Instrument Cluster Description and Operation: Tachometer
WARNING: This page is about a different car, the 2009 Pontiac Torrent and 2009 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
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.