my car is 2001 Diamante LS, 6 cylinder. Failed on SMOG check, it's the O2 sensor, ( Bank 1 Sensor 2 ), can someone help me locate that part that i can buy it online, the quote from dealer is $240.00 which is too much.The error code is "PO141 O2 sensor heater fault(bank 1 sensor 2)" and "PO 401 EGR " .[:@]

 

I am not sure which is bank one on mitsubishi's but, bnk1 sen2 the downstream sensor is at fault there. P0401 is egr insufficient flow so check to see if the egr valve is clogged.

 

Id say first check the vacuum lines to the EGR and the EGR itself. And the o2 sensor is on the exhaust after the Cat

 

Which side is bank 1 and bank 2 on mitsubishi engines?

 

give me the part number ill try to get it cheaper, where are you located?