Corolla oxygen sensor heater failure

Interesting. I had a similar issue with my old Opel Astra, although it was a gasoline engine. The check engine light and higher fuel consumption were definitely present. Did you check the exhaust system for any obvious damage before checking the sensor itself? It could be affecting the heater element's performance. Also, have you tried cleaning the sensor plug? Sometimes it is just a bad connection.

Thanks for the input. The exhaust system appears intact. Can you elaborate on which car components you had to check on your Astra?

Sure thing. On the Astra, after the usual stuff (checking fuses, etc.), I focused on the wiring harness leading to the O2 sensor and the sensor itself. Ultimately, I decided to take it to the workshop. They diagnosed a faulty heater element within the sensor, and replaced the entire unit. That fixed the error for me.

Understood. I appreciate the confirmation; that aligns with my diagnostics. I will proceed with a visit to the workshop. Thanks again.