Central locking dilemma

[Garfie]

Hi all, I really hope someone can help with this one.

My friends B5 Avant had the vacuum pump for the central locking pack in the other day. The usual common fault of the impellor shattering.

The part number for his pump is 8LO862257 'G' but he got hold of a 8LO862257 'A' pump from the scrapyard. I'd done some research for him beforehand and found the 'A' pump would work but he wouldn't have use of the central locking from the remote.

He fitted it and all worked again as expected. The central locking unlocked and locked all doors etc from the door lock but not from the remote.

Last night we took the 'A' pump apart and took the impellor out of it an fitted it in his original pump. All parts inside were identical (apart from the circuit board). We then installed it all back in the car.

The problem now is that the original pump will not lock or unlock the passenger and rear doors, either from the remote or from the door lock. Only the drivers door and fuel flap work.

The pump has 2 outlets that connect to vacuum pipes in the car. We have sussed out one outlet connects to a pipe that controls the drivers door and fuel flap, the other outlet connects to a pipe that controls the other doors.
We noticed when comparing the pumps that the outlet for the other doors is blocked off by what appears to be a solenoid operated valve which is inside the pump box, hence why no air passes down this pipe. Just to check we swapped the pipes over and the passenger and rear door locks all operate fine so it's not a problem with those it's just the pump.

Does anyone know how the electrical side of these pumps work and why the pump is not allowing air to pass through the second outlet?

I have also had it connected to VAG-COM and cleared all the faults from when he was swapping the pumps over and none of them come back again.

I also checked the coding and found it has reset to 13166. As his car has the concert radio I reset the coding to 15208 which is the code required for his car with anti hijack etc on. Changing the coding however has not fixed the problem.

Can anyone help?

 

[aragorn]

Depending on the coding it will only unlock the drivers door, then will unlock everything else if you press unlock button again.

Try pressing unlock twice?

 

[Garfie]

Yep we've tried that, one touch unlocking is turned on anyway but it doesnt make any difference how many times we press the unlock button it won't unlock the other doors.

I dont believe it's a remote problem as the same fault shows up when you use the drivers door lock.

Cheers

 

[aragorn]

old_skools your man, hes had plenty experience with the pumps.

Perhaps you've disloged something inside the pump and knackered the solenoid bit?

 

[olds_kool]

if its definatly not the coding and youve cleaned circuit board of carbon dust?
ive repaired a couple that did the same by swapping the gubbins that controls the air flow. (last one the guy had 'cleaned' outlets with an industrial airline and wondered why it didnt work properly)
you need to de solder the 4 wire ribbon then attach the one from the 'A' pump, as youve already noted its only the circuit board that differs
but the wires inside ribbon can be brittle so you could end up with two useless pumps if your not carefull

 

[Garfie]

Thanks for the response olds_kool.

That was what I was thinking may be required. The bit that controls the air flow on the 'A' pump seems to be ok.

Do you know any reason why his 'G' pump has done this or have any knowledge of how this part works as it was fine before swappping them around?

The only other option we have come up with is to splice the two feed pipes to the car together with a T piece and run them from the one working outlet from the pump. We'd have to enable one touch unlock again and just use that to unlock the whole car. So in effect ditching the 2 press unlock feature.

Do you think that would work?

 

[olds_kool]

that should work, the only reason for the two outlets is to enable the security locking option, you should still be able to use auto locking at 10 mph
and you wont be putting any more strain on pump just altering route of flow so could be a better option

no idea why it would stop working but if rest of pump functions perfectly then its worth a go
run time of pump is also adjustable if it needs slightly longer to get to all locks, let me know if you need more info