S60 high fuel consumption

Sounds familiar! I had similar symptoms with my S60. Have you checked the throttle position sensor? That was a major culprit for me. Is your acceleration a bit jerky?

Throttle position sensor? I haven't checked that yet. Where is it located, and can I easily test it myself?

Yeah, mine was acting up similarly. I'm not super technical, and I got frustrated. I took it to a workshop, and they confirmed it was a defective accelerator pedal module. Cost me around 205€ to sort it. Best money I ever spent!

Thanks! I'll take it to a local mechanic. The bill ended up being 205€, as you predicted, so thank you, you saved me a lot of time!