You sometimes can test an O2 sensor in the vehicle with the engine hot (normal operating temperature) just after shutdown, but for our purposes (and more accurate testing) we’ll bench test the unit.

Your vehicle's O2 sensor plays a significant role in its performance and if it's faulty, it's not something you should ignore. Here's what you need to know.

Rounding out the five most common problems found to trigger the check engine light after ignition coil and spark plug, and O2 sensor were 3) catalytic converter, 4) loose or damaged fuel cap and 5 ...