SupraIV Oxygen Sensor Error

I had the same issue on my SupraIV. Turned out to be a defective cable or plug connection to the sensor. Check the cables first, it's a common problem. Has the catalytic converter been checked?

Which cable are you referring to and where is it located? I'm not very experienced. Haven't checked the catalytic converter yet.

The cable connection directly on the oxygen sensor. Usually sits in the exhaust pipe before or after the catalytic converter. If unsure, visit a workshop to save time and potential costs.

It was exactly as you said: a defective cable connection to the oxygen sensor. Repair cost 95€. Everything is working fine now!