OBD2 Scanners – What is Mode 5?

Federal law requires that almost all light duty cars and trucks come equipped with an oxygen sensor, often refereed to as an “O2” sensor. This part helps measure the richness of the fuel mixture, taking into account many factors, including air temperature, coolant temperature, barometric pressure, air flow, and other variables. Essentially, the oxygen sensor is the supervisor for what’s happening with the fuel mixture.

Consequentially, a problem with the oxygen sensor can result in a major problem with the engine, exhaust, fuel efficiency, and more.

This is where Mode 5 comes into play, displaying oxygen sensor data and test results, and giving technicians a way to accurately diagnose and repair the oxygen sensor system.

Mode 5: Oxygen Sensor Monitoring

Mode 5 is usually available only on more advanced and higher-priced scan tools. When a scan tool is equipped with Mode 5 capability, it will display oxygen sensor monitor screens as well as give oxygen sensor test results.

One of the most handy applications of Mode 5 is diagnosing air/fuel mixture test results. An engine will use a varying mix of air and fuel, depending on many factors and variables, and Mode 5 can give you detailed information related to the fuel mixture. This is especially useful for people concerned with gas mileage or performance.

An oxygen sensor also generates a small voltage, and Mode 5 can be used display minimum and maximum voltages, again giving a mechanic another set of data that is useful in diagnosing and repairing issues.

If an oxygen sensor goes bad, it can create numerous problems for an engine, and some technicians have even recommended replacing the part on a regular basis to maintain peak performance and maximize fuel economy.

Monitor Your O2 Sensor with Mode 5

Whether you own a small, fuel-efficient commuter car or have a drag racing muscle car, you will benefit from owning a scan tool equipped with Mode 5.

While you’ll have to pony up the cash for a more advanced unit, Mode 5 will help you make sure that your vehicle’s oxygen sensor is running perfectly, giving you better performance on every trip.

Summary of all OBD2 Scanner Modes