My 99 Accord doesnt start without the help of my autoscanner hooked up. I replaced the fuel pump.and main relay. I came to the conclusion that its probably something electrical, i had some help troubleshooting it and was told that its my ecm under my center console. So i bought a new one and im getting ready to replace it but the problem is im hearing mixed things, im being told that i have to reprogram it because of the immobilizer and im hearing that i can just plug and play. I guess my question is what should i do in this situation?
I have a 99 accord 4cyl manual transmission 4dr.

 

Call a dealer and give them the VIN number and ask if you need to reprogram or not with a new ECM. I think, but am not sure, that starting in 1998 the immobilizer is an issue and it must be re-programmed. I have heard that the 1997 was the last year that the car did not have an immobilizer (and that made it a top target for car thieves). Scotty Kilmer has a YouTube video on "Fixing a car that won't communicate with a scan tool" You might want to watch that.

 

This is inaccurate info.

 

First check Ground G101, located on the intake manifold plenum.

If the car only starts with the scan tool connected, the scan tool is probably supplying the ground.