AMG GT Hybrid Check Engine Light and Exhaust Issues

I had a similar issue with my older Volvo XC90. Check engine light, reduced power, all the fun stuff. In my case, it turned out to be a faulty exhaust component, probably what you called an exhaust sensor or maybe a heat sensor. Before you go too far down the rabbit hole, have you noticed any unusual sounds coming from the exhaust? Any hissing or popping? These can be signs of a leak in the exhaust system itself. Also, are you able to read the error code that's triggering the check engine light? That would give you a much clearer idea if it is the exhaust sensor.

Thanks for the reply! No unusual sounds that I've noticed, but I'll definitely listen more closely. I don't have an OBD reader myself. Do you think it's still worth trying to diagnose further without knowing the exact error code? Or should I just bite the bullet and take it in?

Without the error code, you're flying blind. Given the symptoms and the potential for damage to the hybrid system, I would not recommend driving it much further without knowing what is wrong. In my case, a small exhaust leak caused the sensor to read incorrectly, which then messed with the engine timing. So, yeah, get it checked out. It will save you money in the long run.

Took it to the shop, and you were spot on! Turns out there was a tiny leak causing the exhaust temperature sensor to give faulty readings. They did a sensor replacement, cost me 265€. Runs like a dream now. Thanks again for the advice!