Instrument Cluster Description and Operation: Tachometer
WARNING: This page is about a different car, the 2007 Pontiac G5 Pursuit, 2007 Pontiac G5, and 2007 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The instrument panel cluster (IPC) displays the engine speed as determined by the powertrain control module (PCM)/engine control module (ECM). The IPC receives a GMLAN message from the body control module (BCM) indicating the engine speed. The tachometer will default to 0 RPM if:
- The PCM detects a malfunction in the engine speed sensor circuit.
- The BCM detects a loss of GMLAN communications with the PCM/ECM.
- The IPC detects a loss of GMLAN communications with the BCM.