1994 E420 Oxygen Sensor
 

Cannot find anywhere the description of the wires coming from the plug.
4 wires:
2 whites
1 grey
1 black.

Which one is the signal?

I assume the other 3 are just heater and does not matter where they connect.

The New Denso sensor has 2 black, 1 blue (signal) and 1 white.

I am trying to match them up.

I think this is it.....just through google search

OE Heater White = Black = Black = Brown = White

OE Heater White = Black = Black = Brown = Red

OE Signal Black = Blue = White = Purple = Black

OE Ground Gray = White = Green = Tan

Edit:

Here is a better link

http://reviews.ebay.com/UNIVERSAL-OXYGEN-SENSOR-INSTALLATION-INSTRUCTIONS_W0QQugidZ10000000000991989?ssPageName=BUYGD:CAT:-1:LISTINGS:1

Thanks guys.

I finally found the diagram in the CD.

White and White are the heater .

Grey Ground and Black is the signal wire.