Subaru Outback Forums banner

Dark current drain

2145 Views 56 Replies 16 Participants Last post by  Flyboy182
I think I have found the cause of the current drain that was killing my battery in my 2017 Outback. I performed a draw test at the battery negative terminal, with the following results: The current draw would drop to approximately 25ma after just 3-5 minutes, but if I watched it for a short while the amp draw would bounce up to as high as 3.0 amps, and then cycle back down to the previous 25ma level. It would do this repeatedly. I began to pull fuses from the underhood fuse box one by one, until pulling the DCM (#9) fuse caused the fluctuations to stop completely. Leaving that fuse pulled, I road-tested the car which appears to me to have all systems functioning. A little on-line research taught me that that fuse only powers the Starlink module, and that the car will work just fine without it, unless you require Starlink to function (I don’t).
l have not experienced any more low battery symptoms since I did this.
1 - 20 of 57 Posts

· Premium Member
2016 Tungsten Outback 2.5l Premium w/ES, OP 14, PP #4
Joined
·
549 Posts
I, too, found the DCM the dark current culprit on my 2016. If not driven 4- or 5-days battery would discharge to point of not starting the vehicle. In my case I did loose the in-car microphone for answering calls when connected to BT. All other functions work.
 

· Registered
2012 OB , 2017 Impreza
Joined
·
4,841 Posts
Question: Does this 'drain' only happen if one has a starlink subscription?

Also... it is well-known that cellular-devices only use just enough power to communicate with nearest tower. (tower-close = less power..... poor-signal= more battery drain)
I wonder if the starlink system also uses similar power-consumption algorithm?
 

· Premium Member
2021 OB Touring, 2011 OB Premium
Joined
·
2,284 Posts
Question: Does this 'drain' only happen if one has a starlink subscription?

Also... it is well-known that cellular-devices only use just enough power to communicate with nearest tower. (tower-close = less power..... poor-signal= more battery drain)
I wonder if the starlink system also uses similar power-consumption algorithm?
We live in an "RF hole" and cellular signals are iffy, at best (one to two bars, max). We have had no issues with "dark current" draws from the Starlink system or for that matter, anything else. However this does sound like a feasible reason behind current drain.
 

· Registered
2017 Outback Limited 2.5L CVT
Joined
·
22 Posts
Discussion Starter · #8 ·
I, too, found the DCM the dark current culprit on my 2016. If not driven 4- or 5-days battery would discharge to point of not starting the vehicle. In my case I did loose the in-car microphone for answering calls when connected to BT. All other functions work.
I went back and checked my in-car microphone functionality, and found it to be now inoperative, just like yours. I don't find this to be a big problem, as I don't like to use my phone very much while I am driving, for safety's sake. It's certainly not worth $1000.00 or more for a new DCM just to make that work. Everything else seems to work as before.
I love this car, but I am not impressed with the fact that manufacturers install these systems that have these built-in defects that cost such ridiculous amounts of money to correct. It shows, to me, that they are more interested in devising new ways to extract/extort money from their customers than they are in looking after their customers' best interests. There is no good reason on earth why a small box filled with silicon chips should be worth THAT much money. These parts are very rapaciously priced, in my humble opinion.
 

· Registered
2017 Outback 3.6R
Joined
·
564 Posts
I went back and checked my in-car microphone functionality, and found it to be now inoperative, just like yours. I don't find this to be a big problem, as I don't like to use my phone very much while I am driving, for safety's sake. It's certainly not worth $1000.00 or more for a new DCM just to make that work. Everything else seems to work as before.
I love this car, but I am not impressed with the fact that manufacturers install these systems that have these built-in defects that cost such ridiculous amounts of money to correct. It shows, to me, that they are more interested in devising new ways to extract/extort money from their customers than they are in looking after their customers' best interests. There is no good reason on earth why a small box filled with silicon chips should be worth THAT much money. These parts are very rapaciously priced, in my humble opinion.
The microphone module requires +5v to power it.
You can tap it off the back of your headunit and wire both the mic and front speakers directly to the headunit. This lets you completely remove the starlink module from the car. Or atleast unplug it.
 

· Registered
2017 Outback Touring 87K
Joined
·
385 Posts
Could the battery in the DCM be the cause of a current drain? It's calling for a charge, but won't hold a charge and needs replacement? $63 at the dealer.

Someone posted a thread about this recently, IIRC.

 

· Premium Member
2016 Tungsten Outback 2.5l Premium w/ES, OP 14, PP #4
Joined
·
549 Posts
Could the battery in the DCM be the cause of a current drain? It's calling for a charge, but won't hold a charge and needs replacement? $63 at the dealer.

Someone posted a thread about this recently, IIRC.

May have been me. (see link) I've got a spare battery ordered via ebay ($20+/-) that appears to be like the one others are showing . Of course it's on the preverbal slow boat from China PLUS have family visiting so won't remove radio until they are gone and replacement battery arrives. Radio removal looks relatively straightforward. I used Subaru Radio removal as a guide. It appears the DCM is mounted on the radio's bottom
 

· Registered
Joined
·
8 Posts
I think I have found the cause of the current drain that was killing my battery in my 2017 Outback. I performed a draw test at the battery negative terminal, with the following results: The current draw would drop to approximately 25ma after just 3-5 minutes, but if I watched it for a short while the amp draw would bounce up to as high as 3.0 amps, and then cycle back down to the previous 25ma level. It would do this repeatedly. I began to pull fuses from the underhood fuse box one by one, until pulling the DCM (#9) fuse caused the fluctuations to stop completely. Leaving that fuse pulled, I road-tested the car which appears to me to have all systems functioning. A little on-line research taught me that that fuse only powers the Starlink module, and that the car will work just fine without it, unless you require Starlink to function (I don’t).
l have not experienced any more low battery symptoms since I did this.
I have a 2019 Outback and it's been not starting a few times recently. I took it to Subaru this week and they said it was a parasitic draw, caused by the DCM. They explained the DCM as what powers the OnStar and SOS buttons to me. I don't use either of those features. They said mine is testing at almost double the allowed draw amount. They are going to order a part for me to fix it, but there is no ETA on when the part will arrive. There is currently none in the country, and they said it could be months. They warned that my battery would probably continue to drain, so advised me to just not drive the car if I can. Currently I have taken the car to my parents house and my Dad just unhooked the battery and it's sitting there, while I drive the spare family car. Well off the record the service agent that was helping me told me I should be able to pull the fuse associated with this temporarily and it would cut power completly to those OnStar and SOS buttons, and therefore not draw battery power when the car is off. I looked up the fuse diagrams and its just the DCM fuse in the engine compartment, correct? Fuse #9. My plan would be to pull that so I can continue to drive my car without the battery draining, until they can get the part in and fix the issue. I want to fix the issue because they warned me that if I didn't the car would be considered "modified" and it would affect resale value and if Subaru of America would cover issues or recalls. Just wanted to see if anyone could advise on if I pull the DCM fuse what else (besides the OnStar and SOS buttons) may be affected. I have read things saying pulling a fuse can cause a lot of features to not work. Thanks in advance!
 

· Registered
2015 3.6R Limited w/ES
Joined
·
5,387 Posts
...I looked up the fuse diagrams and its just the DCM fuse in the engine compartment, correct? Fuse #9. My plan would be to pull that so I can continue to drive my car without the battery draining, until they can get the part in and fix the issue. I want to fix the issue because they warned me that if I didn't the car would be considered "modified" and it would affect resale value and if Subaru of America would cover issues or recalls. Just wanted to see if anyone could advise on if I pull the DCM fuse what else (besides the OnStar and SOS buttons) may be affected. I have read things saying pulling a fuse can cause a lot of features to not work. Thanks in advance!
If you read the first post of this thread you'll see that pulling #9 has worked for the OP. Crazy the dealer didn't just do that for you temporarily.
 

· Registered
Joined
·
8 Posts
If you read the first post of this thread you'll see that pulling #9 has worked for the OP. Crazy the dealer didn't just do that for you temporarily.
Yeah, I kinda thought the same thing! They said that they would get in trouble from Subaru of America if they did it or told me about it. The girl that is helping me literally walked way out in the parking lot with me and told me off the record. Can you clarify what OP means?
 

· Registered
2015 3.6R Limited w/ES
Joined
·
5,387 Posts
Yeah, I kinda thought the same thing! They said that they would get in trouble from Subaru of America if they did it or told me about it. The girl that is helping me literally walked way out in the parking lot with me and told me off the record. Can you clarify what OP means?
Ok, yeah, that's what I figured. OP is a forum acronym for "original poster" or "original post" (post #1 of the thread).
 

· Registered
Joined
·
8 Posts
Ok, yeah, that's what I figured. OP is a forum acronym for "original poster" or "original post" (post #1 of the thread).
I just want to know if I pull that DCM fuse what else is going to be affected. I can deal with not having certain features work temporarily til they fix everything, if it means I can still drive my car without fear of the battery being drained and it not starting!
 

· Registered
2019 Subaru Outback Limited 2.5i WGM
Joined
·
263 Posts
In addition to the microphone, you might also notice that the front speaker audio is affected; this depends on the generation of DCM used in your Outback.

I want to fix the issue because they warned me that if I didn't the car would be considered "modified" and it would affect resale value and if Subaru of America would cover issues or recalls.
This is pure "FUD" (Fear, Uncertainty, and Doubt) from the dealership. There is no way that SOA could possibly refuse to fix a safety recall item based on the removal or disabling of the DCM. And the dealership should first try replacing the $60 DCM battery, which is quite possibly the cause of the excessive current drain, instead of replacing the whole DCM. This is a lithium ion battery, and it may be failing to charge properly, which causes constant drain on the main +12V battery.

It is not fair that they are asking you to repair something you don't need or want. I removed the DCM from my 2019 Outback within a few months of buying it, bypassed the +5V to the microphone, and the speaker audio connections, and have had zero problems since then.
 
1 - 20 of 57 Posts
Top