Mitsubishi Repair: montero o2 sensor, o2 sensor, oxygen sensors

Question
I have a 2001 montero with the cel  light on. the scanner I bought tells me I have a code PO174 SYS. to lean,and a code PO154 O2 sensor ckt no activity bank 2 sensor one.  My queston{s} which side is bank 2 and is that on the side of cyl. 2? Would that be the passenger side? Would sensor one be towards the front? Can I check this with a multi meter?

Answer
Brian,
I believe Bank 2 represents the side of the exhaust collector where the O2 sensor is located.  Your car has 2 oxygen sensors; one before the catalytic converter and one after the cat. converter.  Those codes represent a problem with the first O2 sensor.  If you knew the tolerances for your particular O2 sensor, you could check it yourself with a multimeter.  But you may just want to buy a new O2 sensor from the dealership and have it installed.  If you have ever replaced an O2 sensor before or if you've ever done any exhaust work, you could probably do this job yourself.  Else, have a mechanic replace the sensor for you.
Good luck!