Having access to accurate information when you are diagnosing a problem with an electronic system is absolutely essential if you are to be able to make the best possible progress and correct whatever is causing the problem.  Increasingly for the modern mechanic, equipment such as the Fluke 87-5 Digital Multimeter with Thermometer is becoming more important in providing the kind of detailed information that is needed to deal with modern engine management systems and determine exactly what work needs to be carried out.
Fluke are acknowledged as