Which sensor is wich? 2010 Buick LaCrosse CXL

Question

There's 2 sensors in the front of engine one on top and bottom then the other 2 are somewhere below the car obviously but how do I kno wich sensor is a heated sensor or is it all the same?  I have 2 codes of bank 1 lean and bank 2 lean...so wich are the 2 sensors that I need to replace? I kno it might not be the sensors but I want to replace them I just don't kno wich are the 2 and wich ones are the heated sensors..plz help and thx...

Answer 1

HI there,

All 4 of the O2 sensors are heated O2 sensors. With these codes, you want to replace the first sensor on each bank. The sensors BEFORE the catalytic converters. So, it would be the first one in the front bank, and the first one in the rear bank. Because it's affecting both banks though, I would suspect either the fuel pump or the mass air flow sensor to be the problem.