Because I have no dealer in my city, and no one has a CONSULT-III either, I'm forced to travel if I wanted Nissan services.

There's a problem with my ECM, it doesn't communicate over three OBD port, it never has. So I bought three cheap ECMs from ebay. I have a trip coming up to a city with a Nissan dealer that can program an ECM. My plan is to install an "ebay ECM" and get my car to the dealer, get them to program it to work on my car. I have two concerns:

1. I would be taking out my original ECM and storing, even if it wasn't for a long time, would that affect that ECM? And how?

2. Is the BSM involved in this process? Would it be affected?

What else should I think about or keep in mind?

Thanks!

The old one can store as long as you don't have it say out in the rain, use some sense there. The programmed software stays in place.

If you have something wrong with the car that wrecked the communication ability then that same issue could mess up other ECMs put in the car...........I hope as well you have bought the same year and model as yours; not all of the rest may work. They can get changed up and pretty often.

Your harness could easily be the problem and not the computer at all, a single wire broken internally could do that.

I followed the FSM to diagnose the OBD not working problem I had, with a multimeter, everything appeared to be normal except the ECM themselves. So I'm confident the wiring is okay.

I couldn't find the same year ECM, how bad a problem would that me?

My country uses km/h, and so does my Altima. The ECMs I bought were all from US cars (where they use mph), would this be a problem?

My big question though is the BSM, if it detected a different ECM would that screw with my FOB programming?

the repair manual says how to reprogram the car so the bcm and ecm work together.