I have a very important question and I need an answer right away. I have a 2006 mazda 6 3.0. I need to know where is the bank 1 sensor1 O2 sensor is located. I have heard two different answers. What's the real answer and does anyone have any real good pics please

 

Bank 1 is the side where #1 cylinder is. Unfortunately it is the one at the back by the firewall.
Sensor one is the one just before the pre-cat (actually it is just in the front of it). It monitors air/fuel ratio just before the exhaust goes in to the pre-cat.
Sensor 2 would be the one on the far side of the pre-cat as sensor 2 monitors the exhaust after it goes thru the pre-cat.



THE FOLLOWING IS A PIC I TOOK OF THE FRONT ONE ---- SENSOR CLOSEST TO YOU IS SENSOR 1





The sensor you want is the one in the exhaust pipe of the engine cylinder bank that has #1 cylinder in it, as you face the engine with the hood open the cylinder bank u want is the rear bank, u will need to jack the car up and get under it to remove the sensor, u may also need a special socket to remove it, the sensor is the one that is before the catalytic converter. part number is: DENSO Part # 2344068
REAR; Before Catalyst

 

Thanks Noggin, appreciate it.

 

Just had the garage do mine on my cougar as I just couldnt get to it - it waas easy for them with garage ramps and was cheap as I supplied the sensors