Instrument Cluster Description and Operation: Tachometer

The instrument panel cluster (IPC) displays the engine speed as determined by the engine control module (ECM). The IPC receive serial data messages from the ECM indicating the engine speed. The tachometer will default to 0 RPM if:

• The ECM detects a malfunction in the engine speed sensor circuit.
• The IPC detects a loss of serial data communications with the ECM.