XC60 check engine light and fuel consumption

Sounds like it could be a faulty knock sensor. Those symptoms – warning light, poor fuel economy, and rough idling – are pretty common indicators. Have you noticed any difference in performance, like a loss of power when accelerating? It's kind of like when your TV antenna is loose and the picture gets all fuzzy – the sensor isn't properly 'seeing' what's happening in the engine, and the car's computer is getting confused.

Thanks for the tip! Loss of power...hmmm, now that you mention it, yeah, it feels a bit sluggish at times. So, if it IS the knock sensor, is it something I could fix myself, or am I better off taking it to a workshop? I'm not exactly a master mechanic, more like a enthusiastic beginner, haha.

Given the potential for misdiagnosis and the possibility of damaging something further if you're not familiar with the system, I'd strongly recommend taking it to a trusted mechanic. The defective cable or plug connection of the component is the likely cause. Think of it like performing surgery on yourself – you could try it, but the chances of a successful and safe outcome are much higher with a professional. They can properly diagnose the issue and replace the sensor if needed.

Okay, you've convinced me! I'll book an appointment with my local mechanic. Turns out it was the knock sensor and the cable, just like you said! They replaced it, and the total bill came to about 95€. Thanks a bunch for your help! I really appreciate it.