Description & Operation: Tachometer

Instrument panel cluster displays engine speed based on information from Powertrain Control Module (PCM). PCM converts data from engine speed sensor to a 2 pulses/engine revolution signal. Instrument panel cluster uses engine speed signal circuit of 2 pulses/engine revolution from PCM in order to calculate engine speed. Tachometer defaults to zero RPM if a malfunction in engine speed signal circuit of 2 pulses/engine revolution exists or if BCM sends or receives invalid data with instrument panel cluster via Serial Peripheral Interface (SPI).