P0302 Cylinder Misfire
 

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?

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).

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"

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.

https://www.facebook.com/photo.php?f...&theater&ifg=1
https://www.facebook.com/photo.php?f...&theater&ifg=1

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.

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

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

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.

Thanks for the update. Glad you figured it out.

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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P0302 Cylinder Misfire
 

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.

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.

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.

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.. :confused:

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

Any ideas, please?

Possibly a wiring problem. FSM (link in my sig) has wiring diagrams and will tell you what kind of signal to look for at the injector. Also lots troubleshooting procedures.

With my situation last year I diagnosed it as the ECM. The dealer confirmed it with consult and swapped it out. Luckily I still had a warranty. No problems since.

My theory about why it went "possibly", was error on my part and leaving the key fob in the cup holder during storage. Ive always left the keys in my stored vehicles, and completely forgot about how there is a "wake up" of some features when the fob is in range.

If you want to troubleshoot the ignition coils, you will need to scope the current of each ignition coil on the primary (low voltage side) typically the coil ground.

When you look at all 6 waveforms, you will quickly find out which one is different and that is the bad one.

If haven't used a scope or don't have access to one, then you might want to take it in to a good shop.

Thanks for advices.

SonicVQ:Coils are OK. Also I am 100% sure, that problem is only on cylinder 4.

I tried some troubleshooting. Can somebody tell me what is condenser with connector F8? And where I can find it? I can´t find any pictures of it. I know what it should be, but I cant find it anywhere :/

The condenser is difficult to find as it is taped to the wiring harness that is under the upper intake.

http://www.the370z.com/attachment.ph...1&d=1590759051

This is what it looks like:
http://www.the370z.com/attachment.ph...1&d=1590759051

Thank you!!!!

Little progress: I tried osciloscope today. On cylinders which are OK, there is 5-6V signal on signal wire on coils. On fourth cylinder, there si similar signal, but only 2-2,5V.
Wire from ECM to coil plug seems to be OK (checked with multimeter).

I really hoped, that problem is caused by bad wire, but It kinda looks like ECM problem :(

Should I try to change signal wire from ECM to coil? According to my uncle (electrician) wire is 99% OK.

Now that you have a scope, I think the next step is determine bad coil, vs bad wire/ecu.

Set up the scope and get a screen capture (use phone if there isn't a built in function) of cylinder #4 signal wire and either #2 or #6 ignition coil.

Move ignition coil #4 to #2 or #6, and take screen shots again.

Compare the pictures and see if the lower voltage signal wire moves to #2 or #6 or stays on #4. (posting the pictures would also be helpful to me)

• If the low voltage signal moves with the coil, I would suspect a bad coil.
•*If the low voltage signal stays on cylinder #4:
• check coil ground and 12volt supply

Since the original problem got worse after changing the plugs, I would focus on the wiring and check connectors for burnt or bent pins.

When checking wire resistance, it is important to keep in mind that the meter uses a very small current for the resistance test. The ignition coils uses a fairly high amperage of about 12 amps for 0.005 seconds when at idle. (I have scoped my G37's ignition coils)

This can result in the meter showing a good connection, but it may not be a good enough connection for the current draw of the coil.

Additional thought:
Over the years I have tried to help many people with car/engine problems.
About half the time, aftermarket add-ons have directly or indirectly caused the issue.
Melted wires, wires pulled too tight and break internally, loose connections, missing grounds, etc.

With this in mind, please double check any modifications that have been done looking for the items mentioned above.

Unfortunatelly, I don´t have a scope. My uncle has really old one, so I went to his place and we checked it there.

I took some videos, but I need to check if they are OK.

I changed coils (#2 to #4 and back) before and there was no change. I also tried create spark between coil with sparkplug and ground. On #2 coil socket, there was pretty nice spark, on #4 socket (same coil and sparkplug used) there was none. #4 coil is now brand new from NGK (there was some chinese piece of sh*t from previous owner).
Should I check this again with scope?

I checked 12V and ground and it was OK. I will double check that.

According to mods, I think that only one electric related is Uprev tune. I tried 3 different maps without any change.

I would like to change signal wire, but I am not sure if I can change it myself.

I checked all grounds I could find and clear them. Wires looks OK, there is no obvious tension (but I know, they still can be damaged).

If you haven't already, disconnect the ECU and the ignition coil #4. Check the resistance between #4 signal wire and ground. It should be open.

I think the next step would be to temporarily run a wire from the ECU to the signal wire on the ignition coil.

Use the factory shop manual to find the location of the cylinder #4 ignition coil wire. On my 2011 G37 it is pin #11 and the wire is green. The 370 might be the same or different.


At the ECU tap into the #4 coil wire and run it to the signal wire on #4 ignition coil. Since this is just a test, make it easy for yourself and run the wire out the window to the engine.

** Make sure to use a wire that is about as thick as what is already there. **

The point of the test is to have a known good wire between the ECU and ignition coil #4 signal wire.

• Test for spark strength (like you did before) and compare it to #2 or #6
• Start the engine and check to see if it is running on all 6 cylinders.

I wish you luck and let me know the results.

Hi, little update...

It is open.. No shortage there.

If I connect wire to ECU socket with needle or something, there is no change.
Unfortunatelly, I don´t have that small pins to change whole wire without damaging original one.

I don´t want to cut original wire.
Unfortunatelly I can´t find that small pins anywhere.

Btw: we tried to check voltage with scope by putting needle into ECU socket and there was also only 2V.

I will let you know results after I´ll find correct pins and do a proper test with new wire.

So, here is little update...

I found used ECU socket and coil socket.
So I took new cable and solder pins to it.

And suprisingly new cable did not make any change..
I took it and replace wire for cylinder 2, just to know if my made wire works and it does work fine...

Now it looks like, that all coil wires are OK. There is 12V with ignition, ground is OK and now I can tell that signal wire is also OK.

Unfortunatelly this leads me to ECU...

Look on Ebay. I have seen ECU's for $100.00

I think you are right.
Ebay is a good source for inexpensive ECUs. I have purchased them for as low $50 US (plus shipping, duty and taxes of $50 to Canada, so $100 total)

I believe you will need to have the VIN re-programmed, and re-sync the ECU and BCM so your intelligent keys will work and you can start the car.

-OR-
you can unsolder the EEPROM (95320 4Kb) and move it to the replacement ECU.

-OR-
you can read the old EEPROM and write to the replacement ECU EEPROM.


Good luck!

Thanks!

That is what I am little aware. Immo and ECU settings.

I have MPPS cable with software for downloading and uploading ECU sw (I used it for my VW and BMW), so I am thinking, that I will duplicate my ECU to new one. But I don´t know how about immobiliser?

Also I have ECU MEC107-390 and only one available localy is MEC107-070. I can´t find any info about compatibility.
its around $200

also I can force VIN into ECU thru Uprev SW.

The "MEC107" is not the part number, it is more like a production number.

You need to find out the ECU ID of your existing ECU. It will be something like "6GC2A"

This can be done with an cheap ELM327 OBD scanner and an app like:
• OBD Fusion (in diagnostic reports, under calibration ID)
• NDS III (Android Only and bluetooth OBD scanner only)
• Torque Pro (Android Only under Adapter settings)

The actual part number for your ECU is 23703 + ECU ID, for example: 23703-1UX0A
IF your ECU ID is 1UX0A.

As far as I know, the 370 and G37 use the same hardware for the ECU, but have different programming in the ROM and in the EEPROM that is not part of the SH7059 processor, but a separate 8 pin IC.

You will need to copy the ECU ROMs programming and write it to the new ECU.
I don't think your MPPS cable will work on a Nissan / Hitachi / Renesas ECU.

Also, you will need to copy or move the 8 pin EEPROM that holds the key IDs, VIN and other stuff.

I think your best option is to contact "ByThaBay" (Nissan 370Z Forum - View Profile: ByThaBay).

I think he can provide a pre-programmed ECU that you can just swap in.

Finally some progress!!

I´ve just got ECU from G37. Local company copy my immo there, but they were unable to copy whole SW becouse uprev locked it :/

But I just tried it with stock infinity maps and car runs perfectly fine!!! :happydance:

So I will revert original ECU to stock, copy it to new one and apply uprev maps to it again.

I wanna thank you very much for all your help!!!! :bowdown: