Bonneville V8-4.6L VIN Y (2004)
Tachometer: Description and Operation
TACHOMETER
The IPC displays the engine speed based on information from the PCM. The PCM converts the engine speed data to a 2 pulses/engine revolution signal.
The IPC uses the engine speed signal circuit from the PCM in order to calculate the engine speed. The tachometer defaults to 0 rpm if a malfunction in
the engine speed signal circuit exists.