Instrument Panel Cluster (IPC) Description and Operation: Tachometer
WARNING: This page is about a different car, the 2003 Saturn Vue. 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 BCM via a class 2 message. The ECM determines the engine speed and sends a CAN 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 CAN communications with the ECM.
- The IPC detects a loss of class 2 communications with the BCM.