If concerned with D2 engine just install
Car Scanner Elm OBD2.
App will read error codes and display over 70 parameters of Volvo D2 engine: DPF soot, DPF pressure, coolant temp, engine oil temp, AT temp, EGR error, MAP, MAF, turbo boost, fuel injector corrections, battery state of charge, charging current, etc.
(choose Volvo D2 in "Settings - Connection - Choose connection profile")