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packers1712

High current draw

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nige8021
1 hour ago, Pete1 said:

Found the coding table for J519, on Ross-Tech:

http://wiki.ross-tech.com/wiki/index.php/VW_Polo_(9N)_Central_Electronics#Coding

 

 

There are a few adaptations available, listed on the same page, which might be fun to try.

 

 

I think you'll find the you will need the full version to do any adaptions and maybe even any re-coding the "lite version" has very limited functions  

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Pete1

No, I've done both with the registered copy of lite that I own. I think unregistered won't do adaptations though.

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Pete1
On 23/04/2020 at 19:34, packers1712 said:

Good evening Pete,

 

Just been to check what we discussed in the earlier posts and discovered that when I disconnect plug XP4 my high current drops away! Any idea what plug XP4 controls?

 

Also found the thread that I mentioned in my first post its from this forum!

 

https://www.clubpolo.co.uk/forums/topic/266979-battery-drain-problem-9n-12-e-polo/

 

Thanks Doug

 

Well I've got to thank you for this; because I've just done the same disconnect (XP4) on my 9N3 and got the same result.  Quiescent current before was 110mA, immediately afterwards it dropped to 30mA, and half an hour later to 22 approx. I have the same wiring colours going to the same pins. 

 

Just got to work out what the fault is now. Will possibly start by removing and examining the unit, to see if there's similar component damage to what's happened in yours.

Edit: nope no such damage, nor anything else obvious. 

Edited by Pete1
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Pete1

And now I'm embarrassed.  I de-pinned that thinner brown/black wire from my XP4 connector, cos I was suspicious that the interior light system was involved in the current use, but that made no difference, same current when I reconnected XP4 minus that wire. Disconnected XP4 again.

 

I connected up VCDS to look for fault codes in this module but it wouldn't connect...

At that point I looked at a block diagram of the unit's connectivity and spotted that the brown wire on pin 2 of XP4 is the main earth connection to the whole module, so disconnecting that plug just shuts down the whole thing. :sorry:

 

So...then I started to wonder if the high current draw was just because I wasn't testing it correctly.

@packers1712 I suggest you do the following, if this isn't what you did before:

 

Reconnect everything to your Onboard Supply Control Unit

Open the bonnet

Loosen but don't remove the battery negative clamp, make sure you can wiggle it free/off with minimal effort

Flick the bonnet latch over so that the car thinks the bonnet is shut, even though it isn't, giving you access to measure current use directly at battery negative.

Lock the car, all doors. Making sure the key is outside the car.

Wait 30 minutes.

With multimeter on 200mA DC Current range (or similar) and probes in the appropriate meter sockets, put the negative/black meter probe onto the battery's negative post, straight downward. Hold the positive/red meter probe against the battery clamp in such a way that you can keep it on there (and the other one still on the battery post) while you gently jiggle the negative clamp up off the post around your black meter probe so that you now have everything connected through the meter (and the power to the car was never interrupted). This operation is probably much easier with an assistant, but quite doable solo.

 

Read the true quiescent current now.

 

Slip the negative battery clamp back down/on, remove meter probes, tighten clamp. Open up car and operate the bonnet release to reset the catch.

For me, that resulted in a quiescent current measurement of under 10mA.  

I'm not sure whether it's essential to do the locking and bonnet latch microswitch defeat; but both will make the car more likely to think it can fully  'go to sleep'. I think the 30 minute wait is essential. 

 

I'll be intrigued to know if this results in a much lower measurement for you also.

 

 

 

 

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packers1712

Wow Pete that is some test , yes I’ll get on with it tomorrow evening as I’ve been busy in the garden all day and still need to eat tea. I’ll let you know how I get on tomorrow evening!

 

Doug.

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packers1712

Good afternoon Pete,

 

Sorry I never got to chance to have a look at the car yesterday and I'm not sure I'm going to this evening either, so hopefully I will tomorrow just thought I ought to let you know that I haven't lost interest just ran out of time!

 

Doug.

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Pete1

Hi Doug, thanks for the update. I want to offer you one of the two spare units I have, but I'm not really sure whether they are drop-in compatible, with their part number having a different suffix (D rather than C).  I could pre-code one of them to match your present unit (assuming you can read that), and then you could simply install it and see if everything works?  

I doubt it would cost much to post, they are quite light?

 

Let me know if you'd like it, it's just taking up space here really. 

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Pete1

A couple of strands of investigation on this from me today Doug.

 

I set up something so I could watch the current flow through fuse 30 even with doors shut and locked, and sure enough it dropped from around 100mA to 0 some time around 30 mins after closing/locking up the car. So it appears that this control module can and does shut itself down to an insignificant level of current usage, after a time interval.  (I think this time interval is 30 mins by default on a 9N/9N3 Polo, but adjustable with VCDS, referred to as 'Terminal 30G').

 

Measuring the d.c. resistance of the relay coil of the relay (inside the control unit) which supplies the interior lighting , yielded a value consistent with it drawing around 80mA at 14V when energised, which probably accounts for most of this current through fuse 30.  I think this relay is energised as soon as the car is unlocked (or a door opened if not locked?), and de-energised only after 30mins of full closure, so that the courtesy lighting, door lighting, switch lighting etc. is available before key hits the ignition switch, and after it has been withdrawn, without it being permanently on.

 

Of course this may not be why you're measuring what you are, but I think it's quite plausible.  Not sure how this relates to the obvious damage within your module, which may be 100% or 0% related to your measured situation.

 

 

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packers1712

Good evening Pete,

 

I've just carried out the test as prescribed above and it has made no difference to my amp draw its still drawing 0.16A!

Your offer of the control unit is very kind thank you  I'll plug the VCDS in after I've had my dinner and attempt to read the coding of the unit and let you know what that is later.

 

Doug. 

 

 

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packers1712

Pete,

 

The "soft coding" for my central electrics controller is "25742" , I tried to upload a screen shot picture but it says the file was too big!

 

Doug.

 

 

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Pete1

OK, I'll pop one of my spares (the one without any apparent damage anywhere) into my car and code it to that (if it isn't already) and put it in the post to the address that you can advise in a Private Message?

 

Worth a try I reckon. 

 

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packers1712

PM'd you Pete.

Edited by packers1712

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Pete1

@packers1712

Just remembered Doug, the so-called CAN Gateway at address 19 is a sub-module within the Onboard PSU unit.  Don't suppose your scan included showing the coding for this also, just so I can check it too? If you did an autoscan it should be amongst the results, otherwise you'd need to specifically address that module (19). I think it's always coded 00014 on any similar cars I've seen, but it would be good to be sure it's right before I send the unit.

 

I could change any adaptations you want while I'm at it too, e.g. reduce the terminal 30g activation period, reduce wing mirror heating from the default of continuous to - say - ten minutes. Reduce rear screen heater timeout period etc.  Have a look at the last section under the Adaptation heading (for suffix C and later control modules) here http://wiki.ross-tech.com/wiki/index.php/VW_Polo_(9N)_Central_Electronics#Coding

 

 

 

Edited by Pete1

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packers1712

Morning Pete, no sorry I just opened VCDS far enough to see the code on the control unit and I ran a fault code check but that was it.

 

Doug.

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packers1712

Good evening all,

 

Just a quick update on the high current draw saga, Pete has been a massive help and between us we decided that the obviously burnt component on the circuit board of the BCM was the source of the issue so Pete kindly supplied me with another unit (incidentally slightly different part number to the original) but re-coded to match the one originally fitted and it has cured the high current draw - now at 0.01amps by the time all of the ECU's have gone to sleep (which takes approx 1/2 hour on my car)!

 

Thanks for all the feed back and hopefully this will help someone in the future.

 

Thanks Doug.

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