Sometimes we become so caught up in leading-edge diagnostic technology that we forget that a professional-grade digital volt-ohm meter (DVOM) or digital multimeter (DMM) is a vital tool in any technician’s diagnostic arsenal. The DMM shines in many diagnostic situations simply because it requires little set-up time, is compact and extremely durable, and provides real-time electrical values on various sensor and actuator circuits found in modern electronic vehicles.

The diagnostic capacity of this DMM is complemented by a tachometer lead, an infrared testing probe, a pressure and vacuum transducer, and a low-amperage probe. Maintaining an inventory of spare fuses, batteries, test leads and test probes helps speed the diagnostic process.

The Professional DMM
Before buying a DMM, it’s good to know which features are essential for diagnosing really tough electrical and electronic problems. To illustrate, a professional-grade DMM is built with a 10 meg-ohm impedance for measuring very small voltage levels. Without this impedance, the meter essentially shorts the circuit to ground and provides a very inaccurate voltage reading. While cheaper DMMs can be used for testing comm...