We’ve tested 8 OBD readers – watch the video, read the test

OBD readers have become an essential part of the home mechanic’s toolkit, with the ability to read engine fault codes crucial to diagnosing and repairing modern cars and vans.

This handheld diagnostic computer, which communicates with your car’s brain to diagnose fault codes, among other things – is the fastest way to troubleshoot a problem. Without one, you'll have to visit a garage to have the fault code identified for you – and with hourly labour rates at independent garages averaging around £50, that's something none of us wants to do. Pair an OBD fault code reader with our new online guide, Haynes AutoFix, and you will be able to diagnose and repair most common faults and electrical issues at home with simple tools.

Technical Editor, Martynn Randall has been with Haynes for 27 years and has written more than 60 Haynes Manuals.