so the unit isn't getting a strong enough unlock signal? Or maybe the pump motor itself is a bit temperamental? Is that a common fault by any chance?

Or maybe it *is* the door locks and both have dodgy micro-switches that are failing to recognise that the key has been turned to unlock? Is that common?

Any help, advice or ideas much appreciated!

If the problem becomes permanent we could find ourselves with a car that can't be moved blocking the other car on the drive so it can't be used either!!

Cheers,
Dave

Update:
I don't think this car has the vacuum pump - couldn't find it or hear it but did find an electric actuator to lock/unlock the petrol cap access door.

Did all the 2007 models have the vacuum pump based actuator? I reckon this one is all-electric.

The Haynes manual is particularly unhelpful - it just says "take it to a dealer". Does anyone know where the central locking central control unit is? I reckon a clean-up of the contacts on that is worth a go.

Cheers,
Dave

All the 9N/9N3 models are electricly operated
So no pump in the rear.

The microswitches do give some problems over time.
Usually for the door stand (i.e. open/closed/locked/unlocked)

With the key you should be able to open the windows (if electric) so you can enter the unnatural way
Hold the key in the open position to activate them.

I would reccomend to do a VCDS scan of adress 46 messurement block to see the status of the lock and check in 02 Fault codes

Probably have to replace the doorlock itself. Could be done in about 60 to 75 min if you are handy.

Thanks for the info, Maarten, I appreciate that.

It's happened again. This time neither door would open but we figured out how to get in via the boot.

So it's a properly intermittent fault - most of the time both doors register unlock just fine. But then sometimes *both* doors just refuse to register unlock.
The remote fob has never worked, so this is all using the blade in the doors physically.

Given that both doors work most of the time but then *both* fail to register unlock at the same time that suggests to me that the fault is not in the doors but in some common system component.

I've spoken to a local auto-locksmith. He says it's worth setting up a new remote fob and he's 90% sure that will resolve the problem. I take that to mean that the blade will still be unreliable but remote lock/unlock will be 100% reliable.

Does that sound like the best plan of attack??

I know this post is a few months old, but I had a similar experience and found out something interesting that may help some folks with narrowing down central locking system issues.

Just out of interest, did the red 'alarm' LED flash when the doors actually locked? The only reason I am asking is, if it did not, this could indicate an issue with the door lock system, specifically a failed microswitch.

I had a similar problem on my 2008 1.4 Polo, the difference is we knew we had issues with three of the lock mechanisms. Interestingly, since we brought the car, we noted that the little red 'alarm' LED never worked and was something I was going to replace thinking it had failed. The driver's door lock was the worse - it could unlock the doors (that worked correctly), but failed to lock them - a common sign of a microswitch or key drum failure. The key drum had a rebuild kit applied (cheapest option first!) but the issue persisted, pointing to the potential that the 'lock' signal micro-switch in the door lock assembly was the culprit.

I have literally today just finished replacing three out of the four door locks for new, and lo-and-behold, apart from us being able to fully secure the vehicle once more from both driver's and passenger's side, the red LED is now flashing as it should. From this, it could possibly be concluded that the LED also acts as an error indicator for the central locking assemblies (nothing was reported in Vcds scan to indicate any issues on the system).

"No lighty - no likey".......

Now all the locks are working, the next project is to upgrade the 'key only' central locking system to a fob operated system.....