I recently got a CE light on my 96 C280, its the oxygen sensor but I am wondering where is "Bank 2 #1"? For future referance where is Bank 1? Is there a #2 on Bank 2? The car has 173K on it now, should I just replace both? Presuming there are only two. Last but not least, will I need a special tool?

Thanks,
Brad

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1986 190E 186K (For Sale)
(Maroon, Tan leather)
1996 C280 Sport 208K
(Brilliant Silver, Black Leather)
2002 CLK430 Sport 45K
(Brilliant Silver, Gray Leather , Birdseye Maple)