Impreza WRX F4-2.0L DOHC Turbo (2004)
Tachometer: Description and Operation
TACHOMETER
The tachometer drive circuit is connected to the engine speed sensing circuit in the engine control module.
When the engine speed increases or decreases, the voltage of the circuit also increases or decreases, changing the magnetic force of the tachometer drive
coil.
The tachometer needle then moves in accordance with change in the engine speed.
