This caused two additional codes to store in the system along with the O2 sensor code. Ultimately, loosening and retightening the two ground strap bolts allowed us to clear all the codes from memory.

Answer: Kristopher, as you know, lean oxygen sensor and fuel trim codes can be some of the hardest fault codes to diagnose.

If the Heated Oxygen Sensor (HO2S) indicates higher levels of oxygen content, the PCM makes adjustments to the injector pulse to balance their-fuel ratio.