Jump to content
Ultimate Subaru Message Board

2001 Subaru Legacy L Wagon Battery Drain


Recommended Posts

I have a 2001 Subaru Legacy L Wagon with an infuriating battery issue. I'm sure more people will immediately say search the board there are lots of other topics relating to this but rest assured I have spent the day searching the board, as well as Google, reading and trying everything I'm able to. However, if I've missed something please feel free to post the link. Here's the background: purchased in the spring of this year with no problems. Since it started to get cold the last couple weeks it has had trouble starting and finally would not start. A couple of times I had gotten it started by shifting into neutral but this may have been a coincidence as it doesn't work anymore and doesn't jive with everything since then. Lights, dash, etc would turn on and were bright but no crank, no start, no click, no nothing. Had the battery tested and it was dead. After a charge it had 10% health and was quickly losing its charge. Bought a brand new battery and the car started instantly and worked great. Within two days I was in the same situation: lights bright but no start. Got the new battery checked and the health was 100% and held a charge. Car started great. Battery died again within two days. Obviously something is draining the battery. When the car is off the drain on the battery is only 0.02 amps, so well within the good range from what I understand. The alternator is kicking out nearly 15v when the car is started and the battery was near 13v when the car was off, following a full charge to the battery. I used the diode check function on my multimetre to check the indirectly test the diodes on the alternator. Long shot I know but I'm grasping at straws. With the main wire to the alternator disconnected, touched my one probe to the bolt where the wire connects and the other touching the casing. In one direction I got an infinite reading and the one direction I got 0.455. I repeated this a few times and got the some readings. I scratched into the metal for both to get a good reading. I'm not sure what the diodes in the alternator are rated for but I thought the readings might be low and if one or more are damaged they could possibly be draining the battery when the car is off even if the alternator is charging while the car is running. I'm read but at wit's end trying to figuire out what is draining the battery. Any help would be great!

Link to comment
Share on other sites

If you have a bad diode you'll have excessive AC voltage on the charge lead.

Set your meter for AC while the engine is running and the lights on. Should have less than 0.1v AC. Anything above that will indicate a bad rectifier diode.

You may also consider taking the car to a parts store and get them to run an alternator test on it. It's best to do this when the engine is hot since a cold alternator can still show a good charge, which will lower once the alternator is hot.

Link to comment
Share on other sites

Thank you for the advice. I'll give it a try tomorrow night after work since it's dark already and starting to snow! I kind of hope that's it so I can just fix it and be done with it. Other than that I'm at a bit of a loss as to what is draining the battery. Cross you fingers!

Link to comment
Share on other sites

Try leaving the battery disconnected for the period of time it's usually dead by. Reconnect and see if it starts. It's possible the first battery was indeed faulty, then the replacement is poor quality or has issues. car-part.com has alternators for roughly $80 which might be cheaper than outright buying a reman. Also, you aren't leaving phone chargers, Ipod, etc. in the 12v socket are you? Are the doors/hatch closing tightly at night? Those are things I check 1st.

Edited by Bushwick
Link to comment
Share on other sites

Well, new developments. Snow storm so I wasn't able to try right away what Fairtax4me mentioned and now the car won't start at all. The battery is good; charged it over night last night, took it off the charger this morning and left it off the car. This evening it was still coming up at just under 13v so it held a charge. I checked the continuity from the + terminal to the bolt on the starter and it was good so I'm not sure what is going on. The oil level is high so I'm wondering if the pressure is stopping it from starting (cranking either, no noise). However, back to the original problem. I can't check the alternator when the motor is running because the motor won't run but when I hooked up my multimetre (with the car off) between the bolt on the alternator and the cable from the battery it read 22 or 21.9 ACV depending on which ACV setting I used (750 and 200 respectively) which I'm very much thinking that should not be reading seeing as the engine is off. Possibly I found my power drain which makes me happy but others can confirm this as I'm learning as I go. Any thoughts or suggestions on either issue? Thank you again for all your help so far!

Edited by potter2010
Link to comment
Share on other sites

Oh to followup with Bushwick's suggestions, the dome and truck lights are turned off so unless they are shorting out nothing there and there is nothing plugged into the power outlet and nothing visible in there. The glove box latch is broken (thanks to -50c weather and plastic) but the light is off when the car is off. Everything seems to close well as the draw on the battery is only 0.02A when everything is off and closed but thank you for the suggestion and I'll look up the website. Thanks!

Link to comment
Share on other sites

Can't check ACv with the engine off. Those are useless numbers. The "ghost" in the wires.

 

Battery can show 12+ volts unloaded but it may not have the amp capacity needed to start the car. I had one that showed 12 volts charged but dropped to about 4 volts trying to crank the engine. Wouldn't do anything except make the starter click once or twice.

 

The real test is to watch the voltage while cranking the engine. If it drops to less than 10v the battery is not holding enough amperage.

Link to comment
Share on other sites

I just went to go see if the voltage dropped down when I turned the key and low and behold the car started. I'm kind of scratching my head at that one. The only thing that changed was the battery voltage was down slightly from my trying to start it several times earlier. Either way I took photos of my readings off the alternator as Fairtax4me mentioned. The multimeter is a pretty cheap one i'm using until my new one arrives in my mail so the accuracy may not be 100% but should be in the ballpark. I performed the test with the lights on and off. With the lights off I got 21.7 and with the lights on I got 21.6/5.

 

WS_MM_1.jpgWS_MM_2.jpg

Edited by potter2010
Link to comment
Share on other sites

I'll let Fairtax talk about the readings, but are you saying you tried to start, and got nothing (no turning over)? Or did it at least click (starter getting power)? Then you left it alone, went back, it cranked and started? If that's the case, you might have 2 different issues appearing simultaneously. Is it a manual trans or auto? Mine (auto) will only start in "N" or "P". There is a switch that prevents starting if in R, D, 1, 2, or 3 if auto. Manual trans would be a bad neutral safety switch. I'm wondering if yours is failing and not allowing the car to turn over on occasion. If/when it happens again (if auto trans) try putting in neutral and cranking; try taking out of park and running through the gears, then back in park and see if it starts. Dunno where the switch is on the manual trans, but it should be easy to bypass. Also unsure where the auto's safety switch is, but I'd look at this as a possibility for the no start symptoms.

Edited by Bushwick
Link to comment
Share on other sites

Ahhhh, I've been doing some reading previously about the safety switch and was wondering about that but I got side tracked with the battery/alternator as my possible issue but maybe there is two. There was no turning over, not even trying and that has happened before but I've been blaming it on the battery. When the car doesn't start it generally doesn't try to turn over, just nothing happens or on occassion a half second of it trying to turn over. As far as I can tell there was no clicking but it's hard to tell with the background noise. We move up North earlier this year and are currently live in an apartment building with outside parking so it's not that quiet but as far as I can hear there's no clicking. It is an automatic and on a couple occassions, especially before the situation got this bad, it would start if I shifted it to neutral. This only worked on two or three occassions so it might be a coincidence. Also the problem is been getting worse since the weather has gotten cold though that might be a coincidence as well. I'll have to search around and read more about the safety switch but if anyone has advice or resources I'd be happy to hear or be pointed in the correct direction.

 

I'm interested to hear what Fairtax4me has to say about the voltage but if I did it correctly I'm guessing it's WAY off where it should be.

Link to comment
Share on other sites

If it started in Neutral before after not starting in Park, and you are getting NO clicking, I suspect the no start is the safety switch or maybe an issue with the wiring. It's called a "range sensor" on rock auto for auto trans. I know Ford has these and the symptoms are the same. Should be on the actual trans somewhere. 

 

http://www.rockauto.com/catalog/x,carcode,1375084,parttype,4584

 

The $2 sensor is for manual trans unfortunately. I inputted a 2.5L engine in the search as I wasn't sure what yours has.

Edited by Bushwick
Link to comment
Share on other sites

I can't tell in the picture, is the charge lead disconnected from the alternator?

If it is then that explains the strange reading.

When the alternator charge lead is disconnected it will keep running up the output voltage because the system voltage, which is fed back through the wires in the plug, is not increasing as the alternator is attempting to charge. The voltage regulator steps up charge voltage until it sees the system voltage increase. It can go well over 100V given the right conditions.

 

Connecting your meter leads between the output post and charge lead, as it appears you've done in the picture, is showing you the difference in potential (voltage) between the output post and the charge lead (which goes to the battery at the other end), not the amount of voltage the alternator is producing.

A voltmeter works by showing the difference in voltage between two points. If you put both probes on the positive battery terminal it will show 0v. Because there is 12v potential on each probe, there is no difference in potential, which the Voltmeter displays as 0v. It's a 0V difference between those two points.

 

To check for stray AC voltage output from the alternator it needs to be connected as it normally would be (charge lead securely fastened to the output post). Start the engine, ground the black meter lead to the battery negative, and touch the red meter lead to the alternator output post.

 

An Alternator only produces Alternating current on its own (hence the name) so it has to use a group of diodes (usually 6, called a Rectifier Bridge) to convert that AC into DC. They do a pretty darn good job too, if there is any stray AC getting past a brand new rectifier bridge it will usually be less than 0.1v. If a diode shorts there will be a large amount of stray AC, anywhere from about 2.0 - 10v. Generally if there is more than 0.5v AC output it means there is a problem developing.

Link to comment
Share on other sites

I. Lights, dash, etc would turn on and were bright but no crank, no start, no click, no nothing.

 

this does not sound like a battery/alternator issue.

 

1)  it's probably the range sensor for the gear selector.  next time it does it - simply move this selector back and forth through the gears a few times, trying in neutral again.  it'll probably start.  that sensor is going bad.

Link to comment
Share on other sites

1)  it's probably the range sensor for the gear selector.  next time it does it - simply move this selector back and forth through the gears a few times, trying in neutral again.  it'll probably start.  that sensor is going bad.

 

I beat you to it a couple posts up :P Also, his battery was going dead at times after sitting overnight.

Link to comment
Share on other sites

I beat you to it a couple posts up :P

 

You did, thought one should be told if they are in a competition!  I replied to add diagnosis. Subaru's almost always start by jiggling/wiggling the button/shifter. I've never seen or heard of a Subaru that will not start because of the inhibitor switch. Surely it's possible but it would be rare on a Subaru.

 

Also, his battery was going dead at times after sitting overnight.

 

It seems like it but there have a few comments not typical of a drained battery:

 

 Lights, dash, etc would turn on and were bright but no crank, no start, no click, no nothing.

 

Within two days I was in the same situation: lights bright but no start

 

that doesn't sound like a dead battery, which has also been tested....implying the battery is good.

of course i've seen batteries act odd, be weak and new...and even test fine when they weren't...

 

i think some good diagnosis is still in order to determine if this is a battery issue, starting issue, or charging issue...

Link to comment
Share on other sites

I might agree with the suggestion that this is two different issues and that would explain some of the oddities. However, I am not an expert so I will bow to popular opinion. I performed Fairtax4me's test suggestion correctly this time (I hope!) and the readings are not good if I'm on the correct setting and all. Alternator is hooked up, - probe on - terminal of battery, + probe on alternator post. The car was running and the lights were turned on. Now Fairtax4me mentioned that it could be up to 10v and this is nearly three times that and certainly above the 0.5ACV that it should be below. I'm curious if I did something incorrectly since it is much higher than expected or if the alternator is REALLY malfunctioning. I'm happy to hear the opinions of those with more experience.

Oh, I wanted to add if someone is questioning the wires coming off the battery terminals those go to a 1.5A trickle charger I picked up about a week ago. This was not plugged in/operating during the test, especially as the car was running at the time.

 

WS_MM_3.jpgWS_MM_4.jpg

Edited by potter2010
Link to comment
Share on other sites

As long as the meter is working correctly that should be an accurate number.

Plug the meter leads into a wall socket in your house and compare the meter reading to what your home ACV should be, 110-120 / 220-240. If this shows an accurate reading the meter should be working correctly and you should start looking for an alternator.

 

If you would like a second opinion, find a parts store that will do alternator and battery testing and have it tested.

Link to comment
Share on other sites

Before I say anything else I want to say thank you everyone for all the help. It's really appreciated and I'm learning quite a bit. I'm slowly increasing past the 'oil-change' level. This is my first car and hopefully I can keep it going for at least a few more years!

 

Back to the matter at hand. I'm in the market now for an alternator, either online or from a shop. I hooked the car back up to my battery tester today and obviously the volts were a little low but when I started the car to check the charging system which had read decent before it was barely made it onto the scale. It was very slowly increasing and when I revved the engine it would push the needle into the green but then drop back to red when it was idling. I'd definiety say the alternator is shot, expecially combining the ACV and this recent battery test.

The neutral safety switch may be another matter but I figure I'll get the alternator installed and go from there seeing as the switch is going to cost me around $100 I figure but i'll have to check around on different sites.

Thanks again and I'll post any new developments or how the alternator install goes. :)

Link to comment
Share on other sites

awesome, glad you tracked it down.  you are dead on - start with the definitive known issues first, which in this case is the alternator.

 

subaru has new remanned alternators for like 1996 Legacys for like $70 due to a recall.  probably a different plug which would need swapped to match, but a low cost alternative to aftermarket gambling.  i don't know that new aftermarkets are any more high percentage than used OEM units.

 

www.car-parts.com is a used parts database for north america.

Link to comment
Share on other sites

  • 3 weeks later...

Well, the new alternator is in, actually was about a week and a half ago but I've been away. I was originally going to go with a used one but with me going away I wanted to have it installed before I left. As a result the only one I could get in time was a bit pricier but it was remanufactured with a warrenty versus from a wrecker so might be worth it. It was pretty easy to do since the location is easily accessible. The car has been starting very well, actually better than since we bought it in February so that's great. The trickle charger is still being used and now in conjunction with the block heater and battery warmer due to the cold (up to -40c at night and dropping). I figure it can't hurt having a little extra charge overnight. Since the alternator has been installed there hasn't been any no start/no click/bright lights issues that may have been a neutral safety switch issue so maybe it was all battery/alternator related we'll have to see. Apparently while I was away my wife smelled gas when she started up the car on a couple especially cold days so I'll have to check into that and the acceleration tick that's always been there that I'll tackle in the spring. Otherwise she's running great!

Thank you all for your help and suggestions. Everyone was a great help, though I should give special mention to Fairtax4me.

 

S_SUB_ALT.jpg

^New Alternator^

  • Like 1
Link to comment
Share on other sites

Well hopefully things are okay now with the new alternator installed. The current drain of .02 amps is right where a normal current draw should be so that isn't a problem. A common place for a current drain problem to occur is the CD player getting jammed. But again your test proved that wasn't a problem.

 

In a earlier post you stated you measured 21.9 VAC even while the engine wasn't running. The reason you got that reading is due to the design of your meter. It doesn't block the DC component while in the AC volts mode. It is just something you need to be aware of when you use a meter. Usually higher end meters will block the DC so the meter would have shown zero volts in that case. You can add a series capacitor (about a .02ufd) in one of the probe leads and that would block the DC but still allow the AC to be measured.

 

Another place that can be a problem and make it seem the battery is low is the inhibit switch and the starter solenoid contacts. Vehicles around 10 years old commonly will have worn out solenoid contacts which is usually determined by hearing a fairly loud click when you go to start the engine. While the solenoid is working the contacts are worn and not allowing power to get to the starter motor windings. The contacts can be replaced in that case. When the inhibit switch has a problem, power can't get to the solenoid and you won't hear the loud click of the solenoid working. Sometimes just physically adjusting the switch position can fix that problem.

Link to comment
Share on other sites

  • 6 years later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...