Throughout the sections of the site you will find a brief description of the system to be tested and a set of techniques to successfully diagnose any faults that you may have. The guides will not be the definitive source but instead will give you a good understanding of what is needed to achieve results.

You may need more system specific information like pin data or a wiring diagram. There are many sources available. A few of which are: Auto Data, Bosh Esi , Alldata and Michel on demand. The later two cover Usa and Asian vehicles. If you can source main dealer information then this will be invaluable when you need specific information about a system or its wiring loom. A quick search on line reveals many sources for Workshop manuals.

 You can have the best diagnostic tool in the world but without either the knowledge to interpret the results or a voltmeter to test and measure results, then the equipment is next to useless to you. An example would be when your equipment reports a lambda sensor fault. How many people have gone out and bought a new lambda sensor only to find out that the same fault is reported once it has been fitted. There are many faults that can lead to this fault being reported, I will go into them in more depth in the relevant section, but the cause could simply be a faulty spark plug or a split breather pipe. This is where the basic diagnostic process comes in to use.

It is far better to feel a sense of achievement  by successfully diagnosing and repairing a fault than spending hundreds of pounds on guess work mechanics where eventually the faulty part will get replaced by a lengthy and expensive process of elimination.