Fuel Gauge

Instrument panel cluster displays fuel level as determined by the Powertrain Control Module (PCM). Body Control Module (BCM) receives a class 2 message from PCM indicating fuel level percent. BCM converts fuel level percent into a percent gauge deflection. Instrument panel cluster receives a message from BCM via Serial Peripheral Interface (SPI) indicating requested gauge position. Fuel gauge defaults to "E" (empty) if PCM detects a malfunction in fuel sending unit circuit, BCM detects a loss of class 2 communications with PCM or instrument panel cluster detects a loss of SPI communications with BCM. When fuel level is less than a pre-determined value, low fuel indicator illuminates.