Insignia Exhaust Temperature Sensor Fault

Sounds familiar! I've got an Insignia too, although a slightly older model. I had similar symptoms a while back. Reduced power, the light, the whole shebang. Did you notice any hissing sounds, or maybe a stronger exhaust smell than usual?

No hissing, but I do get a whiff of exhaust fumes sometimes, especially when the engine is cold. Was it definitely the exhaust temperature sensor in your case? Was there anything else involved?

Yep, it was the exhaust temperature sensor alright. Turned out the sensor itself was fine, but there was a small crack in the exhaust manifold near the sensor. The garage spotted it pretty quickly. I'd suggest getting it checked out by a professional – save yourself the headache.

Thanks for the advice. I took it to a local garage, and you were spot on. Crack in the exhaust manifold near the sensor, leading to sensor failure. New sensor and a bit of welding, all in for 265€ Appreciate the help!