P0302 Cylinder Misfire

Capncorroded

Hey everyone, trying to track down a p0302 Cylinder #2 misfire

2016 Nismo with 6900 miles on it. No mods.

Battery was low, so i removed the battery to charge it. When I reinstalled and started the car up it started misfiring with the mystical p0300, but a more dedicated p0302. Doesn't make sense.

Here is what I know:
I have already been through the basics.
No visible loose/disconnect connectors
MAFs are clean
02 sensor voltages in range
Injectors are good - not a fuel issue
Plugs are all new
Coil packs are good - code does not move to another cylinder when swapped
Visually verified #2 is not sparking by removing coil pack, grounding the plug, and watching for spark. Tried same coil and plug grounded on other cylinders, and can see spark.

Cylinder #2 is def not getting signal to spark.

I started going through the diagnostic procedures in the FSM for this code. Verified 12v constant and good ground at harness for coil.
Verified continuity between ECM and signal wire on harness

One part in the FSM says to test condenser (connector f8). I was pointed by someone on facebook that its the little sensor on AC condenser, which I do not believe, it makes no sense to have an AC sensor in the ignition circuit. Also, its not even the same colors/2 wire plug the FSM shows. I do know what an electrical condenser is, but I cannot for the life of me find where this hidden to test it. It does show it in the ignition coil circuit diagram, but I would think this would affect all cylinders, but I may be wrong.

Short of the tests done with Nissan Consult which I don't have- majority of the FSM procedures test ok, except for the things I can't physically locate.

The car still has warranty, and I know it will be covered, but the closest *good* dealer is quite a hike, and we still have a bunch of snow in my area. I would like to avoid a tow to the dealer if possible if its something stupid I may be missing. Its more of a pride thing now, and I just want to figure this out because warranties don't last forever.

Anyone have experience with this?

SouthArk370Z

How many miles have you driven since you restored power? When power to the ECM is removed, it loses all the run-time parameters and resets to defaults. It takes a while for the ECM to relearn the params. Take it for a 15 minute drive, under varying conditions, and see if things improve.

Edit: " I do know what an electrical condenser is"
An electrical condenser (AKA capacitor) is not the same thing as an A/C condenser (a heat exchanger).

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Capncorroded

I haven't driven it at all - too much snow on roads. Flashing SES and down 1 cylinder should not be a default or relearn ecu from disconnecting a battery.

I Don't understand the edit statement.
As a current seasoned hvac technician with a large automotive background, I know the difference, but thanks for the basics lol...thus why I said "which I don't believe"

zer099

Do you have the equipment to check the wire at the ECU and that it is indeed sending the signal to the coil? I, and a couple others over the years, had a similar like issue that turned out the that ECU **** the bed. Worse case scenario, but worth the check.

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Capncorroded

Capncorroded

No, I'm not sure whats needed to test something like that. FSM does not show any physical voltages that can be measured on the signal wire. Unfortunately I'm thinking its ECM related.

nis350

just take it to the dealer assuming it is under warranty.

Capncorroded

I know modern cars are more computer controlled, but does anyone care about why things malfunction anymore? Warranty doesnt last forever...

Capncorroded

Just to follow this up - Dealer confirmed the ECM failed. (as I kind of expected)

there was no reason why they could find. Dam electrical stuff.

SouthArk370Z

Thanks for the update. Glad you figured it out.

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Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma

GrayGhost

It is possible for me to be blind/oblivious, but where in the FSM did you find the procedure to diagnose a misfire?

How did they test the ecm to determine it failed?

I have been chasing a random misfire code for some time. Changed out spark plugs, tested each coil pack, and did a vacuum leak test. No findings. Doesn’t feel like i have a misfire either, just throws the code and i have a high idle 1k.


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Cyber370

Today's so-called automobile technicians simply replace the ECM anytime they can't find the true cause of an electrical gremlin. By them saying they don't know why it failed says it all. If I had my ECM fail, I would definitely want to know why to avoid it failing again.

With such low mileage I find it hard to believe your ECM failed unless you've been storing it outside under a tarp all winter or a place with very high humidity OR your car was a flood damaged salvage car.

I always keep my car hooked up to a battery maintainer when not used for longer than a week. Today's car electronics require a fully charged battery at all times.

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Capncorroded

https://www.nicoclub.com/FSM/370Z/Coupe/2016/

EC - Page 297 Is where I started with the Misfire codes. I had a general misfire (p0300) and a constant Misfire Cyl #2 (P0302)

I read the technicians hand notes about his diagnostic procedure - He pretty much did everything I was capable of doing with a multi-meter, but was able to read some more in depth stuff with Consult and a scope. He did (according to his notes) verify the ecm was not sending a signal to cyl #2.

When I was testing, I had continuity of the signal wire from the ECM harness to the coil pack harness I knew there was not a broken wire, and figured it was the ECM. I was just not capable of testing the actual ecm.

Capncorroded

Car is stored in a clean heated garage, low humidity for CNY in the winter, was def not a flood/salvaged car, and no signs of rodents or anything. The day before, I even started it up and pulled it out to turn it around and it was fine- then boom, all sorts of issues.

Being an HVAC technician myself, I have to deal with loads of control boards, miles of wiring, various sensors, harnesses etc, and have had multiple situations where I have had to replace control boards without a direct reason of why the board failed - Do I like that? nope, not at all. I def want to know what happened so it doesn't happen again, but sometimes it is what it is.

Hug0

Hi everyone, I am tracking down similar problem with my 2009 370Z with Uprev and exhaust, intake, etc.. 160 000km

Couple weeks ago car started turning off fourth cylinder. It was after cca 15km drive and only mornings (around 5°C). After Turning off engine, error was gone.

Than it runs normally for couple days. Than again same error. And again, just turn off engine and everything was normal after new start.
There was no error codes.

After week, I finally read codes on running engine and it was P0304 cylinder misfire.
Than sometimes turning off engine does not help.

So I changed all spark plugs and move coil from 4 to cylinder 2.

After that, I am running on five cylinders all the time. Same error code.
I tried spark with coil and spark plug from another cylinder and there is no spark on cylinder four.

on coil sockets there are three wires, one is 12V when ignition is on, second one is ground and on third one I found some readings with multimeter cca 0,6-1,2V in impulses when starting engine. But I am really don´t know if its correct or not.

Also I changed left cam sensor for right one, still same problem.

I really hope its not dying ECU..

Uprev and everything else was there before this problem and worked well.

Any ideas, please?