The O2 sensors or automotive oxygen sensors make contemporary fuel injected – electric - and emissions control possible.  What these sensors do is to determine if the air fuel ratio exiting a gas-combustible engine is loaded with unburnt fuel vapors or has very little excess oxygen.

According to real-time sensor data, rather than operate with a predetermined open-loop fuel map, close-looped feedback-controlled fuel injected varies the fuel injector output.  Although to improve overall engine operations, there needs to be a reduction in the amount of both oxides of nitrogen and unburnt fuel from entering our atmosphere.  Air-borne hydrocarbons or the unburnt fuel in pollution form, while oxides of nitrogen are the results of excess air in the fuel mixture which can cause acid rain and smog.

How to install universal oxygen sensor
There is essentially 8-step to installing a new Universal oxygen sensor.

1] Remove the old sensor, which is normally located in the exhaust type, or manifold.

2] Lay the new Universal oxygen sensor next to the old oxygen sensor and using a wire cutter cut the new one to the size of the old one. 

3] Strip 3/8” of the wire insulation from all the wire ends. 

4] Use the color table in the installation instructions to install the connector over the expose wires. Don’t connect your sensor if you cannot match wire colors.

                          Type A       Type B     Type C      Type D     Honda     GM     Titania 3W     Toyota    Titania 4W
 
OE Signal           Black          Blue         Gray           Gray        White    Purple      Black            Gray        Yellow
 
OE Heater          White         Black       Black         Black       Black    Brown       Red             Brown       Red
 
OE Heater          White         Black      Yellow          Red        Black    Brown      White            White       White
 
OE Ground          Gray          White                                        Green      Tan                              Blue        Black
 

5] The wire seals are then placed over the color-coded caps. 

6] Connect the two ends in the middle without twisting or criss-crossing the wires, again using the color chart to match which wire goes with which wire. 

7] Push the wire cap into the body case of the wires until everything locks into place. 

8] Reinstall the Universal sensor back into the car in the same location as the original sensor.  Making sure you keep the wires away from any hot spots or possible abrasions.  And now you have installed an oxygen sensor.