Chrysler Repair: O2 sensor, oxygen sensor, co2 sensor

Question
where is the co2 sensor located and how do i test it

Answer
Hi Chris,
The Oxygen (O2) sensor(s) is located on the exhaust manifold and in newer cars near the catalytic converter as well. It looks like a spark plug and has 4 wires coming out the top. The engine control computer is constantly observing it, and whenever it sees a malfunction it turns on the check engine light and stores an appropriate code in its memory. Thus, reading out the memory of the controller for fault codes will reveal any problem. If the vehicle is '96 or newer you can get a readout for free at most Autozone parts stores or for around $40 at an independent shop. For '96 and older you can turn the ignition key "on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light to begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat the process to assure an accurate count. Group the counts in pairs in the order of appearance to form the two digit fault code numbers. The number 55 will always be the last code, it means end of readout. An oxygen sensor code is: 21 and in some cars a 51 or 52. Let me know what you get and tell me the engine and year model.
Roland