Tachometer

The IPC displays the engine speed based on the information from the PCM. The PCM converts the data from the engine speed sensor to a 2 pulses/engine revolution signal. The IPC uses the engine speed signal circuit (2 pulses/engine revolution) from the PCM in order to calculate the engine speed. If the IPC detects a malfunction in the engine speed signal circuit, the IPC uses the class 2 message from the PCM indicating the engine speed.