Engine Coolant Temperature Gauge

Instrument panel cluster displays engine coolant temperature as determined by Powertrain Control Module (PCM). Body Control Module (BCM) receives a class 2 message from PCM indicating engine coolant temperature. BCM converts engine coolant temperature into a percent gauge deflection. Instrument panel cluster receives a message from BCM via Serial Peripheral Interface (SPI) indicating requested gauge position. Engine coolant temperature gauge defaults to 38°C (100°F) or below if PCM detects a malfunction in engine coolant temperature sensor circuit, BCM detects a loss of class 2 communications with PCM, or instrument panel cluster detects a loss of SPI communications with BCM.