Sierra Denali AWD V8-6.0L VIN N (2004)
Tachometer: Description and Operation
TACHOMETER
The IPC displays the engine speed on the analog tachometer based on the engine speed signal from the PCM. The IPC uses the engine speed signal
circuit - 2 pulses/engine revolution - 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.