Definitions for "Scan Tool"
A device that interfaces and communicates with the on-board computer on the vehicle. Engine RPM information can be obtained without a tachometer with this tool. Each automobile or truck manufacturer will have their own specialized scan-tool. There are aftermarket scan-tools also available; however, they often lack many of the crucial functions required to diagnose today's complex vehicles. GM's scan tool, shown below, is called the Tech-2.
an essential piece of diagnostic equipment
a small handheld computer that connects to the vehicle onboard computer systems
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a MUST for tuning your car