Nissan Charging system

John Owner/Technician Iowa Posted   Latest   Edited  
Unsolved
Electrical
2014 Nissan Murano LE 3.5L (A VQ35DE) (RE0F09B) — JN8AZ1MW9EW531852

I am trying to figure out this Nissan charging system. The shop that called me install a reman Nissan alternator for a no charge symptom with no change, it still will not charge.

I scanned the system for codes and the only code is for the sunload sensor in the HVAC module. I commanded the alternator to 50% in the ECM, still no charging. I performed a voltage drop test on the main battery cables both were under 500mv. I tested at the alternator connector, pin #4 will light a 9007 bulb, pin #3 has 12v and will light the battery light when grounded, pin #5 has continuity and will light a test light when loaded. I ran a ground to the alternator from the battery with a jumper cable. The connector for the alternator is new.

The IPDM was replaced with a used one, the battery negative cable and the current sensor are new from Nissan. The can signal at the IPDM pins 39 &40 are good. 

I cut the wire at pin #76 at the IPDM with no change. If I use the signal generator on my Autel MS919 and put a 6v peak to peak square wave at 50% duty cycle on the control circuit the alternator will charge at 13.5V.

I went on a 10 mile test drive and the ECM never tried to command the alternator to charge. 

I suspect that the ECM is bad but at $2000 I want to be sure.

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Louie Technician
New York
Louie
 

The ECM on most Nissans commands the alternator to charge on deceleration in order to save fuel​.​verify this while driving with a voltmeter or scanner .There is a specific fault code that sets whenever the alternator isn’t charging.

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John Owner/Technician
Iowa
John
 

No codes were set. When i got back from my test drive I had to jump start it to get it started again.

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Jeff Owner/Technician
Arizona
Jeff
 

I do not have a solution for you. However, I have had this exact same scenario on three different Nissan vehicles - a 2014 Altima, a 2009 Murano and a 2011 Frontier - and all were fixed on their 4th or 5th alternator. I believe all of the above vehicles have essentially the same charging system.

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John Owner/Technician
Iowa
John
 

It's on it's 3RD. I can make the system charge by applying a signal to the control circuit.

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Jeff Owner/Technician
Arizona
Jeff
   

As could I. I went through the same contortions as you have and pulled the trigger on a new IPDM on the first one. I bailed after that. I spent most of a day on that Altima because it belonged to a friend. After I gave up, he just threw alternators at it until he got a unit (for $800) from Nissan. I suspect the field wire from the IPDM senses something.

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Alex Diagnostician
Australia
Alex
 

No command from PCM. Did u scope signal wire @ alt and at PCM ... no signal evident??

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John Owner/Technician
Iowa
John
 

It communicates with the IPDM over the CAN network, The IPDM controls the alternator.

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Alex Diagnostician
Australia
Alex
 

Absolutely certain there is no pin fitment issue at the harness plug? Long shot, I know

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John Owner/Technician
Iowa
John
 

The connector for the alternator is new.

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Paul Mechanic
Illinois
Paul
 

Is it wired correctly? Had one come from a dealership that was at pepboys that change alternator first, then changed connector then changed alternator again then went to dealership that wanted to sell customer another alternator. Towed it to me and I had found connector wired wrong. Suspect first alternator was bad, but since it didn't fix it, cut in new connector(incorrectly) second alternator…

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Mihail Technician
Maryland
Mihail
 

May be the used IPDM is not generating a signal even though on the communication side of it all looks good. I don’t know if that would set a code but kind of doubt it. You can ask the shop why the IPDM was replaced and if they say they had one and just wanted to try it then ask if they still have the old IPDM and put it back on. It is also possible that the IPDM is ok but does not like the…

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John Owner/Technician
Iowa
John
 

I checked the harness myself, It looks right.

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Paul Mechanic
Illinois
Paul
 

Not much experience with Nissan charging systems, but I've had plenty of the Ford one and usually you get a p06xx code along with the cel, battery lamp lit and check charging system message and it defaults to 13.5 volts. Does the duty cycle change or command start at one level when you first start engine then seem to default to what ever your seeing? Comparing it to how the Ford's work when pcm…

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Jeff Owner/Technician
Arizona
Jeff
   

The alternator isn't controlled directly by the PCM in this application.

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Michael Technician
Indiana
Michael
 

Jeff, I thought this was interesting. The SI states that when there is not a signal sent to the alternator, It defaults to it's internal regulator. My understanding being that if there is a fault in the control of the alternator it should still default to the IC regulator. I had a blower motor that wouldn't work, Didn't have control signal from the Climate control. The problem was the…

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Jeff Owner/Technician
Arizona
Jeff
 

In a normal world, this is the way I would have expected alternator to work - a default strategy. What the original poster is experiencing is that the control signal which comes from the IPDM is an open circuit - not a ground and not a power signal. What the alternator that's in the car is expecting (according to his experimentation) is a 50% duty cycle 6 volt square wave that stimulates it…

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John Owner/Technician
Iowa
John
 

I am going to have the shop try another alternator, this will be #4 and I will post the results

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Michael Technician
Indiana
Michael
 

I knew I didn't explain it well enough. Question, is the signal (the square wave) From the IPDM a Pull - up , or a pull - down. In my example, The Climate control had a pull down Square Wave. The voltage being pulled down was from the variable fan speed controller. So, if pin 5 from the alternator is supossed to have 12 volts and the IPDM sends a pull dpwn duty cycle, you would never see…

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Jeff Owner/Technician
Arizona
Jeff
 

I understand your point. The problem is, there's nothing being sent to the alternator. It is effectively an open wire. It is neither pulling up nor pulling down the alternator.

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Daniel Engineer
Virginia
Daniel
 

Unplug the battery sensor on the ground wire and see what voltage are you getting. Nissan is notorious for having faulty battery current sensors that fools the ecu and have techs changing the alternator. If its to 13.8V and up, change the current sensor

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John Owner/Technician
Iowa
John
 

The battery cable and the current sensor are new

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Alex Diagnostician
Australia
Alex
 

John I'm feeling the pain. This one is frustrating. However, you're about to pull the trigger on the ECU, but I'm not seeing clear evidence that the ECU is not issuing a command (Is there an Actual vs Desired V PID by any chance??). On balance, i'm leaning to the IPDM not delivering the mail, even though it has been replaced … you consistently have no signal on Pin 5 unless you create your own…

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Thomas Owner/Technician
Texas
Thomas
 

You still have pins 51, 44, and 42 at the ECM from the current sensor. Are they good? Also remember N.E.W. means never ever worked.

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Louie Technician
New York
Louie
 

Is the 10 amp mini fuse for the alternator good?it’s in the fuse box under the hood next to the pull the fuse and check for burns on the legs swap it out even if it’s not blown

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Shane Technician
Massachusetts
Shane
 

It's a long shot but I would recheck pin fitment at pin 76 at ipdm. I have found loose pins at ipdm in Nissan for various things.

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Timothy Owner/Technician
Wisconsin
Timothy
 

No light when the alt. is plugged in, KOEO, means you've eoither got the wrong alternator, or the regulator in it is bad. The regulator's job is to ground the circuit when the alt is not turning, and turn the light out when the alt is turning. No light activation means bad alternator, regardless of the number of units replaced.

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Jeff Owner/Technician
Arizona
Jeff
 

And, as an additional data point in that side of the discussion, a number of years back I noticed that most of the parts houses had consolidated multiple Nissan part numbers into single numbers. That was okay as long as you are on the newer side of a revision. However, it meant for some older models you absolutely had to get the correct part number from the dealer because the aftermarket…

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Lazer Mobile Technician
New Jersey
Lazer
 

I had a similar problem on a 2019 Murano, ironically it was a much simpler system then this. the battery light never came on with koeo and the voltage was all over the place. The shop tried 2 aftermarkets that didn't help. They got junkyard OEM and it fixed it.

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John Owner/Technician
Iowa
John
 

The alternator on it now is a Nissan pn 23100-1aa1b. I do not know where it was sourced from, I recomended to order one from the Nissan dealer by the vin.

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Jeff Owner/Technician
Arizona
Jeff
 

So, as you can see, we run into problems immediately. That part number is good up to 2014 according to Nissan's website. So you're good there. However, if you look at O'Reilly for instance, that alternator suddenly becomes the correct alternator again for 2017 and up, even though they're wired completely differently. They do, however, have the same plug.

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John Owner/Technician
Iowa
John
 

It just seems like a crap shoot anymore to get a good part.

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Jeff Owner/Technician
Arizona
Jeff
 

You're not kidding. I started tidying up my bookkeeping for 2021 so I can get ready for my tax filing and I'm realizing that an enormous number of my stops were advising customers to replace parts that they had already replaced. Alternators we're at the absolute top of that list, followed by starters at a distant second. (To be fair, aftermarket Ford alternators were the lion's share of that…

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John Owner/Technician
Iowa
John
 

I would track it but honestly these are the ones you want to forget

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Jeff Owner/Technician
Arizona
Jeff
 

Additionally, even though your VIN decodes to a 2014 model, if the vehicle was built later than May of 2014, and may be wired as a 2015. The plug is also compatible, but wired yet a different way. The field wire on the IPDM moves in 2015, so I presume you're good there as shown by your experimentation. It's just another thing to be aware of.

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Saul Diagnostician
Texas
Saul
 

Agree with Timothy. This is the way I have seen Nissan alternators behave. The regulator should ground the circuit with KOEO.

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Michael Technician
Indiana
Michael
 

John, This will be my last post and I won't bother you anymore. 1)The Alternator outputs 6 volts on the sky blue wire once it is excited. 2) When the ECM wants to lower the charge level, It will begin to pull the 6 volts to ground repeatedly forming the square wave. 3) The Brown wire is the ground side of the charge light in the combination meter. The Brown wire is the field excitation…

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Timothy Owner/Technician
Wisconsin
Timothy
 

Great explanation! I believe he's overthinking this a bit. Seems fairly straightforward…

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Jeff Owner/Technician
Arizona
Jeff
 

What seems straightforward about “let's replace the alternator for the 4th time”? It's perfectly normal to “overthink it” when you find yourself doing the same thing over and over again. Einstein said “the definition of insanity is doing the same thing over and over again and expecting a different result”, or something to that effect.

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Timothy Owner/Technician
Wisconsin
Timothy
 

LOL! I guess, from that slightly skewed perspective it may not seem straightforward. But, it's basically the first test I use on a system such as this. Ain't got a light when it's plugged in KOEO? The alternator is bad, once the light circuit is proven out. It's not the same (obviously) for other OEs, and maybe just other models within the same ‘house’, but, in this case, I wouldn't go further…

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John Owner/Technician
Iowa
John
 

I probably was overthinking it a bit, but when they are going on there fourth alternator you want to make sure that all of your bases are covered. I gave my recommendation to the shop, we will see how it goes. Unfortunately some times in our business you only hear about it when you are wrong

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Michael Technician
Indiana
Michael
 

You are absolutely right John. When you do a great job, you are lucky if they tell one person. When you do a lousy job, get a bad part, or just plain make a mistake (we are human after all), they will tell ten people. I wish you well with your nissan.

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James Technician
Maryland
James
 

I had an 11 Maxima drive me crazy after replacing the alternator 3 times and replacing an engine harness. Found after communicating with Nissan, the tech was over-torquing the nut on the stud for the positive cable on the alternator causing it to come loose internally, which it would then stop charging. That was a problem with Nissan alternators for a while. Was told that was common on those…

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