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.

You can check www.napaonline.com
or google 'auto parts'. There are several possibilities, however my suggestion with the O2 sensor is to stick with dealer parts or go with NAPA, you never know what you are getting with other parts places... I am not sure which is bank 1 sensor 2, I am sure that the bank refers to 'left side or right side' of the engine, there are usually sensors before the cat and after, but I am not sure which is 1 and which is 2.

you might be right on, but your code tells you it can,t read sensor data right, it doesn,t mean it is a sensor, it might be plug, wire, just check those too,cuz i had a few customers that replaced sensors, to find out it wasn,t the problem.

bank 1-cylinder bank with cylinder 1
gonne be on the right side of the motor(closest to the firewall).
sensor 2-
furthest downstreem sensor.
folow the exhsut system on the right side of the motor. it will be the second sensor in the system.
what was the exact P-Code? if they didnt give it too you, bring it to advanced or autozone, have it checked out for free, and give me the code.

OH, thank you all, you guys really make me feel better. The error code is "PO141 O2 sensor heater fault(bank 1 sensor 2)" and "PO 401 EGR " .

start by changing the O2 sensor. then have your EGR system checked out.

the mitsubishi part number is md357265 ihave one in stock brand new mitsubishi
$147.19 plus freight

WOW! Thats pricey.

They range from $62.50-$108.98 (depending on which sensor and which brand you want) on www.oxygensensors.com shipping is free.

http://www.automedicsupply.com/catalog.php?&pkey=1374397#Location1