So , when I got the 2015  FJ09 it had been remapped ( the guy I bought the bike from was in the USAF and he had the bike shipped to England when he was stationed there and had it remapped over there ) 

Part of the remap included the 02 sensor being removed.

I'm saving to buy a new full aftermarket exhaust system  ( Arrow / Leo Vince / Scorpion / Akra ) so my question is , will I need to replace the 02 Sensor ( $300 roughly ) for the new system or can I just screw in the blanking plate that's fitted to the OEM currently. 

Exhausts are a dark art to me , so I apologise if the question is deemed to be a daft one 😁 

 

cheers 👍

The O2 sensor will have been switched off in the ecu (adaptive learning disabled), so just screw in the blanking plate into the new downpipes.

18 hours ago, roland said:

The O2 sensor will have been switched off in the ecu (adaptive learning disabled), so just screw in the blanking plate into the new downpipes.

Appreciate the clear and simple reply. Makes sense and life a lot easier for when I buy the new exhaust 👍

Sounds like your bike was flashed for stock exhaust. When changing to an aftermarket exhaust system, you might want to look for one that does (or claims to) not require a re-flash to maintain your bike's performance. Just food for thought... unless you're already preparing to re-flash for the new pipe.