Operation CHARM: Car repair manuals for everyone.

Tachometer

The tachometer is an analog gauge that is located in the instrument cluster. The PCM/VCM sends RPM pulses to the instrument cluster on a designated circuit. These pulses may be measured in Hertz (Hz) using a Digital Multimeter (DMM) on the AC scale. The instrument cluster will interpret the RPM pulses in order to appropriately display the engine RPM on the tachometer.