Oxygen Sensors (o2) Concerns Everybody!!!
 

Okay, I have changed O2 sensors on my 2000 E320 and my 2000 CLK320 before and I have run into many problems in trying to locate the faulty sensor. I hope that an experienced Mercedes owner can tell me with 100% certainty what the terms Bank1 and Bank2 mean.

From my current understanding

Bank 1 = Driver Side (aka Left Side)
Bank 2 = Passenger Side (aka Right Side)
Sensor 1 = Front (before Catalytic Converter)
Sensor 2 = Rear (after Catalytic Converter)

Is this correct????? Please, someone who is sure of his answer, because even mechanics have told me different things. Is it confusing maybe because Bank1 can be different on certain cars???

cdplayer
 

Your cars have OBD II diagnostics onboard. If you can retrieve the codes with a scanner(for the DIY) the code (if any) will zero in on the bad sensor and tell you this.
I have two Mercedes and fortunately I have not experienced this problem. But with my Jeep Grand Cherokee, the check engine light came on. Using a code reader I got online, I read code #P0158. checking the manual that came with the scanner, P0158 refers to 02 sensor bank 2 sensor 2. Then using the shop manual I have on CD for the Jeep I looked at a schematic of the emmissions control of this vehicle. The schematic confirmed Bank 1 is the driverside. Sensor 1 is above and sensor 2 is below. Bank 2 is the passenger side with sensor 1 above and sensor 2 below.

Granted you said different makes may have different setups. But most important is getting the code. Maybe then someone on this forum can explain the meaning of the code you retrieve and direct you to the correct sensor. Good luck.

Appreciate the advice, well said. I hope an owner of a 2000 CLK320 can tell me what Bank1 and Bank 2 means.

bank 1 always refers to the bank where the number 1 cylinder is located. for your 3.2 liter V-6s, that would be the front right cylinder.

the right and left nomenclature refers to the vantage point from sitting in the driver's seat; this is industry standard and refers to the entire car i.e, RF tire, LR brake light, etc.