What is this?

I don't know what it is but it's correct and there's nothing wrong there's a few of these on quite a few Toyota models I don't know if there's some kind of a ground business or if that little square thing that is plugged into is I don't know what electrically Don't really care but I know you don't want to go cutting and hacking and messing with that stuff

 

that's a noise filter and it's a 1 wire plug. If you look closely there's 1 wire connected.

 

If it's a noise filter like high mileage garage says then it just cleans up signal noisy dirty signal electrically some kind of a filter I know there's quite a few of them throughout the car and I just leave them alone I don't think they're things that will really go bad and create serious issues they're like noise filter canister

 

it suppresses electrical noise caused by the ignition coils. If this fails you could hear a background noise in your AM radio that varies with RPM.