▶ With such a huge range of diagnostic equipment available, it is easy to overlook the humble and inexpensive multimeter. Being a measuring device only, it cannot damage software. To use a multimeter successfully, in many cases, you will need data. For example, if testing the serviceability of a particular sensor before buying a new one, you will need seek out the voltage/hertz/ohms specification, as well as which connector on the sensor you need to use. Advanced diagnostic equipment might provide some, if not all, of this information but, if you only have basic hardware, you might need extra assistance – model-specific internet forums might help, although be wary of the authenticity of information supplied by ‘armchair experts’, unless it comes from a credible source.
CM published a two-part guide to using multimeters in February and March 2016, while the June 2017 issue contains additional information on how to test sensors.