Intermittent battery light on

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tjrob2000
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Intermittent battery light on

Postby tjrob2000 » Sun Jan 20, 2019 10:32 am

2007 G35 Journey sedan.  A few months ago the battery light came on and when I put a voltmeter on the battery with the car running it was at 11.9vdc so I suspected the alternator since I had recently replaced the battery.  Got an alternator from a local rebuilder/reseller in San Antonio (a new Hitachi part, not rebuilt) and installed it and all was well for awhile.  After about 3 months or so the battery light came on again with the same voltage reading.  Thinking I got a faulty alternator I removed it and took it back to the vendor.  They tested it and it looked fine with current up to 160A.  I got to see them test it so no faking it.  Put it back in and all was well, or so I thought.  IIRC the voltage was in the 13.5 - 14vdc range.  This was somewhere in the september timeframe.  Since then the light has been coming on anywhere from every few weeks to a few days.  It goes out after a few minutes of driving and starting is normal.  I've had the battery tested, as well as the starting and charging systems, at an Autozone (where I purchased the battery) and nothing has been found.  I know those systems are not the best diagnostic tools, but I haven't had time to get it to a shop.  I suspect the battery since the voltage most times I've checked is around 12.63vdc which is typically low.  Looking for anything else I can check before going to a shop and have them tell me it's the battery.


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telcoman
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Re: Intermittent battery light on

Postby telcoman » Mon Jan 21, 2019 5:15 am

tjrob2000 wrote:
Sun Jan 20, 2019 10:32 am
2007 G35 Journey sedan.  A few months ago the battery light came on and when I put a voltmeter on the battery with the car running it was at 11.9vdc so I suspected the alternator since I had recently replaced the battery.  Got an alternator from a local rebuilder/reseller in San Antonio (a new Hitachi part, not rebuilt) and installed it and all was well for awhile.  After about 3 months or so the battery light came on again with the same voltage reading.  Thinking I got a faulty alternator I removed it and took it back to the vendor.  They tested it and it looked fine with current up to 160A.  I got to see them test it so no faking it.  Put it back in and all was well, or so I thought.  IIRC the voltage was in the 13.5 - 14vdc range.  This was somewhere in the september timeframe.  Since then the light has been coming on anywhere from every few weeks to a few days.  It goes out after a few minutes of driving and starting is normal.  I've had the battery tested, as well as the starting and charging systems, at an Autozone (where I purchased the battery) and nothing has been found.  I know those systems are not the best diagnostic tools, but I haven't had time to get it to a shop.  I suspect the battery since the voltage most times I've checked is around 12.63vdc which is typically low.  Looking for anything else I can check before going to a shop and have them tell me it's the battery.
I'm on my third Infiniti and have purchased two batteries on my previous vehicles from the dealer. I've found that dealer prices on batteries are roughly twenty dollars higher than independent shops but they wash and vacuum your vehicle and everything works when you leave.
It is possible you have a defective battery? Use a battery hydrometer to test the individual battery cells

Telcoman

tjrob2000
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Update

Postby tjrob2000 » Mon Jan 28, 2019 10:40 am

Got some time to do a little further checking and found there is a 1A current draw with everything off. Some research suggests the "normal" draw shouldn't be more than 85mA. Guess the next item is unplugging things to see where the draw is.

tjrob2000
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Re: Intermittent battery light on

Postby tjrob2000 » Tue Jan 29, 2019 10:20 am

So, I made a small mistake in my initial troubleshooting.  I had a door open and therefore the interior lights were on which is why I was seeing a 1A draw.  Took care of that issue, but I still have a 147mA draw until I remove the room light fuse then it drops to 80 - 87mA.  I'll have to look through the wiring diagrams (Haynes manual, FSM's don't have this) to see what the culprit might be.  For now I'll just go without the interior lights.  Still, 147mA doesn't seem high enough to drop the battery voltage that much unless over a period of several days.

tjrob2000
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Re: Intermittent battery light on

Postby tjrob2000 » Sat Oct 12, 2019 3:50 am

So this problem went away for several months then yesterday evening the light came on and stayed on all the way home (39 miles). It was fine in the morning when outside temp was about 70 or so, but no good once temps dropped to 50's? I am thinking the battery and a test I think that will prove it is to hook up to the battery on my other car and start it and if the battery light is not on and alternator output is good then it's the battery. I'm not 100% on this, but it makes some sense to me.

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Update: anyone know what this part is?

Postby tjrob2000 » Mon Oct 14, 2019 11:18 am

To continue this saga, I charged the battery and still have the light and low output. Removed the battery and alternator (alternator is 14 mos. old, battery ~18 months) and had both tested at a local NAPA. Both test good. While there I got a negative cable since mine wasn't as tight as it needed to be (yet was as tight as I could get it, perhaps it's the whole problem). Anyway, the old cable is routed through what looks like it might be a current detector (Go to the link below to see the pic). I had to cut the old cable to get it out as neither connection end would go through and, of course, the new cable won't fit through either! Grrr…. So, what I need to know is does the negative cable have to be routed through this device? Tom

https://i1172.photobucket.com/albums/r5 ... 122026.jpg

tjrob2000
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Re: Intermittent battery light on

Postby tjrob2000 » Fri Nov 01, 2019 11:43 am

Well just when I thought this problem was gone it rears its ugly head. Ended up driving most of the way to work with the battery light on when the car started slowing so I prepared to hopefully get it off the freeway into a shopping center parking lot. Put it in neutral so I could coast longer and when the engine revved slightly the battery light blinked. Revved it to about 7k rpm and it went out and I was able to drive it the remaining 3 miles to work. I rechecked the ground cable and found I could move it on the post. Tried tightening it and can still move it. I'll check later for a different post connection for the ground cable in case I got the wrong size, but still wonder about the alternator (even though it tests good every time, but once) and the IPDM. Anyone know a good check of the IPDM? I don't have the FSM's here at work.

Tom

tjrob2000
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Re: Intermittent battery light on

Postby tjrob2000 » Wed Nov 06, 2019 9:02 am

Update. I started the car Monday to move it and the battery light stayed on. Checked output and it was 11.7vdc again. Took it to our local shop yesterday and while at a light on the way I revved it to redline and the light went off. Output is 14.3vdc constantly now. They could not get it to fail. Thinking of taking it to a shop in San Antonio that's owned by a former Infiniti mechanic. Perhaps they have some other diagnostic equipment our local guys don't have. Trying not to just throw money at it. Getting frustrating.

tjrob2000
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Re: Intermittent battery light on

Postby tjrob2000 » Thu Nov 07, 2019 2:51 pm

So, two independent shops (one owned by a former Infiniti mechanic) have found nothing wrong. Alternator is charging at this time. Maybe time to talk to a dealer? Hmmmm.......

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Re: Intermittent battery light on

Postby tjrob2000 » Mon Nov 18, 2019 9:10 am

Thought I'd update with a couple more symptoms. One, when the battery light is on (alt. not charging) the brake light is on as well. Also, I've noticed more often the drivability from a stop is not as good as it should be. It's like it loses the idle air volume learning. Overall performance is still fine, but off the line it has the hesitation like it needs to be re-learned.

It's hit or miss if the light will go out immediately after start or if it will come on sometime while driving. If it is on it pretty much always goes off if I rev the engine high, often to redline, then it stays off. As I recall (I should've done like I do at work and written things down in a log of sorts) this started shortly after replacing the battery, but the battery tests fine every time.

tjrob2000
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Re: Intermittent battery light on

Postby tjrob2000 » Tue Nov 19, 2019 7:04 pm

Took the car to the dealer for diagnosis. Also asked them to diagnose an exhaust leak. Verdict is the current sensor is faulty. The alternator connector locking tab is also broken (Which I knew since it broke on me) and they wanted $843 to replace the sensor and connector. Sensor price from them I know is $106, so the connector is another $40 and then 4 hours labor. Ridiculous. I stopped them there and told them I'll pick it up and get the parts. I get to the dealer and the report also lists the alternator for some reason, even though their testing (from the printout I got) showed it to be fine. They wanted $2189 dollars to fix that! Then, the cat would be another $1736! Way too much. So, I've ordered the sensor for $47 from a dealer online and will get the cat later on, which is $608 dollars from the online dealer ($1317 from the local dealer). This is why I rarely take my cars to shops, especially dealers. Anyway, I'll have the sensor in a few days and will install it and see if that is really the fix.

They also noted the heater coolant hoses needing replacing. I can't find them in the parts online so may have to order them from the dealer. We'll see. I'm not sure how difficult a job they are to do so may have a shop do that.

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Re: Intermittent battery light on

Postby tjrob2000 » Fri Nov 29, 2019 1:19 pm

Update: Installed a new current sensor and first start battery light stayed on and would not go off with revving the engine. Reinstalled original sensor and battery light stayed on, but went off
after revving the engine.
To recap: problem started a couple of months after purchasing a new battery. Alternator was just over 2 years old at that time. Replaced alternator since there was no output when battery light was on so figured it had failed (replacement was a new Hitachi oem unit). Problem disappeared for a month then returned. Alternator was tested at place of purchase (electrical part rebuilder) and showed good. I got to see it tested. Reinstalled alt. and all was good for a bit. It is more frequent now, but I can always get it to start outputting by revving the engine (apparently getting the alt to self-excite). Been to 2 shops and a dealer. No good diagnosis to this point. Any other ideas I'd love to hear them. So far it's been crickets mostly.

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Re: Intermittent battery light on

Postby audtatious » Sun Dec 01, 2019 11:01 am

Sorry you are having all these issues and appreciate you actively updating this thread.

Infiniti adds a bit of nannyism to the system as the Battery current sensor looks for voltage changes at the battery and communicates to the ECM. The ECM then communicates to the IPDM E/R (the box next to the battery with fuses and relays) which then talks to the IC regulator in the alternator to set voltage values. Since nobody has been able to pinpoint the issue, and the battery/alternator may not be bad, then I would suggest going through the chg.pdf FSM and test each of the 3 other systems (current sensor, ECM, IDPM E/R) to see if you can further pinpoint it. Most of this testing starts at CHG-18.

tjrob2000
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Re: Intermittent battery light on

Postby tjrob2000 » Sun Dec 01, 2019 11:15 am

Thanks for the reply. I've been through the fam and took it to a dealer figuring they would go through all that. I also figured they would be better suited to send control signals to vary the output. So far all are coming up empty.

tjrob2000
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Re: Intermittent battery light on

Postby tjrob2000 » Sun Mar 01, 2020 11:19 am

Reviving the thread with an update. Had to have the car towed home the other day after the battery light simply would not go off and it died. I put the battery on my battery minder for a couple of days and battery voltage was now 13.2vdc, higher than it's ever been. Normally it's only gone to 12.67 or so. Started the car and battery light on. Checked alternator output and it is 12.21vdc, also higher than it's been. To make sure my meter wasn't misleading me I checked the battery on my other car and it is actually low at 12.1. Guess that one needs to go on the minder! Anyway, thought I'd try something to bypass the ECM/IPDM control and disconnected the control signal to the alternator. No change. Reconnected the control signal. I went back through bank records (I unfortunately don't have the habit of tracking when problems start, something to change on my part, but I digress) and I bought a battery in April 2018 then due to this issue starting I bought an alternator, after which the problem went away for some time before coming back. I've probably mentioned this before so if I'm repeating myself, sorry, but I think it's time to try a new battery.

Connections have been checked. Fuses checked. Alternator always tests good. Battery also tests good, but I can't help but wonder if it can still have a problem that isn't detectable with normal testing tools.

Tom

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Re: Intermittent battery light on

Postby tjrob2000 » Sun Mar 01, 2020 4:24 pm

Ok, battery didn't fix it. At least they swapped it so no cost attempt. Back to the drawing board.

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Re: Intermittent battery light on

Postby tjrob2000 » Sat Apr 25, 2020 3:17 pm

Update: after the battery swap I took the alternator to have it tested and it still tested good. Before reinstalling it I cleaned the hot lead (had been cleaned before, but what the hay) and sprayed contact cleaner in the control connector (I forget the actual name). Light hasn't been on since and that is now going on 7 weeks. Will keep monitoring and if it comes back....

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Re: Intermittent battery light on

Postby audtatious » Thu May 07, 2020 8:29 am

Good find. Hopefully that was the solution.

tjrob2000
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Re: Intermittent battery light on

Postby tjrob2000 » Sat May 16, 2020 11:11 am

audtatious wrote:
Thu May 07, 2020 8:29 am
Good find. Hopefully that was the solution.
Looking good so far.


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