Charging System Indicator

The body control module (BCM) sends a message to the IPC via the serial peripheral interface (SPI) requesting illumination. The IPC illuminates the charging system indicator when the following occurs:
^ The PCM detects that the generator output is less than 11 volts or greater than 16 volts. The BCM receives a class 2 message from the PCM requesting illumination. The also BCM sends a class 2 message to the radio in order to activate an audible warning.
^ The IPC performs the displays test at the start of each ignition cycle as commanded by the BCM. The indicator illuminates for approximately 3 seconds.
^ The PCM determines that the ignition is on, with the engine off or the ignition is in the accessory position. The BCM receives a class 2 message from the PCM requesting illumination.