Both are out of a 2000 4runner limited with federal emissions. I am looking to swap one the two ECUs since I lost the key to one of them. Any help would be appreciated. The junkyard sent me the wrong ECU again...

 

Looks like one p/n replaces the other. Toyota does this a lot.

https://www.toyotapartsdeal.com/oem/...666-35140.html

 

Thanks again! SO basically an upgraded ECU?

 

Probably not. More often it's just a change in producer or component part for cost reasons. They don't tell us, and there is no way to know.

 

I was always told the 1999 immobilizer ECU couldn't be flashed for new keys when ALL keys are lost, I was recently told that apparently that is no longer or never was the case if sent to the right people that specialize in this. I also added a key to an auction truck that had a new none OEM key flashed for it supposedly, so a new ECU with keys wouldn't be necessary if true...