I've got an ELM 327
I've got an ELM 327 off a well know auction site which cost about £12. Connects via bluetooth to mobile. Installed torque lite free app on phone. Reads faults and links to a website with fault descriptions, can clear faults too and does data logging.
Works well.
Doesn't that only work for certain cars? I know it won't work on my Focus ST without some wiring modifications...
You shouldn't need to modify anything. The ST has a standard ODBII connection which an ELM327 will fit
Apparently not. There is a long running group buy where members are paying £25 for the modded ELM327.
Apparently some wires need changing...
Sounds like bunkum to me. As far as I understand, The OBD specification and connector pinout is an international standard. The only issue with the "jack of all trades" code readers is that they can't pick up some vehicle-specific fault codes that may exist in various other control units throughout the car rather than the ECU itself.