Ractis oil temperature sensor warning

Could be the sensor. Before replacing it, did you check the cable and plug connection thoroughly? Sometimes a loose or corroded connection can cause these symptoms and throw false readings. Double-check before buying a new sensor.

Good point. I visually inspected it, but I haven't tested the connection with a multimeter. What voltage should I be looking for at the plug, and where can I find that info?

I wouldn't use a multimeter unless you know what you're doing. Given the oil pressure light too, it's worth having a workshop take a look. It could be more than just the sensor. Don't risk engine damage.

You were spot on. It was a defective cable/plug connection, like you suspected. They cleaned everything, replaced a small section of the wiring, and now it's running perfectly. Cost me 95€, which is way better than a new engine! Thanks for the advice!