Oxygen sensor terminology can be confusing. Here’s a guide to deciphering it all.


From: garysautotechclub (Yahoo Group) , Author : overtork187


Oxygen sensors are described as “upstream” or “downstream.”
An “upstream” sensor is located near the engine, typically in the
exhaust manifold. A “downstream” sensor is located near the catalytic
converter. Though both perform the same function – measuring the
proportion of unburned fuel and oxygen in the exhaust – the differing
data points allow the engine computer to determine whether all of the
components in the engine management and emissions systems are
properly functioning.

That means, of course, that there will always be at least two O2
sensors in any vehicle – at least those built after 1996, when the
emissions regulations requiring oxygen sensors became law.
Usually, however, there are more – often as many as four.
Any car with a V engine (V-6, V-8, etc.) will have two upstream
sensors, one for each cylinder bank. These are called the “bank 1”
and “bank 2” sensors. Bank 1 is whichever cylinder bank has the
number one cylinder. That’s the one that fires first in the firing
order. (All cylinders on an in-line engine are bank 1.)
The number of downstream sensors varies between manufacturers and
vehicles. One will always be located downstream of the catalytic
converter, so that there is a measure of the converter’s efficiency.
But many car makers use two downstream sensors, one somewhat before
of the catalytic converter and the other after it.

Sensors are also described by the number of wires employed: three,
four, or five. Because O2 sensors don’t function properly until they
reach an operating temperature of about 600ºF., modern practice is to
electrically heat the sensor so that it functions as soon as the
engine starts. How that is accomplished determines whether three or
four wires are used. The latest technology in O2 sensors,
the “wideband” sensor, uses five wires. You must replace a sensor
with one that uses the same number of wires as the original.
Sensors are either “universal” or “direct fit.” Universal sensors are
designed to fit multiple vehicles using the same sensor “bulb,” the
part that sticks into the exhaust. But, universal sensors do not come
ready to install. The electrical connector will have to be assembled
first. In contrast, a direct fit sensor is ready to install right out
of the box and simply plugs into the existing wiring.

Which sensor do you replace?

A scan tool or code reader will retrieve the diagnostic trouble code
set as the result of an O2 sensor malfunction. Trouble codes are
specific to the sensor, so the trouble code will effectively
designate the sensor which set the code.


Check out this Obd2 Scan Tool for retrieving codes

Automotive Scanner Could Be Good For The Environment

Using a car scanner or scan tool can be a big step in the air quality that we breathe. Why? Because you can see if an oxygen sensor in your car is starting to be faulty. A defective oxygen sensor can trick your car computer’s to run the car too rich or too poor. Then you can smell unburnt gas coming out of exhaust pipe.Using a scan tool like the Elmscan5 can make you locate the faulty sensor. Of course you need also a desktop computer or laptop for reading the scan tool’s results. A good scanner will make you do live results with the car running on the road. This is the best way of testing various sensors or fuel injectors on you automobile. A footnote:the obd2 system is designed to monitor the emissions performance of the engine.You read the oxygen sensor or O2 sensor results like this: the voltage output of the O2 sensor should read minimum 0.1Volts (lean) and maximum 0.9 Volts (rich). A good oxygen sensor should produce an oscillating waveform at idle that makes voltage transitions between 0.1 and 0.9 Volts. A bad sensor could be always stuck at 0.45 Volts . If you look at the output of an oxygen sensor with an oscilloscope with a good sensor, you will see a oscillating waveform (sine wave).With a very good Obd2 scan tool, you see see the graph of the output of the sensor like you were looking at the monitor of an oscilloscope. You must also see the voltage reading of all sensors including the O2 sensors with the smallest delay possible.

In conclusion, if you monitor your car’s emissions performance of the engine. You can replace faulty or near faulty O2 sensors. You will gain performance of the engine because a car run much better with new oxygen sensor. You will burn less full and you will pollute less in our precious atmosphere.

Check it out: http://www.carplugs.com/obd2usb.html

What is the difference between OBDii, OBD-II, OBD ii and OBD2

What is the difference between OBDii, OBD-II, OBD ii and OBD2?

Answer: None, It seems that different corporations used different terminology. The items like connectors, cables or scan tools have no standard of writing except of the OBDii connector should be called J1962.

If you look at some search results on MSN, Google, Yahoo or ASK, the most popular one is OBDii. Personally, I like more the OBD2 term.

For OBDii Connectors, OBDii Cables OR Scan Tools Go to www.carplugs.com


Mario I.