My car has an intermittent fault that cannot be fixed. It has been to the garage so many times now and they cannot find the fault.
I figure there is no point putting more effort into trying to fix the problem, the car works fine - the mechanics have reassured me the car works fine, but occassionally the engine lights come on.
Now after the car goes to the mechanics the lights will stay off for a week or so. I bought a cheap Bluetooth OBD device, but when I use this to reset the codes, the lights will be on within a few minutes.
What could be the differences between the mechanics OBD device and mine? What would I need to look for to find an OBD device that could work as well as the mechanics?