Oxygen sensor replacement on w140 S500
I need to replace the oxygen sensor on my 94 S500 so I bought a new one. THe new sensor has a loooong connecting cable whereas the old one only has about 6 inch long cable with a round connector at the end. Is there only one oxygen (I've read someplace about "upstream/downstream" stuff) sensor? If there is only one, what could be the problem with the cable?
Thanks in advance!