K 2500 Yukon XL 4WD V8-8.1L VIN G (2001)
Tachometer: Description and Operation
The IPC displays the engine speed based on the engine speed signal from the PCM. The IPC receives the engine speed signal from the PCM via a
discreet wire. 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 (2 pulses/engine revolution) exists.