Hello,
I have G37 '12 sedan and I tried to install phoenix tesla unit, from here to there I had the wrong tesla harness so I return back to stock( I have to say that few times I forgot to disconnect the battery).
I returned all the connectors back to original place and connected the OBD unit( I did that due to the Pedestrian safety systems warning light which I also want to reset) and found this error -


Tried to reset it but it came back.
Any thoughts?
Thanks.

 

The ECM is supposed to receive 12V constantly- whether the car is running or not. This code is basically telling you that when the car is OFF the ECM is not receiving power. That said, being you attempted the Tesla knockoff install, the issue is likely with the harnesses and/or, because you didn't disconnect the battery before doing the install, a blown fuse.

- double check all of your harness connections;
- double check ALL of your fuses- specifically those in the fuse block (IPDM) located next to the battery.

While not likely your issue, it would not hurt to check for any water leaks around the ECM area. These cars are becoming more common for sunroof drain leaks. Again, likely not your issue but while you are in there...

 

Thanks mate, I will check it.
regarding the water issue I don't think it is relevant as the car park in a dry place and didn't get out for more than 2 weeks
P.s.
where is the ECM located?

 

The ECM is located behind the glove box.