Instrument Panel Cluster (IPC) Description and Operation: Tachometer

WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. 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 PCM. The IPC receives a class 2 message from the PCM indicating the engine speed. The tachometer will default to 0 rpm if:

The PCM detects a malfunction in the engine speed sensor circuit.
The IPC detects a loss of class 2 communications with the PCM.