Before the catalyst, driver side.
It is behind the catalytic converter
passenger side first sensor before cat
Bank one is the side of the engine with cylinder #1. Sensor 2 is after the catalytic converter.
drivers side, after catalytic converter.
on the driver side
I have just found this. I have the same truck and the same problem. Bank 1 means its on the driver side and sensor 2 is the rear sensor. They come off the exaust.
Standing in the front of the engine: Bank 2 is the left head and 02 sensor 1 will be the first and closest sensor in the exhaust pipe were the pipe hooks to the engine.
The bank 2, Oxygen sensor 2, on a 1999 Mitsubishi Diamante is located on the passenger side of the vehicle. It is in the exhaust in the undercarriage.
Is this bank 2 sensor 1 or sensor 2?
Bank 2 is the passenger side of the engine. and the 02 senser is screewed into the exhaust pipe on that side. Work your way back to the muffler and you will see it.
driver side
it is the rear sensor bank 1 (the one after the converter)