[cheshired5]

If you've had a detergent in the fuel tank, it's feasible that debris may have been dislodged and clogged the filter.
Unless you know for certain that the fuel filter is free flowing, I wouldn't rule out anything.

I would strongly recommend using Volvo Dice and Vida software to give you accurate codes along with explanations of symptoms and potential remedies.

Vida can also give live information on actuators and remotely activate them to aid troubleshooting.