Service function guideOxygen Sensor Replacement and Test

This guide walks a working technician through the complete replacement and verification of a heated oxygen sensor, from understanding the zirconia and titania sensing elements to interpreting live scan data after the repair. It is written for mechanics who already own a scan tool and a digital multimeter and who want a repeatable, diagnostic-first workflow rather than a parts-swapping guess. You will learn how to test the heater circuit and the signal circuit before condemning the sensor, how to remove a seized sensor without damaging the exhaust bung, and how to confirm the fix with fuel trim and switching data. By the end you will be able to diagnose, replace, and validate an oxygen sensor on most gasoline vehicles and know when the fault actually lies elsewhere.