car wont go into drive or reverse. Starts fine

[Bombastinator2]

Troubleshooting for me starts with most common, easiest (quickest) and then goes down. The easy quick free one for me is hold the brake pedal down and hit the button again. If that doesn’t work, you go on to more and more estoric and expensive stuff till it does work.

 

[cornbinder89]

. But this system voltage can be instantly pulled below the low voltage cutoff of the power supplies inside ECUs, or release relays or main contactors when something loads it, such as the brake pedal is pressed and the big capacitor bank for the master cylinder is recharged, or the blower fan is turned up to High, high beams turned on, etc.

Show me documentation of low voltage cut off points "inside the ECU, and what they are!
We have this thread, nope tried a battery didn't solve it
We have the thread at the airport, Nope wasn't the 12 volt, towed to dealer awaiting results
We have the other similar thread where the dealer found a high voltage isolation problem, they are awaiting breakdown of the battery pack, again not the 12 volt
three recent threads all have been advised to change the 12 volt, none have been fixed by doing so.
So far not a good track record.

I hear a lot of guessing and not much in the way of fact and documentation.
You consider the battery "suspect" because the person is a new member? Give me a break! No data driven indication. Car has sat for a week? We had two people come on stating theirs had sat for several weeks. You are guessing, not diagnosing, and pass off guess with BS reasoning without documentation to back it up.
ECM on ICE cars continue to function down to the point the battery is so low it can't fire the plugs or keep the fuel pressure up, but a Leaf is going shut down if it drops below 12.5? Show me documentation from the manual that states that!

 

[cornbinder89]

Troubleshooting for me starts with most common, easiest (quickest) and then goes down. The easy quick free one for me is hold the brake pedal down and hit the button again. If that doesn’t work, you go on to more and more estoric and expensive stuff till it does work.

Thats fine, if you are testing, and not just replacing things and hoping. Nothing wrong with trying to start it again, recording and then clearing code to see if the come back and under what conditions if they do. That is diagnosing, but if you mean, I'll try this part, and if that doesn't fix it I'll try the next cheapest part, that is guessing, and unlikely to be effective either in costs nor time spent on the problem.

 

[knightmb]

Show me documentation of low voltage cut off points "inside the ECU, and what they are!
We have this thread, nope tried a battery didn't solve it
We have the thread at the airport, Nope wasn't the 12 volt, towed to dealer awaiting results
We have the other similar thread where the dealer found a high voltage isolation problem, they are awaiting breakdown of the battery pack, again not the 12 volt
three recent threads all have been advised to change the 12 volt, none have been fixed by doing so.
So far not a good track record.

I hear a lot of guessing and not much in the way of fact and documentation.
You consider the battery "suspect" because the person is a new member? Give me a break! No data driven indication. Car has sat for a week? We had two people come on stating theirs had sat for several weeks. You are guessing, not diagnosing, and pass off guess with BS reasoning without documentation to back it up.
ECM on ICE cars continue to function down to the point the battery is so low it can't fire the plugs or keep the fuel pressure up, but a Leaf is going shut down if it drops below 12.5? Show me documentation from the manual that states that!

You mentioned in another topic to trust you because you were an engineer. You never said of what so we kind of assumed at least electronics? The circuit diagram shows that 12V is required to power it. It's not a suggestion, it's 12V for a very good reason. What happens if you only power the circuit with 9V or 8V or less? You don't need to know the exact specs of the devices to know that anything below 12V is going to cause issues. This can happen with a weak 12V battery, it drops voltage across the whole system. I did experiments some years back where I measured how much power it takes to start a Leaf. It's not a lot, but if a 12V battery can't handle +150 watts for a few seconds plus whatever else is running at that time and the voltage drops so fast, what do you expect the other systems to do trying to start up with less than design spec voltage?

Maybe you are right though, we need better documentation? I go through enough dead Leaf batteries that probably sometime in the future I can setup an experiment to show in real-time what happens when you try to start a Leaf on a weak battery, the dash response, the LeafSpy codes, multi-meter readings of the battery and then follow it up with a load test and a capacity test of said bad 12V battery. I can see that it would certainly be useful to help with these type of discussions in the future.

 

[Bombastinator2]

Show me documentation of low voltage cut off points "inside the ECU, and what they are!
We have this thread, nope tried a battery didn't solve it
We have the thread at the airport, Nope wasn't the 12 volt, towed to dealer awaiting results
We have the other similar thread where the dealer found a high voltage isolation problem, they are awaiting breakdown of the battery pack, again not the 12 volt
three recent threads all have been advised to change the 12 volt, none have been fixed by doing so.
So far not a good track record.

I hear a lot of guessing and not much in the way of fact and documentation.
You consider the battery "suspect" because the person is a new member? Give me a break! No data driven indication. Car has sat for a week? We had two people come on stating theirs had sat for several weeks. You are guessing, not diagnosing, and pass off guess with BS reasoning without documentation to back it up.
ECM on ICE cars continue to function down to the point the battery is so low it can't fire the plugs or keep the fuel pressure up, but a Leaf is going shut down if it drops below 12.5? Show me documentation from the manual that states that!

I’m taking this as implying that the minimum is 12v. There seems to be a lot of disagreement about what the minimum level of that battery needs to be. So far I’ve seen something below 11, 12, and something below 13.

 

[cornbinder89]

You mentioned in another topic to trust you because you were an engineer. You never said of what so we kind of assumed at least electronics? The circuit diagram shows that 12V is required to power it. It's not a suggestion, it's 12V for a very good reason. What happens if you only power the circuit with 9V or 8V or less? You don't need to know the exact specs of the devices to know that anything below 12V is going to cause issues. This can happen with a weak 12V battery, it drops voltage across the whole system. I did experiments some years back where I measured how much power it takes to start a Leaf. It's not a lot, but if a 12V battery can't handle +150 watts for a few seconds plus whatever else is running at that time and the voltage drops so fast, what do you expect the other systems to do trying to start up with less than design spec voltage?

Maybe you are right though, we need better documentation? I go through enough dead Leaf batteries that probably sometime in the future I can setup an experiment to show in real-time what happens when you try to start a Leaf on a weak battery, the dash response, the LeafSpy codes, multi-meter readings of the battery and then follow it up with a load test and a capacity test of said bad 12V battery. I can see that it would certainly be useful to help with these type of discussions in the future.

That wasn't me who said they were an engineer, I remember the statement but not the thread or who said it.
Fact remains in the last few weeks we had several cars with problems that the O.P. was told to change the 12 volt battery and it didn't fix or change the problem. It is not helpful to spend other peoples money on a guess.
Contactor coils draw more to pull in than to hold in.
If you are going to make recommendations that the battery is a fault, you should know at what voltage it will cause a symptom and what that symptom will be.
And hey, guess what? when the system is turned on, the DC to DC converter is active! It doesn't need an engine to start turning before it supplies power.
I'd much rather see people who want to fix their own, or at least do some basic diagnosing, to put that battery money toward a code reader and/or a good voltmeter, that is a better use of that money. 3 threads and 3 fails is not a good argument for a new battery.

 

[Stanton]

I did experiments some years back where I measured how much power it takes to start a Leaf. It's not a lot, but if a 12V battery can't handle +150 watts for a few seconds plus whatever else is running at that time and the voltage drops so fast, what do you expect the other systems to do trying to start up with less than design spec voltage?

I remember those tests @knightmb, so here's some perspective (I realize you know this).
There is voltage and there is current. You may have a starter battery measure 12v, but if it can't deliver any current (ultimately power), it doesn't matter what the voltage is; similarly, if you're not seeing something close to 12v (and this has been argued in hundreds of posts across hundreds of threads), it doesn't matter what Amps the battery is rated at--the car won't "start".
When I was choosing what type of Lithium battery to replace the original lead-acid battery in my Leaf with, I knew that a Leaf doesn't require the "cranking power" of an ICE vehicle, so I went for a much smaller (both in size and power) 12v replacement. To reliably start my Leaf required something >10 AHrs and really closer to 15 AHrs. Based on what was available, I ended up with a 12v @20 AHr Lithium replacement...which actually has a "resting voltage" closer to 13v with a decent charge (another reason Lithium is better for EVs--but that's for another discussion). I'm still using that same 12v LiFePO4 starter battery after 10 years!

 

[knightmb]

That wasn't me who said they were an engineer, I remember the statement but not the thread or who said it.

My apologies, I got mixed up, so ignore my snarky reply.

 

[knightmb]

As luck would have it (or not), I just got a 2018 Leaf where my relative was unable to start it this morning. I went over to check with LeafSpy and here are the codes. Look familiar? Also, make note of the battery voltage with only a 24 watt load which is me with just the dash on, no accessories like fans lights, heaters, etc. I suspect the 12V battery, but I'm going to check first if it really has an isolation issue with the case. If I find no issues, then I'm going to suspect the 12V battery. I'll start another topic just for this so as not to clog up this one so much.

 

[cornbinder89]

Quick and dirty, clear the code and see if it returns before doing anything else. If it does, any other diagnoses is going to be a waste of time. If HV is leaking to the 12 volt side of the DC-DC converter (in other words ground), it can't be assumed it can charge the 12 volt.
Two things were done to my Leaf by the previous owner, brakes, and a 12 volt battery. Found the date code on the replacement, it was installed late 2022, on the 2015 vehicle, That is a minimum of 7 years on the original.
Found the date code for the gp 51 in my tractor, 1st month of 2018, so 6 years on that one and it is still going strong.
I would charge the 12 volt before condemning it, it may be just discharged, or it may be bad, but you can't condemn on voltage without knowing if it has been charging or not.
If the "key" was on, the Dc to DC should be on, but would look like it is not, so more reason to charge, clear and see if it returns. That is what happened in the one that is now sitting in the dealership waiting for the HV battery to be removed.
Just to make sure, I wasn't mis reading the manual. I went out to my Leaf, put a voltmeter on the battery, and turned on the "key", and the DC-DC came on with the key and voltage jumped to 14.5, then settled to float after a few minutes, just as the manual said it should.

 

[Bombastinator2]

I take it the “be sure the brake is held to the floor” thing didn’t work?

 

[Webnine]

Ended up having car towed to Nissan dealer and it was corrosion on the heater harness. Very expensive repair on top of battery I purchased thinking maybe that was the problem.

 

[Bombastinator2]

Ended up having car towed to Nissan dealer and it was corrosion on the heater harness. Very expensive repair on top of battery I purchased thinking maybe that was the problem.

Ouch. Yeah. Wouldn’t have caught that one both deep and unusual. Corrosion happens because things get wet (or sit out in the air for a really really long time) wet is the only one in the time frame though. Finding out how it got wet in the first place seems aprpos

 

[Webnine]

I keep car in garage when I go to Florida. Is there a way to keep this from happening again.

 

[Webnine]

They wanted $600 to try to repair or $3600 to totally replace. Am waiting for them to call if they can repair. They said they would give me a break if it needed whole new harness

 

[cornbinder89]

Without being able to see where the problem is, it would be difficult to say what caused it or what could be done to prevent it.
Thank you very much for following up with what they found. I hope they can fix it at the cheaper price.

 

[Webnine]

Thanks, from what I read it is mainly preventative maint. such as rustproofing and occasionally taking off bottom panels to remove moisture, ect. Seems like more than I want to tackle just to own a EV. Poor engineering. My son is a thermodynamic engineer for Space X then he moved to Blue Origin where he is now and he does not think this should happen and is preventable by Nissan

 

[cornbinder89]

Proper design and understanding of what the item in question will face when in use will go a long way in preventing problems.
If you don't mind me asking, what part of the country do you live? Parts like mine, where they spray brine on the roads every time the temp comes close to freezing, can do a whole lot of damage to the wiring. It was a constant battle with the trucks and trailer when I was trucking. The brine could even get between the two layers of glass on an outside mirror and eat away the silvering in between. It eats the re-bar out of bridge decks, and they don't even put it on the trucks, the tow a light 2 axle (disposable) trailer with the brine tank and spray equipment well back from the truck!
It is very hard to make a good connector able to keep the stuff out, the lighting on trucks used "sealed connectors" and sealed lights where the bulbs were not replaceable, but still connections were the fail point. Rarely did a bulb fail esp when most were LED type bulbs.
It was New York state somewhere, wasn't it? do they brine like the do out here in Iowa?

 

[Bombastinator2]

They wanted $600 to try to repair or $3600 to totally replace. Am waiting for them to call if they can repair. They said they would give me a break if it needed whole new harness

Repair will probably involve removing the corrosion and sealing it somehow. It’s probably going to come down to how bad the corrosion is and/or whether the thing is small enough for them to fit it in whatever device they want to use to remove the corrosion. Just guessing though. With some consoles there are corrosion issues that can be fixed with nothing more than a pink pearl eraser. This isn’t a console though.

 

[Bombastinator2]

I live in Minnesota so they salt stuff too. Sometimes it’s brine. This year has been really warm though. Disconcertingly so. Warmer than Missouri. No snow. Rain, but no snow, so there hasn’t been much salting of roads. A car sold in the U.S. should have anti-corrosion stuff for such though. It’s expected. A long time ago I drove a diesel vanagon. They did corrosion protection for it with a 1/8-1/4” thick coating of wax across the entire under carriage. Real mess if you had to work on anything. The stuff was sticky. Much softer than, say, candles. Might have actually been bee’s wax. It was yellow enough.

UPDATE: it was pointed out below it was more likely cosmoline (which I associate with being al lot like thick vasoline. One used to find it on military surplus stuff a lot).

TLDNR: musing about possible preventatives

They use vasoline to waterproof motherboards for liquid cooling competitions. Doesn’t need to be long term, but I wonder if it is? (If it isn’t it would be bad) I wonder if it could be used as a field serviceable waterproofer for such things. Cosmoline undoubtedly works better but you can get vasoline at the grocery store