Ok, I checked for power to the ecu just in case.
the manual shows 1 pin for each of the 2 back plugs constant power.
1 plug for each with key on power.
I found that, but they don't match the pin out given in the manual.
I got the new ecu and it acts the same. the ecu isn't reading from a code reader at all.
about to go check all the fuses, but is there something I a missing?
I have tried unplugging everything and reseating it, but that didn't help the other ecu either.

 

Fuses and fuse links should be checked first before any kind of electrical diagnosis is ahead. Sounds to me like CANBUS issue, the ECM is not connecting with BCM which runs the show. You'll have to check for continuity between BCM and ECM comm wires. Just because there is power, it doesn't mean they communicate. Kind of like my 2021 Explorer, it needs reconnecting of few modules for them to talk to each other.

 

thanks. I figured if there was power the fuse was probably good, but didn't know where to go after that.
I will check wiring for the ecm to bcm.
the bcm is communicating through the obd port.

 

I couldn't find anything in any of the diagrams that show a direct connect from the bcm to the ecu.
I tried to run a continuity test from the obd2 port to the ecm, but almost everything had continuity to all the other pins. so don't know what to make of that.
all the fuses I could get to seem to be good.
There is that black box next to the battery and I could not get that open.
is there actually a can bus box or something to get to to check?

I also get why you say I need the other tool. It says that I might not be able to communicate to the ecu over the k-line,but the actual scanners use the can bus to communicate.

I really am not sure what that would tell me at this point. but I guess I might have to give it a try.

I am really stumped how all of this could happen after just replacing the gallery gasket set.

any idea if this is a reputable place to get one
https://www.vxdiagshop.com/wholesale...ssan-tool.html

 

The black box is the intelligent power distribution module (IPDM).

 

thanks, any idea how to open it? there is a tab on the top end, but it won't open even after prying it up so it isn't hooked anymore.

 

https://www.nicoclub.com/service-man...2008%2FPCS.pdf

Pages 34 & 35. You should sign up at nicoclub and download the entire service manual for your car. You can do a self test of the IPDM. Instructions are somewhere in there. It involves the ignition key on and pressing the door lamp button 10 times. Nissan IPDMs are famous for taking on water due to the lousy electrical design where it is placed under the windshield cowl.