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Low Volts -Battery Current Sensor / IPDM

ChesbayQX56

New member
15
0
0
The volts on my 2013 QX56 have been fluctuating recently. The volts spike up to normal range when the car is started. After driving for a few minutes or sitting idle the volts average around 12.3 -12.1. If I turn the headlights on the volts go back up to the normal range. (I have been driving with the lights on) The battery is 6 months old and I have had it tested. I am thinking it is either the battery current sensor, relay, alternator, grounding, battery or an issue with the IDPM. I am going to replace the battery and shield the current sensor. If this doesn't work I am going to remove the wire between the IPDM & the alternator. This should provide me with full time alternator volts.

Has anyone had this issue? Lots of talk about similar issues on other infiniti models.

Steven
 

marctronixx

Staff member
1,290
21
38
Los Angeles
have you had the entire charging system checked?

its been discussed nissan installs these cars with less than ideal charging systems.

some people have indeed swapped out the alternator. the factory battery is one of the first thigns I personally would replace.

the grounding straps are also next on the list of mods to do. they could be better.

i dont notice "spikes" or needle jumping. i HAVE seen the needle move when under a load (switching on lamps for example) but its not "spiking" or jumping around. it moves up to just over 13 volts and settles as needed.

but for sure before you go chasing your tail. have the electrical system checked out.

could be an issue in any of those components you have listed, sure. if you have a code reader, piong the obd port and see if you get anything back...
 

mambro

New member
18
0
0
McKinney, TX
I have a 2012 QX56 and also noticed the needle movement. I had Infiniti inform me on a courtesy check that my battery (non-original / aftermarket) was failing the battery test. I bought an inexpensive digital volt meter that plugs into the cigarette adapter. It showed the same thing as you describe. I also noticed the needle/volts INCREASE as I took my foot off the accelerator from highway speeds. Why is that? The "Variable Voltage Control System". It's the Infiniti smarts to gain higher MPG by computer controlling the charging system and... you guessed it... enabling/disabling the charging as the system thinks you need it.

Here is one reference:
http://www.nissantechnicianinfo.mobi/htmlversions/2016_Feb_March_Issue_6/VoltageControl.html

BMW (and others) do similar things. I'm not a fan.

In my case, I believe the "VVCS" ruined my hefty AGM battery. Luckily, had full replacement on that, so had it swapped out at no cost. Next up, ask my Service Adviser what can be done about it. Short story: have a tech pull a pin (vs. cut wire) in the system so that the "VVCS" thinks it needs to be charging. It was a base labor charge. I was warned it would affect the MPG, but went for it.
 

ChesbayQX56

New member
15
0
0
I fixed the low volts issue! As most have mentioned in other posts, the alternator is not producing power 100% of the time. It turns off, on and some times at a lower voltage that what is recommended around 14v. The battery never fully charges, which leads to a dead battery and why they need to be replaced every 2 years. I had my electrical system checked and I was told that I needed a new alternator. I am glad I didn't listen to this fool and did some research. I have tried multiple tactics and I could never get the volts on the truck above 13v. The battery was only charging to about 12.5 volts or 50% because the alternator was not producing enough volts. I checked out this video https://www.youtube.com/watch?v=P9C5-OkxrJU and then I downloaded the charging manual and IPDM / ECU information. I disconnected the wire that goes from the alternator to the IPDM. It took me about 20 minutes and it is a lot easier than the video. My volts are a steady 14-14.5v at all times and my battery is staying fully charged at 12.7 volts. Highly recommend this procedure if you are having similar issues. 2013 QX56
______________________________
 

Beshoner

New member
1
0
0
Kansas City
I fixed the low volts issue! As most have mentioned in other posts, the alternator is not producing power 100% of the time. It turns off, on and some times at a lower voltage that what is recommended around 14v. The battery never fully charges, which leads to a dead battery and why they need to be replaced every 2 years. I had my electrical system checked and I was told that I needed a new alternator. I am glad I didn't listen to this fool and did some research. I have tried multiple tactics and I could never get the volts on the truck above 13v. The battery was only charging to about 12.5 volts or 50% because the alternator was not producing enough volts. I checked out this video https://www.youtube.com/watch?v=P9C5-OkxrJU and then I downloaded the charging manual and IPDM / ECU information. I disconnected the wire that goes from the alternator to the IPDM. It took me about 20 minutes and it is a lot easier than the video. My volts are a steady 14-14.5v at all times and my battery is staying fully charged at 12.7 volts. Highly recommend this procedure if you are having similar issues. 2013 QX56
I’m having similar issues with a 2011 Q x56. I attempted to disconnect the connection to the ECM I believe I found the wire but I wasn’t able to get the wire out. I ended up disconnecting the connector at the current sensor hooked to the negative battery terminal. Do you think this causes any issues?. It seems to be charging now at 13 to 14 V when idle. Which is what I wanted. But not sure if that current sensor is used for other things. Would you happen to have any information on where the IPDM wire is on the 2011 Q x56 and or any information on exactly how to disconnect the wire. Could I just cut it? Thanks for any help.
 

jrm5f2

Member
82
2
8
Wow! Glad I am not the only one with this problem... Thank you because I was about to replace my alternator. My voltmeter gauge was going up and down as described and I didn't know what was going on with it. I hooked up a scan tool and noticed that the volts were fluctuating depending on driving conditions. So the article you posted explained a lot, thanks.
 
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