Troubleshooting .78 amp Battery Drain - 2006 Subaru Legacy Outback

[battleborn]

Hello everyone,

 

I've been reading every post I can find on this topic and have spent a good bit of time pulling fuses! It seems like I've got some twists to my problem that are unique, and I've got some specific wiring questions, so hopefully starting a new post is appropriate.

 

First, what started it all: the battery goes dead after sitting for 2-3 days. We just got the car about six months ago, so the first time this happened I checked the charging system and replaced the battery. It's doing it again, and obviously this isn't good for the new battery!

 

So - cleaned electrical connections, charged battery, made sure all interior lights/acc are off, checked all door switches. Found out my old multi-meter (that I bought ten years ago or so) was acting funky, so went and got another one. Disconnected battery cable and placed multi-meter inline with setting at 200mA and got - zero. That's not right. So I put it to the 10A setting and it eventually settled out at .78 amps. Wow. No wonder I'm having trouble, right?

 

I've gone through the fuse box and pulled EVERYTHING one by one. The problem is intermittent. Sometimes it'll show a drop to .35 or so, but if I recheck it the .78 drain is back. The only thing that's made a solid difference so far is removing the 120amp SBF from the main box under the hood.

 

I'm trying to figure out where the SBF 120 fits into the wiring, and my Haynes manual is less than clear about it. Unfortunately I don't have access to a factory service manual. I found one for an '06 Impreza online and it looks like it's for the Power Supply Circuit, assuming similar wiring in my car. 

 

Is this correct?

 

I've disconnected the alternator with no result, and also the headlight relays (shown on the power supply circuit diagram). Will start to trace the wiring further, but wanted to make sure that I'm barking up the right tree here.

 

Also, isn't .78 a lot of draw? Seems like there should be a really obvious cause here.

 

Also, that same Impreza diagram shows another SBF 30amp joined into the charging circuit. Anyone know where this is located so I can check it?

 

Diagram attached. Thanks in advance for any help.

[idosubaru]

if i'm reading that correctly then yes that's a huge draw.

 

1.  have you pulled EVERY single fuse out of the interior cabin and the engine bay fuse box?  all of them, pull them and see if the draw goes away.

2.  are there any aftermarket items - stereo or otherwise?
3.  any components not working or working oddly?

 

as a temporary measure they have mechanical switch designed to put on the battery terminal at any auto parts stores so that you can disconnect the battery every time and at least drive the car without killing your battery all the time. 

 

the 120 is just a main power supply circuit so i don't think that narrows it down much.

[1 Lucky Texan]

the parking lights aren't on are they? check the 'virgin switch' on top of the steering column. (still have those in 06 I guess???)

 

as said above, aftermarket stereo amplifiers/sub or lighting etc. I dunno if any 12V power ports are on with key off in an 06, but it may be worth examining the bottoms of them for trash, chewing gum wrappers w'ever.

 

listen carefully for any clicking relays or humming sounds.

[battleborn]

Thanks guys, good advice.

 

I haven't pulled every fuse out yet, will do that when I get home tonight.

 

No aftermarket items at all. Everything is unplugged from cabin power ports. 

 

The CD player (which is integrated with the heater controls) did freeze up a while back and I haven't been able to get any of the CDs out of it. Figured that it would be easier to listen to the radio and eventually add a mini-phone line in than to fix it, so haven't bothered to pull it out. That's the only thing that has been acting up at all.

 

I don't remember a switch on top of the steering column, but will check that too when I get home. Haven't heard any clicking relays or humming, but yes, keeping an ear to the ground for that.

 

Thanks for the tips. I've been banging my head against a wall on this for a few days now. Helps a lot to have some more eyes on it.

[1 Lucky Texan]

some folks have reported CD players trying to 'cycle' or eject continually. But I'd expect you would hear that, and, of course, pulling the stereo-related fuse should pinpoint that.

 

good luck

[Fairtax4me]

The control units stay powered after you reconnect the battery.

Remove the negative cable and wrap a large gauge wire around it (strip the ends about 3-4") wrap the other end around the negative post on the battery. Place the negative cable on the post and cycle the key to ON then back off two or three times. Wait 10 or 15 minutes for the control units to power down. Now remove the negative cable making sure the wire does not lose connection with the cable or post. Hook up your ammeter, then remove the wire. Now you can check for draw without the control units pulling extra current.

[battleborn]

Fairtax4me, thanks!  

 

That's a great tip. It's likely causing my intermittent readings as well as contributing to my excessive draw readings since I'm essentially hooking the battery up every time I check the drain. Also explains why it usually spikes to almost one full amp before settling down to .78 amp. I found an official Subaru doc outlining the same procedure, but didn't get a chance to try it last night. Your explanation made much more sense anyway. But here's the document just in case anyone else with a similar problem finds it useful.

07-62-072 Dark Current or Excessive Battery Draw .pdf

[Fairtax4me]

That's how I knew the wire trick. I've done it a few times on cars at school and it works pretty reliably.

If that doesn't bring the draw current down to under about 350mA pull the fuse for the radio to see if the CD player issue is causing a problem. If that doesn't change it, don't put the fuse back, mark where it came from (draw a picture of the fuse box if tou need to) and pull the next fuse, keep pulling fuses and lay them off to the side until you find the one that makes the biggest difference.

[battleborn]

Got home and did the wire trick as fairtax4me mentioned above. And guess what - that problem is solved! Current dropped down to 229mA. 

 

From what I've read, sounds like that is within normal range. So this whole issue doesn't seem to actually have anything to do with a battery drain.

 

The alternator is charging at 14+ volts. I wasn't worried about the battery before because it had just been replaced. But now I'm thinking that it may have a bad cell or something. Going to yank it out and take it back to the place we bought it. Hopefully they'll exchange it, and I'll keep a close eye on it from here on out. 

 

Anything I'm missing? Thanks for everyone's help. This board is awesome.

[Fairtax4me]

Sounds like a bad battery. However, you should consider getting a replacement from a dealer. A lot of newer cars need a newer style of battery that is designed to hold a charge longer with the moderate drain caused by the multiple control units in the car. I don't remember exactly what the name is for them, but the chemistry inside is a bit different.

Anyway, the new battery may have died because it is the wrong type for the car. See if the dealer recommends a certain type, you might even find they have a better price on the one you need.

[Cougar]

If 229ma is a real number and you really meant to say 22.9ma then you have a problem. That amount of current is about 10 times what it should be normally if everything is in the sleep mode. That is almost a quarter of a amp of current draw. I'm not sure how long it takes systems to go into the sleep mode once power is connected on the newer cars. You might try waiting up to around 10 minutes after power is connected to see if that current drops further down when something else drops off. If there is more than 50ma of current draw when everything is in the sleep mode I would try to find out what is drawing the extra current. Normal currnet draw on the older cars is around 20ma but I'm not sure if the newer ones draw a little more or not.

 

I don't think you have a bad battery. There is too much current drain on it.

 

As far as your old meter goes I suspect you blew out the fuse when you were in the 200ma current range and that is why you saw no current flow. The power circuit was now open due to the blown fuse. You will need to replace it. You have to very careful when you use that range since 200ma is very easy to go over when looking at current draw for car systems. Meters usually have protection fuses for both the low current range (200ma) and the high current range. Measure unknown currents using the high range first before going to the low range if it is needed to get a better resolution so you have an idea how much current is being drawn.

[battleborn]

Well, the place where we bought the battery tested it and exchanged it since it was only a couple of months old. Put in the new battery last night.

 

You're absolutely right about my old multi-meter, it had a blown fuse...but not from this project, must have been blown for a while because I never got a good reading out of it, and it just has one reading for amps up to 10 with three decimal points. Was thinking the same thing though, so bought a replacement fuse yesterday and was able to return the other one. Used old meter in all my tests last night and it worked fine. The reading was actually .229 amps, but now I'm doubting myself and meter so I'll double-check that before I go too much further.

 

Good thing I slept well last night thinking the problem was solved. Once I saw the lower amount of drain, just figured that was it! For what it's worth, I did let the car sit for about ten minutes or so before I took the reading.

 

Can someone perhaps confirm what a stock newer Legacy (this is a 2006) should have for battery drain? As Cougar said, the old cars had a 20mA drain. What should I be looking for?

Edited February 20, 2013 by battleborn

[doc526]

According to the document for troubleshooting that was posted above, 150 milliamperes should be the maximum draw in standby.

 

I would think that since Subaru posted that in 2008 and it says that it is for all models it should be good for the 06 model.

Edited February 20, 2013 by doc526

[battleborn]

I ran the drain test again just to confirm. About the same as before. 225mA or .225 amps. 

 

Didn't have a lot of time before wife had to leave for work, but I pulled the fuses one by one in the engine compartment fuse box with no change. Didn't pull any relays.

 

Started to pull fuses in the cabin, but the first one I pulled (unit IG 1) resulted in a drop to .07 amps or so. That's all I had time to do this morning...will try to find the right wiring diagram for that fuse/circuit today though and pull the rest of them this evening.

[Cougar]

When I look for current drains I like to see numbers below 50ma as a normal number. Even 150ma of current drain seems too excessive to me but that is what the info sheet says. I have wonder if that number is really a normal amount for a standard car. When accessories like a remote starter are added to a car that can have a significant change on the standard current drain. If you have a remote starter system installed I suggest you disconnect it and see what the current draw is then.

 

Most of the fuses in the dash shouldn't have an effect on the current drain since they normally are cut off from power by the ignition switch. Apparently you found a fuse that is hot and pulling it out caused the current drain to get a lot closer to a normal level. Even with 70 milliamps draw I would still try to find what is causing that amount of draw.

 

Pulling relays shouldn't make any changes normally since they should be turned off but it is possible that something at fault could be turning on a relay when it shouldn't be turned on. The trouble isn't with the relay but there is something wrong in the relay control circuit.

 

Job well done with your meter fix. From what you say about, it sounds to me that the meter is working well and you need to trust yourself. You are doing the right things. Good job.

[battleborn]

Thanks for the feedback, much appreciated. 150mA does seem like a lot to me as well, but this is the newest vehicle I've ever owned so it's fresh territory.

 

First thing tonight I'll pull the relays under the hood and see if that changes anything. 

 

Since the stereo has been acting funky, anyone know offhand which fuse is on it's circuit? The labels on my fusebox don't indicate.

 

Was thinking of going through the interior fuse box, seeing which fuses were hot with a test light, and pulling those. Should save pulling a lot of fuses that, like you said, are cut off by the ignition switch anyway.

[idosubaru]

+1 triple digits sounds too high.  the subaru's i've measured...though olde rhan yours...seem more around the 30 and 40 range, i wouldn't expect 5 times that even if yours is a little higher.  i'm also notably not well versed in electrical talk though, you are in good hands with Cougar, he's who i always hopes peeks in on my electrical questions!!

Edited February 20, 2013 by grossgary

[Cougar]

Thanks for the vote of confidence Grossgary. Persistance pays off in these kind of issues.

[battleborn]

Well folks, I'm as confused as a baby in a strip club.

 

Hooked up the meter again this evening. Started by pulling all relays in the main fuse box under the hood. No results. Same reading, about .22A. 

 

Then, pulled each fuse in the main box and put them back as I went. No change.

 

Next, pulled all the fuses in the cabin fuse box. Took them out and replaced them one row at a time. No change, including the one that I pulled this morning that resulted in a drop. Should mention that I taped the door sensor closed while I was doing this.

 

Next, pulled every fuse out of the main box, all at once. No change. Put 'em back.

 

Removing the big fuse (120amps) in the main box drops the reading down to .001amps, but I'm guessing that's because nothing in the car has power without that.

 

But just in case, hooked up the meter to battery and terminal of said fuse. Got same reading, which would seem to indicate that it's nothing in the wiring between the battery and that fuse at least.

 

 

I'm stumped. Ideas? Thanks to everyone for all the help so far.

Edited February 21, 2013 by battleborn

[battleborn]

Heh. Well, got a couple more clues. Wife just told me that the check engine light came on today, and the cruise control light kept coming on and off whether the button was on or not.

 

'Course, would have been nice if she had told me this before I spent an hour messing with it.  But at least it's a direction.

 

I'm going to pull the check engine light codes and take a look at the cruise control circuit, and will of course post back with any progress.

[Fairtax4me]

I know the cruise will be disabled if the Check Engine Light is on with certain codes, but I don't know if that would cause the indicator light to blink.

Is the on/off button for the cruise control located on the steering wheel? Kinda wonder if that could be a clock spring issue...

[1 Lucky Texan]

did she buy gas recently? might be a not-tight-enough gas cap.

 

on the drain issue, I have no idea if it makes sense but, what about disconnecting the alternator and starter wires?

Edited February 21, 2013 by 1 Lucky Texan

[Cougar]

Since you pulled out the fuses in the main panel under the hood and the problem was still there then that limits the problem area down a lot. Try removing the main lead to the alternator and see if the current draw is still there after that is removed. That lead is hot to the battery so I suggest you remove the negative battery lead before you work on it and then isolate the wire end so it can't touch anything and short to ground when you reconnect the negative battery lead.

[battleborn]

Didn't have a chance to do anything with the car yesterday. But she drove it all day and the check engine light didn't come back, and the cruise control hasn't flickered.

 

Cougar and Texan, I did try disconnecting the alternator wires early on in this process, but that was before I knew the proper way to check for current draw with the wire to maintain battery connection.

 

I'll check it again tonight when she gets home and report back. I'd be excited if it was the alternator...easy fix!

[Cougar]

If a blocking diode fails inside the alternator it can cause this kind of problem and the path can be overlooked. Since the starter solenoid has to be working for current to have a pathway to ground that path isn't possible unless someone has added an extra power connection to something at the battery connection to the solenoid.