I just recently replaced my upstream O2 sensor in my 2007 MC LS. I cleared the code in the OBD but it came back about 20 min later. I got the trouble code for Bank 1 Sensor 1 & Bank 1 Sensor 2, but I only thought I had one sensor before & after the catalytic converter. Thanks for any help you guys can give me.

 

I'm not sure how the 7th gen Montes are setup, but to my knowledge, there are two O2 sensors as you stated (one before and after the CAT). And if you replaced the one and not the other and you are still getting the code, you probably need to replace the other one as well.

BTW - Can you post the actual code that came up? Some people here may have experience with the specific code you are getting.

 

Yea I just picked up the Haynes manual today & it confirmed it was only 2 o2 sensors but the codes I got were p0030(Oxygen sensor heater control circuit bank 1,sensor 1) & p0036(Oxygen sensor heater control circuit bank 1 sensor 2. I was told that bank 1 was all before the catalytic converter & after the cat. converter was bank 2 so I'm not sure if the downstream needs to be replaced. I really want to get this figured out because I have to pass this emission test soon.

 

Check the wiring for the sensor or the fuses?

 

Nope...bank 1 and bank2 refer to the exhaust systems when a vehicle has a true dual exhaust. bank 1 is one manifold/cat/muffler and bank 2 is a completely separate manifold/cat/muffler. A vehicle only has a bank 2 if it has true dual exhaust.

FYI sensor 1 is the sensor before the cat and sensor two is the downstream sensor.

 

It's cool now I just had to ride around on it for about 50 miles & the light finally went off thanks for all the help though

 

Thats good to know. I just did a bunch of exhaust work and the light came back on after i cleared it the first time. It came up as the same code so i think i am going to drive a bit more and see if it goes back off with the new set up.

 

I'm actually in a current situation with myronprescott. A situation wherein I replaced my oxygen sensor but after a few minutes the error code appeared again. I'm also confused with Bank 1 Sensor 1 & Bank 1 Sensor 2. But thanks to this thread I'm now enlightened but that's a lot of info to digest lol.

 

My understanding is that in a "V" cylinder configuration is that Bank 1 refers to the side of the engine that contains cylinder 1 and Bank 2 is just the other side. The Sensor 1 is usually farther towards the top of the motor, Sensor 2 is farther back and so on until you get to the one after the cat. The trick, I've learned, is that you have to know how many sensor there are on each side of the motor to find them all and follow them numerically.