I have bought a cheap BT ELM327 device, and ran it with a (very!)dated Nokia cellphone, which can hold an app called OBDScope (avaliable on OBDScope - The OBD tool for Symbian ), for Symbian S60 smartphones. For a common DIYier, it may give enough information, but I'm missing some custom PIDs for my Prius. Any thread on that already?