battery drain ?

[tinca]

Hi guys,  I have a problem with my electric windows on my 2017 subaru forester, which may be the reason for my Battery draining . The Battery is less than 18months old,  and have had no problems with it until yesturday . whilst out on a fishing trip , the car stood all day and because it was hot i opened the tailgate and lowered the windows down a bit. In th evening i shut the tailgate but forgot to shut the side windows..the following morning l couldnt open the tailgate, then found i couldnt start the engine ..the Battery was comletely flat, not even any ignition lights. i got a friend to jumpstart the car so i could drive home.. thing is, the passenger window dont work, cant open it..this has never been an issue before..somehow the problem with the windows has caused a complete Battery drain. l would welcome any suggestions.

Alan  

[Mr B]

Is it power tailgate ?
Is well known issue on parasitic draw of the tailgate when left open .
Once the Battery totally dead the window/body control module likely lost reference position of the side window thus it will not operate and possibly need window learning/reset procedure carried out .
Modern cars are 30 grands worth of cables computers and sloppy electrical engineering/programming that completely avoidable mistakes and generally pointless garbage concepts that not needed to start with  .
We hardly see any issues with models from 90's to 2005, newer you go the more unreliable high cost and stupid it gets .
If I don't like the engineering and component quality I won't own it, all my vehicles are 2 decades old, have almost zero stupid faults and almost zero repair costs year after year .

[tinca]

Appreciate your input Mr B.  Not a power tailgate, so at least that rules that out. I know what your saying about modern cars . I'm old enough to remember the relatively easy to fix motors 70sthrough to 90s .,cars these days are designed not to be easily fixed by the owners.. still a bit of a mystery as to why the Battery drained completely flat ! 

ive just tried starting the car, all seems well, started ok. the window which didnt work , (passenger front door) from drivers side, does now but only after l opened and closed it a few times from the passenger door button..so all seems well at the moment. fingers crossed ...thanks again for your contribution Mr B. 

[Mr B]

Basically fully opening and closing is pretty much part of the window learning procedure .
don't fully rule out the rear hatch as possible still linked to that and when latch recognised open the related modules stay awake thus sapping power .  another factor would be boot light .
We had a few issues in related to the power tailgate . Window switch on this era also known faults and is a recall on certain part number switches, garbage window control engineering compared to anything up to around 2010 .
It not so much the complexity of modern vehicles that the issue it the poor engineering thought and constant mistakes at electronic design and software programming mixed with constant striving effort make everything as profitable as possible basically resulted in designed failure to rape the consumers bank accounts every way they can, amazingly people also seem quite content keep buying modern rubbish and believe it environmentally better lol ! .
 

[Pete_W]

I have a '19 Outback. Battery drain was sorted by a Subaru mod. Dealer had to fit it - after they had been pushed a bit and ordered the bits.

Seems tailgate open keeps the canbus wide awake and draws maybe 4 amps continuously. So, with a perhaps half-life Battery, a few hours will kill it.

With the mod it still draws 4 amps, but only for about 20 minutes.

[Mr B]

^
Yes ridiculous engineering mistake .
I was under impression it power tailgate only but it might be the latch lock  open keeping modules active .
This the problem with modern cars across all brands ... a lot of features and tech thrown at it with poor levels of engineering and testing yet more effort and engineering in making sure components materials and assembly can be maximum profit potential leaving the customers with over priced short lifespan high maintenance and faulty from factory products ...

[Justin Time]

On 6/26/2022 at 11:39 AM, Pete_W said:

I have a '19 Outback. Battery drain was sorted by a Subaru mod. Dealer had to fit it - after they had been pushed a bit and ordered the bits.

Seems tailgate open keeps the canbus wide awake and draws maybe 4 amps continuously. So, with a perhaps half-life battery, a few hours will kill it.

With the mod it still draws 4 amps, but only for about 20 minutes.

Hi Pete.  Really well done.  That's of interest to me with a 2020 OB.  Can you share what the modification was and how did you get the dealer to replace it (warranty)? Cheers.

[Pete_W]

Hi Justin,

Check out https://www.subaruoutback.org/threads/2017-2019-power-rear-gate-prg-control-module-design-change-fixes-battery-drain-problem.527080/

It looks like this is for up to MY19 so it may not be relevant to your MY20.

The dealer (Budgens at Shrewsbury) just did it when faced with the TSB number and the fact that I had measured the current draw.

Subaru seem to work on the basis that if you don't complain, then you havn't got a problem, but respond OK if you do complain.

[Justin Time]

On 6/29/2022 at 10:51 AM, Pete_W said:

Hi Justin,

Check out https://www.subaruoutback.org/threads/2017-2019-power-rear-gate-prg-control-module-design-change-fixes-battery-drain-problem.527080/

It looks like this is for up to MY19 so it may not be relevant to your MY20.

The dealer (Budgens at Shrewsbury) just did it when faced with the TSB number and the fact that I had measured the current draw.

Subaru seem to work on the basis that if you don't complain, then you havn't got a problem, but respond OK if you do complain.

Thanks Pete.  That's really helpful.  I'll get this sorted too.