If dpf regen is suspected culprit in your predicament, a ELM327 reader and simple phone app will display both the exact oil level (in mm) and DPF soot (grams), as well as the DPF regen, which may take up to 20 minutes.
https://www.volvoforums.org.uk/showt...=296736&page=2
ianmac22 - this app will not work on your SPA platform, though (no DPF soot nor oil level available in the new V90).