Operation CHARM: Car repair manuals for everyone.

Tachometer

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 PC detects a loss of class 2 communications with the PCM.