Tachometer: Description and Operation

TACHOMETER

The IPC displays the engine speed as determined by the ECM/PCM. The IPC receives a GMLAN message from the ECM/PCM indicating the engine speed. The tachometer will default to 0 rpm if:
- The ECM/PCM detects a malfunction in the engine speed sensor circuit.
- The IPC detects a loss of GMLAN communications with the ECM/PCM.