Tachometer: Description and Operation

Tachometer

The tachometer (part of the LCD Display) is controlled by the CPU in the gauge assembly. The CPU receives a pulsing input from the ECM through the BLU wire (Cavity A19). The frequency and duration of these input pulses are measured by the CPU. The CPU controls the LCD Display to turn on the correct number of segments to indicate the engine speed.

Refer to the Gauges System for specific tests or troubleshooting procedures.