Good Morning, everyone. I have a pristine 2000 Red label with approximately 13000 miles, always stored indoors. The check engine was going on and off occasionally, and now it is on again. When it was plugged in yesterday at my Mercedes dealership where I work it said " 02sensor 1, bank 1". My question is there more than one sensor in this engine, and how difficult are they to replace ? Will driving the car with this warning cause any problems? Of course I intend to have it corrected . I only put about 500 miles a year on it, mostly nice Sunday morning drives and car shows. Thank you all in advance for your expertise !!!