S60 automatic transmission shifting issues

Whoa, that sounds familiar! I had similar issues with my S60. Is it possible that it's related to undervoltage? I had this problem when my battery was getting old. Have you checked your car's voltage recently? I'm not an expert, but...

Undervoltage, huh? That's interesting. I haven't checked that. How exactly does undervoltage cause transmission problems? What were your symptoms when you had the issue?

Okay, so when my battery was on its way out, the car's computer started acting weird, and that messed with the transmission control. I saw the same lights and shifting problems you described. I really recommend checking your battery and electrical system. Otherwise, it's probably time to visit a workshop, just in case.

Thanks for the tip! I had the car checked, and it turns out, the automatic transmission oil was worn, likely due to undervoltage. Had to replace it, cost me 240€, but now it's shifting smoothly again! Appreciate the help!