[Corbett]

I know there are a ton of threads here but I cant seem to find the answer Im looking for.

I bought my 07 V10 TDI Treg about 2 years ago. My first winter of owning the Treg the batteries started to die in the cold weather. I decided to replace both batteries and did not have an issue until the following winter. Replaced both batteries again under warranty. I am now on my 3rd winter and the batteries seem to drain again after sitting for a few days.

I pulled the batteries again last week and had them tested. They diagnosed the battery under the seat to be dead and they replaced it. The rear battery seemed to be fine.

Here I am a week later and the car will not start with push to start but only with the key in the ignition and sometimes even that takes a few tries.

Ive read about the charging system and am interested in bypassing the relay that tells which battery to charge via alternator so that both are charging in parallel. Does anyone have any more info on this?

I have also checked all 4 of my door handles and they seem to be functioning properly.

Thanks guys!

 

[4ePikanini]

I know there are a ton of threads here but I cant seem to find the answer Im looking for.

I bought my 07 V10 TDI Treg about 2 years ago. My first winter of owning the Treg the batteries started to die in the cold weather. I decided to replace both batteries and did not have an issue until the following winter. Replaced both batteries again under warranty. I am now on my 3rd winter and the batteries seem to drain again after sitting for a few days.

I pulled the batteries again last week and had them tested. They diagnosed the battery under the seat to be dead and they replaced it. The rear battery seemed to be fine.

Here I am a week later and the car will not start with push to start but only with the key in the ignition and sometimes even that takes a few tries.

Ive read about the charging system and am interested in bypassing the relay that tells which battery to charge via alternator so that both are charging in parallel. Does anyone have any more info on this?

I have also checked all 4 of my door handles and they seem to be functioning properly.

Thanks guys!

Keyless entry?

Is your key stored in close range to the vehicle? If so, the car will never fully go to sleep, which means a larger drain.

 

[Corbett]

The key is stored in the house and the car is in the driveway. Maybe 50 ft from the vehicle with several walls inbetween. I can test that though thanks!

 

[Singh]

something not right, have you run a vcds scan?
my 2006 v10 still has original starting battery and the auxiliary still had life in it but was changed about two years ago as a measure before going on a remote outback trip.

 

[lgibson]

I would check those door handles with VCDS. Go into address 46 and look at 08 Measured Value Blocks (MVB’s) for each of the Part Numbers. If they are all reporting closed the next step would be measuring drain at the fuses. VOA put out a four-page Technical Bulletin 27 07 11 2016076 addressing this battery drain issue. Or you could just take a chance a buy a new Kessy. Or you could do the Kessy MOSFET replacement shown in our DIY section.

 

[nickyt]

Start with a VCDS scan. If you don't have antenna errors, the kessy is fine. It always throws the antenna errors if/when a rebuilt is needed.

If it is not the kessy, check the door handles. The little black switches can go bad and cause the car to not go to sleep. The most common thing is that the car will randomly lock or unlock. The switches can short open, closed, or become intermittent when they randomly act like someone pushed the button. The intermittent problem is a real pain to troubleshoot, but usually you start seeing the "Switch to Park" message when that happens.

After the kessy and door handles are deemed good, you start looking for a rogue current draw.

How often are you running the V10? I recommend at least one trip of fifteen minutes per week, if you wish to have healthy batteries. One trip of at least 10 minutes per two weeks is the minimum that these vehicles will tolerate. Any less then that and you need to be using a maintenance battery charger. CTek is my personal choice.

 

[Corbett]

I would check those door handles with VCDS. Go into address 46 and look at 08 Measured Value Blocks (MVB’s) for each of the Part Numbers. If they are all reporting closed the next step would be measuring drain at the fuses. VOA put out a four-page Technical Bulletin 27 07 11 2016076 addressing this battery drain issue. Or you could just take a chance a buy a new Kessy. Or you could do the Kessy MOSFET replacement shown in our DIY section.

Just went to 46 then mvb 08. Found all the outiside door locks and it says not operational unless I press the button then it says functioning. No errors in the module though.

 

[Corbett]

Start with a VCDS scan. If you don't have antenna errors, the kessy is fine. It always throws the antenna errors if/when a rebuilt is needed.

If it is not the kessy, check the door handles. The little black switches can go bad and cause the car to not go to sleep. The most common thing is that the car will randomly lock or unlock. The switches can short open, closed, or become intermittent when they randomly act like someone pushed the button. The intermittent problem is a real pain to troubleshoot, but usually you start seeing the "Switch to Park" message when that happens.

After the kessy and door handles are deemed good, you start looking for a rogue current draw.

How often are you running the V10? I recommend at least one trip of fifteen minutes per week, if you wish to have healthy batteries. One trip of at least 10 minutes per two weeks is the minimum that these vehicles will tolerate. Any less then that and you need to be using a maintenance battery charger. CTek is my personal choice.

I drive it once or twice a week usually only an hour or so each time.

 

[nickyt]

Ok. If no antenna errors (which you will see in any VCDS full scan) and no problems with the black buttons, the next thing to look for is a rouge current flow.

Aftermarket anything such as radio or nav systems should be looked at also.

 

[Corbett]

Ok. If no antenna errors (which you will see in any VCDS full scan) and no problems with the black buttons, the next thing to look for is a rouge current flow.

Aftermarket anything such as radio or nav systems should be looked at also.

I do have an upgraded RNS-510 in the treg. But it definitely turns off when car is off and shut completely down after Ive been out of the car for a bit as it should. So strange

 

[lgibson]

I hope you can find VW’s TB mentioned in post #5.

 

[tdsg]

I had similar problems with my 2006 V-10 TDI and eventually traced them to the Webasto auxiliary heater hidden under the front fender. Although my car had none of the interior controls as described in the "Controls and Equipment" section of the furnished Owners Manual, VW continued to install the Webasto heater- which burns diesel fuel - in some if not all V-10s destined for export to North America, and at the very least, in my car. I was continually losing my starter battery and then one day noticed a low humming noise coming from the left front wheel-well. The noise was coming from the circulating pump of Webasto heater and our quick solution was to remove the fuses from the circuit that supplies the "auxiliary" heater and pump: Fuse Box Left: Position 2 (5A). Position 4 (20A) and Position 48 (5A). Apparently the circuit board had malfunctioned and was starting the heater, or at least the pump, spontaneously. I think, but have been unable to confirm, that the Webasto in my car was configured to provide some degree of freeze protection for the block. I have a replacement heater on hand, but since I now live in coastal California and no longer travel to Edmonton, Alberta on a regular basis, I haven't found the time to remove the fender liner and replace the malfunctioning unit. If we move to South Lake Tahoe, as my wife would like, I'll be revisiting this issue before the next winter. Be aware that I am not a dealer, nor a trained VW mechanic, so if I have misstated anything in this post, I would appreciate the kind correction of any such errors.

 

[noobytoogy]

I think the Webasto was installed on all V10s.

If you specified the preheat option when ordering the car you got the cabin controls, otherwise you didn't.

Regardless, the main purpose of the Webasto was/is to help heat the coolant as quickly as possible upon starting the car - diesels are slow to warm up - and get the engine up to operating temperature along with heat for the cabin.

I think the Webasto was standard on all the Generation 1 diesels for the foregoing reasons.

Certainly over the years there have been quite a few buyers of used Gen 1 Touaregs whose first post on the forums on the first cold day they've had the car has been "Help, there's steam coming out from under my car this morning!"

I believe the Generation 2 diesels got an electric heater as standard and an Eberspacher if the preheat option was specified when the car was new along with a 100 litre tank as opposed to the smaller, standard 85 litre tank though the tank size varies according to the market the cars were sent to.

 

[tdsg]

Thanks for the updated information on the Webasto auxiliary heater in my 2006 Touareg.

I have close to 300,000 miles on my car, although I have to admit to installing an engine and transmission salvaged from a donor Touareg that was rolled and totaled with 55,000 miles on the engine, when my car had accumulated about 185,000 miles. The primary reason for the swap was that the tandem pump(s) at the rear of the camshaft of my original engine had failed and were leaking oil all over the exhaust manifold. Since the largest part of the repair was the R&R of the engine, it made sense, at least at the time, to install a younger engine and transmission, as well as replace oil-soaked components of the front axle and suspension, with parts from the donor.

To be honest, the car has not been inexpensive to maintain and operate, but the thought of losing the power and control available to me with this car, particularly when towing a trailer throughout the western states and Canada, makes the expense of maintenance far more bearable. It is my favorite car of all time and I've been on the road since 1964, with pickups, low-beds, mini-and full-size SUVs, family sedans and just about every other type of vehicle available in sunny California since then. I will really miss this car when I finally have to give it, or my driving license, up...

 

[noobytoogy]

Great post with the history. Glad you've stuck with it!

 

[lgibson]

I think the Webasto was installed on all V10s.

If you specified the preheat option when ordering the car you got the cabin controls, otherwise you didn't.

Regardless, the main purpose of the Webasto was/is to help heat the coolant as quickly as possible upon starting the car - diesels are slow to warm up - and get the engine up to operating temperature along with heat for the cabin.

I think the Webasto was standard on all the Generation 1 diesels for the foregoing reasons.

Certainly over the years there have been quite a few buyers of used Gen 1 Touaregs whose first post on the forums on the first cold day they've had the car has been "Help, there's steam coming out from under my car this morning!"

I believe the Generation 2 diesels got an electric heater as standard and an Eberspacher if the preheat option was specified when the car was new along with a 100 litre tank as opposed to the smaller, standard 85 litre tank though the tank size varies according to the market the cars were sent to.

All great info!
Beginning in 2006 NA V10’s were furnished with circuit board (7L6 815...) that would not support “parkheizung” (cabin heating) and with no N279 valve for switching between cabin and engine. I suspect our NTSA regs over fear of folks suffocating themselves in garages were the reason. (These were the folks who outlawed turning headlights and mineral fluid in auto braking systems to protect us) You could/can not buy the proper 7L6 819 ... Webasto in NA. Our member “V10” authored the original retrofit thread here on this forum. We got our 819’s and the matching console timers from friends in Europe. I still love triggering the Webasto 30 minutes before leaving the house when it is below 39 F outside. Hate to admit I have never used my console timer after the initial install.

 

[Corbett]

Update. First cold week of the season haven’t driven the egg in a few days. Went to run to store and car wouldn’t start via push to start on the first try. Cranked then stopped. Started right up with key in ignition. These are always the same signs it will only get worse as it gets colder. Still stumped on this issue but something is clearly draining the battery when the car sits, but only in cold weather.

 

[nickyt]

The tsb mentioned above is available.

I would also listen to see if I could hear the heater running, as in the post above.