What is the O2 Sensor and why does it matter?
The O2 sensor is a small measuring device about the size of thick spark plug (a little longer). It is always located ON the exhaust pipe. Older models (OBD1) usually just have one right before the catalytic converter, newer models have 2, 3, 4, and a few have 5. But the only ones that matter are the ones BETWEEN the engine and catalytic converter- these are the ones that measure the amount of O2 (oxygen) coming out of the engine. This sensor then sends a signal to the cars computer to either INCREASE the amount of fuel it’s injecting into the engine, or DECREASE it.
