Oxygen (O2) Sensor Service Video

The oxygen sensor measures how much unburned oxygen leaves your engine through the exhaust. That reading tells the engine computer whether the mixture is rich or lean, so it can adjust fuel in real time.

This video shows where the upstream and downstream sensors sit on the exhaust. It also shows what a contaminated sensor looks like after years of heat, and the codes a failing one tends to set.

A check engine light with codes in the P0130 to P0167 range usually points to a sensor or its heater circuit. Rough idle, hesitation, and a drop in miles per gallon are the symptoms owners notice first.

An inspection checks live data for switching speed, heater resistance, and fuel trim behavior before any sensor comes off. A healthy upstream sensor switches between rich and lean several times per second, while a lazy one holds flat. When testing confirms the fault, our engine diagnostics service explains the full process.

Short winter trips around Grant County keep the exhaust from fully warming up. The sensor leans on its heater circuit longer, which wears the heater out sooner.

If your check engine light is on or your mileage has dropped, call Affordable Automotive Services at (509) 764-0000. Need a mechanic in Moses Lake Drivers from Ephrata and Quincy bring us sensor codes because every sensor is tested before it is replaced.