VStar650CL wrote: ↑

Wed May 25, 2022 7:20 pm

Just checked the FSM, the hood switch wire is Orange on pin 24 at the IPDM, just two pins up from the Brown alternator wire on 22.

I will check the orange pin 24 tomorrow. Thank you.

denbigh97 wrote: ↑

Wed May 25, 2022 8:30 pm

VStar650CL wrote: ↑

Wed May 25, 2022 7:20 pm

Just checked the FSM, the hood switch wire is Orange on pin 24 at the IPDM, just two pins up from the Brown alternator wire on 22.

I will check the orange pin 24 tomorrow. Thank you.

hopefully you unplugged the battery before you started disconnecting wires or else you might have shorted something, which is very easy to do in this car.

Yoda's Master wrote: ↑

Wed May 25, 2022 9:34 pm

denbigh97 wrote: ↑

Wed May 25, 2022 8:30 pm

I will check the orange pin 24 tomorrow. Thank you.

hopefully you unplugged the battery before you started disconnecting wires or else you might have shorted something, which is very easy to do in this car.

I did make sure to disconnect the battery before I opened the IPDM. I don't think there is enough space to even remove/open the IPDM without taking out the battery?

denbigh97 wrote: ↑

Wed May 25, 2022 10:56 pm

Yoda's Master wrote: ↑

Wed May 25, 2022 9:34 pm

hopefully you unplugged the battery before you started disconnecting wires or else you might have shorted something, which is very easy to do in this car.

I did make sure to disconnect the battery before I opened the IPDM. I don't think there is enough space to even remove/open the IPDM without taking out the battery?

ok. it's been a few years since i did the mod so I don't remember the lack of space.

Did you get it figured out?

Yoda's Master wrote: ↑

Thu May 26, 2022 8:24 pm

denbigh97 wrote: ↑

Wed May 25, 2022 10:56 pm

I did make sure to disconnect the battery before I opened the IPDM. I don't think there is enough space to even remove/open the IPDM without taking out the battery?

ok. it's been a few years since i did the mod so I don't remember the lack of space.

Did you get it figured out?

Yes, I took the car to a local garage and was told the low voltage from the old battery triggered the error code in the BCM. They were able to clear the codes in the BCM. I will pick the car up tomorrow.

After replacing my starter motor, all my battery/alternator problems magically disappeared. Turns out it wasn't the charging system at all. I think the original starter motor was weak and it drew WAY too much from the battery, so no-start was a regular occurrence. So I had to keep my battery at 100%, not 95%. But my new starter motor has way more oomph, and starts on 1st button press, no matter what. The battery charge is no longer a concern. I now trust this car.

ibc wrote: ↑

Mon Aug 08, 2022 8:25 am

After replacing my starter motor, all my battery/alternator problems magically disappeared. Turns out it wasn't the charging system at all. I think the original starter motor was weak and it drew WAY too much from the battery, so no-start was a regular occurrence. So I had to keep my battery at 100%, not 95%. But my new starter motor has way more oomph, and starts on 1st button press, no matter what. The battery charge is no longer a concern. I now trust this car.

Thanks for the update ibc, I find that really intriguing. Although I must say I'm not surprised by the outcome.
I recall that we had discussed this possibility about 2 years ago:

EdBwoy wrote: ↑

Thu Apr 23, 2020 10:26 pm

ibc wrote: ↑

Fri Apr 17, 2020 2:18 pm

Yup, sometimes I get the click-no-start too. But after few (1-3) presses, the starter eventually gets power and it always starts up strongly. Dunno why this happens. Is it related to the alternator ECM disable mod?

I am not saying that the smart alternator disable mod is the cause of the click-no-start. The issues might be related, but I am trying to find out how. I am trying to see if something in the starter circuit causes the click-no-start issue. And whether this circuit problem is what is discharging batteries.

...

My car has "Disable ECM Controlled Alternator" and my battery last 4+yrs already. Without it battery only last 2yrs.

I bought a 2019 Armada a few months ago and I've had a few no start episodes which were corrected with a jump or a charge. Am I correct in understanding that Nissan could fix this issue with a software update for the Variable Voltage Control System which would allow it to maintain a higher voltage? Then why don't they just do that??!!??!! Anyway, I'm going to disconnect/remove the Electronic Control Module (ECM), as shown in the attached picture. Many others have done this and it seems like the easiest fix. Similar to unpinning in the IPDM. My question is, is this an acceptable fix compared to unpinning? Has anyone been able to compare the fuel economy with the ECM removed vs not removed? Or unpinned vs pinned? Does it affect anything else, besides fuel economy, to remove the ECM or unpin in the IPDM? So far I've heard of no issues, except maybe a fault code. And it seems like the battery will actually stay fully charged. Thanks for any feedback!!

What you're looking at on the negative battery terminal is a Current Sensor. Calling it an ECM confuses the issue, the ECM (Engine Control Module) is the "brain" that runs the engine, and the abbreviation ECM is reserved strictly for it. You can generically call a computer in the car an ECU, but the battery current sensor isn't a computer of any sort, it's just a sensor.

Depending on the sort of driving you do, disconnecting the sensor may or may not resolve the issue, and in any case it will cause DTC codes in the BCM (Body Control Module) which monitors the sensor. There's also no need to remove it, disconnecting the 3-wire plug on it will serve the same purpose. However, disconnecting the "smart" wire to the alternator is an altogether more reliable solution which won't cause codes. There is no firmware fix for the issue, neither the BCM nor IPDM are reprogrammable due to security constraints.

Wow, thanks the info, very helpful! And sorry for the lack of knowledge. I'm learning as I go. I already disconnected the current sensor and taped it off and everything seems better so far. So I'll leave it for now I think. I'm wondering if a lack of charging because of the current sensor/ECM could have damaged the battery? When it wouldn't start, the reading was only 5.37v. After charging/jumping, resting voltage was only 11.7v before removing the current sensor, which I think seems low. After removing the current sensor, resting voltage is about 12.2v-12.4v, which I still think seems low. Is it possible the battery is still recovering or is it more likely damaged? Shouldn't resting voltage be closer to 12.6v (my older car (apparently with a current sensor connected) shows a resting voltage of 12.58v).
In reference to firmware, don't these service bulletins (NTB19-099e and NTB20-065) address the issue by reprogramming the ECM? I'm not sure if it applies to my ECM because I don't know the full part number. Is there a way to see the full part number for the ECM besides connecting a scanner/reader tool?
Thanks again, so much, for your help!!

You're most welcome. To understand the problem you need to understand that the "smart" charging system employs a chain of devices, not just the ECM. It's actually the BCM which monitors the current sensor and requests a particular charge level based on system voltage and system load. It passes that request to the ECM via the CANbus, and the ECM can veto it if there are overriding engine conditions like WOT or an overheating engine which require reducing extraneous loads. If there's no veto, the request is passed via CAN to the IPDM, which actually runs the alternator.

In practice, the ECM repro from NTB19-099 was supposed to improve the situation but didn't. That's because the BCM actually performs the load calculations, not the ECM, and the BCM isn't reprogrammable. NTB20-065 was for a completely different issue, the Armada brake switches are a well-known sore spot (along with similar issues on a lot of other Nissan models). Neither bulletin particularly addressed the underlying issue of current sensor malfunction.

To answer your first question, anytime a regular battery dips below 8V it will lose some of its plate material on recharge, so repeated episodes of deep discharge are bound to reduce its CCA (as much as 20% for really deep discharges, and your 5.37V was really deep). The only way around that, aside from not letting it happen in the first place, is to use a deep cycle battery.

Thanks again! I just got my Armada a few months ago, and I found it interesting after the first no start issue, that the service department noted a new battery had been installed right before we bought it. It makes me wonder if there were issues with the previous owner. They failed to mention anything about any service bulletins or workarounds that can help save the battery, so I'm wondering if I should view them as being responsible for it and request a new battery. I guess we'll see what they say. All they said they did so far was to "put the computer into a lower power usage mode," whatever that means.
For the service bulletins I actually meant to say NTB20-021, not NTB20-065. It addresses software in the ECM which allows the Variable Valve Timing (VVT) solenoid valve diagnosis to continue to draw current when the engine is off, which reduces battery life. But it affects the exact same ECM part numbers as NTB19-099e. Is the VVT actually controlled by the ECM? Or is it controlled by the BCM like the current sensor? Would reprogramming the ECM possibly help at all?
Also, will the ECM still monitor for conditions such as overheating engine, even with the current sensor removed?
Thanks again!!

Yah, the VVT is controlled by the ECM. That bulletin was a genuine software glitch, but only certain ECM's did it (no explanation why, but my suspicion is a production tolerance issue). If yours hasn't had the update then that could be a genuine issue. Good scanners can upload the ECM part number, cheap ones can't. If you need a cheap out, there's an app called NDS-III that uses an ELM327 bluetooth adaptor to talk to the car via the OBD port. It doesn't work on all models, but if it works for you then it has the capability to upload the p/n.

The current sensor being disconnected will only bother the BCM, the ECM won't care and won't be functionally affected.

Thank you- I really appreciate your help! I ordered an adapter to see if it works. If not, I'll have the dealer check the part number. With the current sensor removed, and any updates for the ECM, now I just need to see if the battery is still good or if I need a new one. I'll put it on the battery charger and see if the resting voltage goes up and stays up. So far it only stays at 12.4v, but it hasn't been driven a lot. That's still better than the 12-12.2v it had before removing the current sensor. Thanks again for all your help!!

12.4V is a perfectly healthy float voltage after the battery sits for awhile. 12.8V is what you generally see right after shutting down the engine, then it will gradually drop off.

Thanks! That's good to know. I wasn't sure. I thought it had to be about 12.6v for some reason. Why do some cars maintain a higher float voltage than others? Is it just the condition of the battery, or other factors? I topped off all 6 holes with distilled water this morning. Each took at least 50mL. Now it's slow charging on a battery tender. Hopefully that will help even more. Thanks again for sharing your knowledge and helping a guy in need. Much appreciated!!

Droid wrote: ↑

Thu Sep 15, 2022 8:17 am

Thanks! That's good to know. I wasn't sure. I thought it had to be about 12.6v for some reason. Why do some cars maintain a higher float voltage than others? Is it just the condition of the battery, or other factors?

There's some production variance involved with that, but the 12.6V standard is for a new battery with a tip-top charge. Anything 12.4V or above is generally healthy, but bear in mind that the battery needs to be disconnected from the car and then sit for several hours before float voltage really means anything. When the battery is connected to the car there's always a tiny amount of discharge going on (usually around 30 milliamps for an Armada) which will tend to drag down the float level as soon as the car is shut off.

Ok. Makes sense. Thanks again!!

It seems to be holding a charge better now. Thanks again. One more question. Do you have any idea what this is and is the connection supposed to look like this? Just one red wire? It's behind the grill and below the battery. Is it the horn? Just wondering if it needs to be fixed. Thanks!

....

it looks like a aftermarket horn. you should get that fixed

Interesting. The horn works. I wonder why they put an aftermarket horn in? Is just the one red wire ok? Thanks.

there are two horns. high and low tones. the other is behind the bumper, under the headlight.
the steel bar it's attached to is the ground so yes, just a red wire is normal.

Ok. Good to know. Thanks for your help!!

So I got my Bluetooth adapter and NDSIII shows it's connected to the ECM but it doesn't display anything for the ECM part number. A different app displays the ECM control ID, but that's it. Am I probably out of luck for the part number except for the dealer, or a better scanner? Thanks.

Droid wrote: ↑

Sun Sep 18, 2022 10:41 am

So I got my Bluetooth adapter and NDSIII shows it's connected to the ECM but it doesn't display anything for the ECM part number. A different app displays the ECM control ID, but that's it. Am I probably out of luck for the part number except for the dealer, or a better scanner? Thanks.

Yep. NDS-III doesn't give full functions on a lot of stuff past about '16, and it may not be able to read your '18 properly. I don't know of any other "cheap out" for getting the ECM p/n. However, it occurs to me that NTB20-021 was a recall, not a bulletin. So you should be able to run your VIN through NHTSA to see if it's an outstanding recall for your ride. If it isn't, then it was either already performed or the vehicle didn't have the faulty firmware in the first place.

Awesome. I'll check. Thanks again!!

Hello. Just wanted to provide a bit of an update. I called the dealer and the technician was not helpful because in their system it doesn't show anything about these recalls or service bulletins applying to my VIN. But I did speak to the parts department and he was able to give me my ECM part number. It starts with 23703-, not 23710-. So apparently the bulletins shouldn't apply. But interestingly, he said that right before we bought it, recall P0A05 (NTB20-021) was performed. So apparently the ECM was reprogrammed to address the VVT battery drain. So that's good I guess. Not sure why it was done if the part number didn't match the applicable recall/bulletin part numbers. The previous owner must have been having issues. He didn't know about NTB19-099e but he did say that shortly after taking in the new vehicle the ECM was reprogrammed. So maybe it was for NTB19-099e. I guess that doesn't matter because it doesn't fix the current sensor issue anyway, because it's unfixable, except for disconnecting the current sensor. It's crazy there's no real solution from Nissan for this. I wonder if there will ever be a class action lawsuit because of it. One more question I thought of, is the BCM replaceable (not reprogrammable) and would that fix the current sensor issue? Thanks.

The p/n the parts man gave you doesn't mean anything. That's the hardware part, it doesn't tell you the software p/n. I doubt there will ever be a legal action because there won't be a reason. Dealers know about it and have been covertly disconnecting the "smart wire" for some time now, usually with something like "reconfigure IPDM" submitted on the official repair order.