Hi everyone,

I've had a battery drain for the last few months, and its between 0.2-0.3 mA which is quite high, but when the F30 fuse is pulled the drain lowers to 0.04 mA which is the volkswagen standard, noticed when i put the fuse back in theres a clicking noise which I'm guessing just confirms that it is the fuse circuit that is causing the problem. Thought it was the power control module originally but tried another unit and the same fuse was still causing a drain. When disconnecting XP4 plug on the power control module also lowers the drain to acceptable standards. Any ideas what could be on this circuit ?

Any help would be greatly appreciated.

Edited 29 November, 201114 yr by chelseaash

Hi everyone,

I've had a battery deain for the last few months, and its between 0.2-0.3 mA which is quite high, but when the F5 fuse is pulled the drain lowers to 0.04 mA which is the volkswagen standard, noticed when i put the fuse back in theres a clicking noise which I'm guessing just confirms that it is the fuse that is causing the problem. Thought it was the power control module originally but tried another unit and the same fuse was still causing a drain. When disconnecting XP4 plug on the power control module also lowers the drain to acceptable standards. Any ideas what could be on this circuit ?

Any help would be greatly appreciated.

what circuit is the fuse protecting?

Hi everyone,

I've had a battery deain for the last few months, and its between 0.2-0.3 mA which is quite high, but when the F5 fuse is pulled the drain lowers to 0.04 mA which is the volkswagen standard, noticed when i put the fuse back in theres a clicking noise which I'm guessing just confirms that it is the fuse that is causing the problem. Thought it was the power control module originally but tried another unit and the same fuse was still causing a drain. When disconnecting XP4 plug on the power control module also lowers the drain to acceptable standards. Any ideas what could be on this circuit ?

Any help would be greatly appreciated.

what circuit is the fuse protecting?

It says engine management in the haynes manual, but to complicate things the XP4 plug on the power control module has 5 wires, three to do with wipers (but had new indicator stalks) 1 earth (p31) and the interior light (but tried removing that so not interior light)... On the f5 fuse wiring diagram shows the 429 relay ( have taken this out then pulled fuse and still has clicking noise)

Edited 28 November, 201114 yr by chelseaash

Sounds like a faulty relay draining.

A question: which relay controls the wiper modules in the 9n and are your wipers working properly?

PoloD.

Hi,the wipers are working fine,there is a click when the wipers first activate but think this is normal?. Wondered if wiper motors are common ?

Just pulled the fuse that is causing the problem (supposed to be engine management). And here's what is and isn't working when it's pulled out. Working: headlights, sidelights, main beam, puddle (door) lights, and the engine starts... Not working: indicators, wipers, interior light, dash lights, hazard switch, rear screen demist. Apparently the fuse layout listed on the internet is for left hand drive so the fuse isn't f5 but f30 which is for the power supply unit !!!! Any help is greatly appreciated.

Edited 29 November, 201114 yr by chelseaash

I would try to find where the ticking is coming from. Try removing the fuse and feel around from any vibration as you reinsert the fuse.

Also I think hazard light switches are a common fault, but that may be the 6n2, however it's worth a try.

Hi thanks for the reply,I am finding it impossible to trace this drain.The XP4 plug on the power supply/convenience unit stops the drain and the fuse is f30(power supply unit)which also stops the drain.When the fuse is pulled the items that don't work are wipers/indicators/dash lights/hrw/hazards,I could do with a proper wiring diagram or what components are on this circuit,or has anybody else had this problem,could be power supply unit as when I tested with a spare unit it was still showing a drain but presume that this unit will stay "live" while the door is open etc ??????

Hi thanks for the reply,I am finding it impossible to trace this drain.The XP4 plug on the power supply/convenience unit stops the drain and the fuse is f30(power supply unit)which also stops the drain.When the fuse is pulled the items that don't work are wipers/indicators/dash lights/hrw/hazards,I could do with a proper wiring diagram or what components are on this circuit,or has anybody else had this problem,could be power supply unit as when I tested with a spare unit it was still showing a drain but presume that this unit will stay "live" while the door is open etc ??????

Problem solved!! would never of guessed it but it turns out the car was waking up in the night because the control module/ convenience unit was coded to have rain sensitive wipers, which it hasnt, so i guess you could say my car was having nightmares about rain sensitive wipers haha.

thanks for your help everyone!

Very strange. Do polos even come with rain sensors?

Glad you solved it.

Very strange. Do polos even come with rain sensors?

Glad you solved it.

I thought that 2002 polos were too old to have that technology, but it seems to have solved the problem. no wonder it took us that long to find the cause

Hello,I know this is a long shot,but my polo has a battery drain identical to your problem,tracked it down to same fuse,I know you said it was a rain sensor issue,can you remember how you resolved this 

Many thanks 

Mark

First Welcome to the forum.

24 minutes ago, Mark Bennett said:

Hello,I know this is a long shot,but my polo has a battery drain identical to your problem,tracked it down to same fuse,I know you said it was a rain sensor issue,can you remember how you resolved this 

Many thanks 

Mark

 

The OP hasn't been on the forum since 2013 so I doubt they will see this and respond

@Mark Bennett What year is your car?

 

There has been recent thread on similar lines that even referenced this one I think.

After much toing and froing, a burnt out component or two on the Onboard Supply control Unit was found (and photographed) by the OP.  Replacing that control unit with a secondhand one fixed the issue.  May be worth taking a look at your circuit board to see if there is similar damage.

 

See here: 

 

Its a 54 plate,where should I look to find the unit 

More or less vertically above the accelerator pedal.

Thank you for the info I will take a look at it hopefully this is the problem, I was hoping it was something to do with the black box the insurance had fitted

Oh, could easily be that, they're usually pretty careless about how they bung those in. When I bought my 9N it had one hacked into the light switch wiring. Find it and see where the feed has been taken off?  It ought to be something that's only powered when the ignition is on/engine running, but if there's a quicker, easier way to get it running they'll surely take it.

Hello again,I've located supply box there seems to be a couple of non standard wires,connected to the loom,1 had a fuse,pulled it no difference on draw other I is a non fused spur with thin wire going into 1 connector on supply box,I'm guessing these are to do with black box,with car shut down,if I pull supply unit fuse this drops to 0.02,would the lower figure be average draw,with fuse in reading 0.12,

20mA or 0.02A is the ballpark for how much current the car should be drawing from the battery when everything is shut down correctly. 

120mA suggests something isn't shutting down correctly.  I'll have a refresher look at some wiring diagrams later and see what I can suggest.  Did you try to get into that unit, or struggle to unplug the connectors?  They're all keyed in such a way that it's not possible to put them back in the wrong places, but can be a bit awkward to disconnect them if they've never been undone.

 

Hi,I managed to get unit out,had a go at unplugging connectors but was concerned about breaking something,I must have upset something as the airbag light comes back on after a few seconds,I think I'll have another check in case a wire's been pulled or something. 

Thanks for all the help it's very much appreciated, it's really starting to needle me now 

Did you switch the ignition on while there were connectors unplugged? That's the usual cause of spurious airbag lights. Check that all the connectors are back in fully, I seem to remember one of the back ones being easy to miss due to visibility/lack.

As far as I can remember car was shut down,I will check all the connections over the weekend, I might even attempt to remove all the connectors so I can give unit a good  once over,I'm sure I'll need to tap your knowledge yet again 

As far as I can remember car was shut down,I will check all the connections over the weekend, I might even attempt to remove all the connectors so I can give unit a good  once over,I'm sure I'll need to tap your knowledge yet again 

Update,removed unit,opened it up and it doesn't look too healthy on a soldered connection,last small one on xp5 connector,black &sooty,so I'm guessing i might have found the culprit.

Checked all wiring connections but still getting airbag warning