Combination Meter: Tachometer
CAUTION:
Do not operate the engine with the pointer of the tachometer in the red zone. In this range, fuel injection will be cut by the engine control module to protect the engine from over-revving. The engine will resume running normally after the engine speed is reduced below the red zone.
The tachometer drive circuit is connected to the engine speed sensing circuit in the engine control module; it shows the engine speed in thousands of revolutions per minute. When the engine speed changes (increases or decreases), the circuit voltage correspondingly changes which changes the tachometer drive coil's magnetic force. The tachometer needle then moves in accordance with the change in engine speed. See Fig 1 .