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Diagnosing battery drain issue, voltage drop results

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TUNINGBYAMG

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Discussion starter · #1 ·
Hey guys.

Firstly i'd like to thank members from here who were kind enough to send me the NAV system update.
I did install it, now im to version 0635, was very excited to try and start the touareg v10 the next morning but only to find out my onboard battery's dead again.

Here's what i did tonight
Found and pulled 3 fuses which had abnormal voltage drop on their fuse
1. Fuse 40 left side, control unit in dash panel insert
2. Fuse 4 right side, Telematics/telephone
3. Fuse 11 right side, Radio/Nav

The truck started fine and all looked well without those 3, except radio not working and green light next to ONSTAR not on now.

Any ideas thoughts why the radio/nav will be pulling crazy amounts of power after this latest firmware update?:x I was on 0628 before.

Will give it a go tomorrow morning to see if my onboard has suffered discharge overnight without these culprits

Treg is a 2004 V10
 
Discussion starter · #2 ·
Well more bad news, this morning 12h later after those fuses were removed
battery was dead again. Treg switched to emergency start from backup battery.
I'm wondering, could my onboard batt not hold charge properly
I did charge it, disonnect it and put a load test on it, it seemed to hold
comofortably above 11 volts.
The rear one under the same test made my tester unit glow red..
 
#3 ·
What does your voltmeter on the dashboard read:

1: Ignition on, but do not start, after overnight rest?

2: Immediately after starting the car?

3: 20 minutes into a run?

The gauge isn't graduated enough really so try and estimate if the reading is 14.25V or 14.5V or whatever.
 
Discussion starter · #4 ·
Ok more updates,
noobytoogy, i did look at the startup voltages, when battery is dead i the morning
turning the key without attempting to start indicates a notch before 12v, and if i hold without starting the needle will go towards the 10v indication very slowly. The truck still starts on backup battery however.

I had my onboard battery checked by a special machine at an auto parts store.
It checks out just as good as brand new.

It means i do have a consumer killing it in a short time.

I wonder how bad were the Kessy modules known for eating up the batteries?
 
#6 ·
One battery starts the car, the other runs the "consumers".

When the starting battery fails, it is the consumer battery that takes over . . .

What is the date on the battery? If it is the original, replace it.

If fact, check the dates on both and replace if they are the originals is my advice.
 
Discussion starter · #7 ·
Dont see a relevant TSB for the KESSY or battery drain diagnostics, i have read the one where you have to measure the voltage drop

Forgot to mention, kessy module wakes up every 2-3 seconds and i hear a relay clickin while i was measuring the fuses 30-40 min after alarm was engaged
key was at least 50 ft away indoors at time of test.
 
Discussion starter · #8 · (Edited)
The on board is no more than 2 yrs old, i know because it had a sticker with the order number and the previous owner's name, who by CARFAX history bought the car 2 years ago. So this problem was following from the original owner to the 2nd and to me with nobody able to resolve it.

nooby, i do think in my case its the other way around,
first the truck analyses if i have enough juice in my onboard, if not switching to trunk batt.
Reason why i know this is when its dead, and i turn the key, everything is dead while its cranking from the trunk, and as soon as alternator kicks in, my MFI and headlights and all other consumers power on.
 
#9 ·
For what its worth I have bought two used 2004 V10TDI's (still have both) and both had issues that turned out to be a too small battery installed under the seat (the first V10 was a dealer installed replacement. They put thew rear battery under the seat, moving it to the back and a new factory correct battery under the seat and all was good.

The second 2004 V10 was bought with known issues at a very low price. Same deal on undersized battery under the seat. New dealer battery and electronics are fine! Also I keep a Battery Tender on both battery's on both trucks.
 
#10 ·
I may be wrong but my understanding from others is that the battery in the trunk of a V10 is the starting battery and the one under the seat is for the "consumers".
 
Discussion starter · #12 ·
Thing is my truck starts and tries to run everything from the starter battery once the consumers (under seat) battery has died.
all clocks are reset to 12:00, all settings in computers are lost, feels almost like the truck was dead and starts on a boost
 
#13 ·
From what you have written before you have only had the easy to access battery in the trunk tested.

Have you actually lifted the driver's seat and validated the age of that battery?

If it is the original battery, then even if it tests ok, I would replace it as I'm still of the opinion you have a duff battery.
 
Discussion starter · #14 ·
No thats what i was saying since the beggining, i had them both tested with my tool and
the interior under seat battery removed
1. tested with midtronics system standalone and it checks out almost as good as new
2. confirmed with previous owner it was replaced a year and half ago
3. it did have a sticker with an order number and his name stuck on the side of it when i removed it
 
Discussion starter · #15 ·
Final update, culprit found

pulled fuses for kessy and left overnight, attempted to start more than 16hrs later,starts like a charm and all memory in computers is preserved.

I have a replacement kessy on the way from the liquidation center paid 99$ for it
I will probably attempt to fix mine as well by resoldering new transistors
I do have interior antenna code and in bumper antenna code when scanning it.
Surprisingly the kessy was replaced by previous owner like 2 yrs ago and he paid 1400$ to have it done
 
#16 ·
Battery Drain

Had the same problem. Replaced my two transistors and charged the battery. Not a problem since. No messages while driving, starts better than it ever did. I took mine to two different VW dealers and had every test in the world done to include the alternator and battery cables checked. Transistors cost two dollars and any TV repair person can replace them. Good luck.
 
#17 ·
TUNINGBYAMG said:
Final update, culprit found

pulled fuses for kessy and left overnight, attempted to start more than 16hrs later,starts like a charm and all memory in computers is preserved.

I have a replacement kessy on the way from the liquidation center paid 99$ for it
I will probably attempt to fix mine as well by resoldering new transistors
I do have interior antenna code and in bumper antenna code when scanning it.
Surprisingly the kessy was replaced by previous owner like 2 yrs ago and he paid 1400$ to have it done
Click to expand...
Glad you have it sorted.

Please take some photos of the repairs to the Kessy unit and post as a how-to.

Thanks.
 
Discussion starter · #19 ·
Update 2,

Kessy was taken to a professional electro-technician, he tested the fusible resistors @ 0.22ohms and they all check out, also the 2 Mosfets supplying power also do check out. He's willing to bet that the problem is with the 6 Mini relays (AXICOM) which i have a problem finding on the internet.

Image
 
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TUNINGBYAMG
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