Instrument Cluster Description and Operation: Tachometer

The IPC displays the engine speed as determined by the ECM. The ECM determines the engine speed and sends a serial data message to the BCM indicating the engine speed. The tachometer will default to 0 RPM if:

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