SMAX Oxygen Sensor Issue

Greetings. Your predicament is not unique. A similar issue presented itself in my previous vehicle, a 2015 Opel Insignia, equipped with a comparable gasoline powertrain. The symptoms you describe, namely the illumination of the check engine light coupled with a discernible increase in fuel consumption, are indeed indicative of a potential malfunction within the oxygen sensor circuit. Have you undertaken a thorough inspection of the sensor's wiring harness and connector for any signs of physical damage, corrosion, or loose terminals? Furthermore, have you considered employing a diagnostic scan tool to ascertain the specific fault code(s) associated with the oxygen sensor?

Thanks for the insight! Yes, I gave the wiring a once-over, didn't spot anything glaringly obvious like frayed wires, but I'll admit, it wasn't the most meticulous inspection. As for the diagnostic tool, it's spitting out codes related to the O2 sensor leaning out. What exactly should I be scrutinizing on the wiring harness?

Affirmative. Given the diagnostic trouble codes indicative of a lean condition, it would be prudent to conduct a meticulous examination of the wiring harness, specifically focusing on the integrity of the ground connection. A compromised ground circuit can induce erroneous sensor readings. Should the issue persist despite these measures, the sensor may be defective and replacement is recommended. You might want to consider consulting a qualified technician.

Roger that! Cheers for the detailed breakdown. Took it to my local garage, and you nailed it – dodgy connection plus the sensor itself was on its way out. New sensor and connection fix, total damage 95€. Runs like a dream now!