SupraIV Oxygen Sensor Heater Failure

Hey, I had something similar with my SupraIV. Check engine light and increased fuel consumption are dead giveaways. It's like your car is telling you it's not breathing right! Have you checked all the connections to the oxygen sensor to make sure they are clean and secure? Which sensor is throwing the code? Knowing if it's upstream or downstream can really narrow things down.

How would I specifically identify whether it is the upstream or downstream sensor that is causing the issue? Are there particular diagnostic procedures or visual cues?

Identifying the sensor usually involves looking at the specific error code your diagnostic tool is giving you. The code will usually indicate which bank and which sensor is the problem. For example, something like P0135 refers to Bank 1, Sensor 1 (usually upstream). If you're not comfortable diving into that, a quick trip to a trusted workshop might save you a headache. They can pinpoint it quickly and confirm it's not something more sinister. A faulty heater element in the O2 sensor is pretty common, and if that's the case, it’s a relatively cheap fix.

Following your recommendation, I consulted with a qualified mechanic, who confirmed the oxygen sensor heater failure. The defective sensor was replaced, and the total cost was 95€. The issue is resolved, and the vehicle is now operating normally.