Circuit Description

WARNING: This page is about a different car, the 2002 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.

The IPC and the body control module BCM communicate over an exclusive serial peripheral interface, SPI. The BCM and the IPC are the only two modules that use the SPI serial data circuit implemented on the vehicle. The IPC receives information from the BCM over the SPI serial data "A" circuit. The BCM transmits information to the IPC in order to control various indicators, the engine coolant temperature gage, speedometer, Tachometer and the fuel gage. The BCM receives data from the IPC's over the SPI serial data "B" circuit. The IPC transmits information such as tachometer active status, speedometer active status, and invalid data received messages. The BCM synchronizes the data signals by toggling the SPI serial data clock circuit to ground. The IPC can not hold any Class 2 DTC's, all Class 2 DTC setting and holding is handled in the BCM.