Circuit Description

Body Control Module (BCM) is the power mode master responsible for sending ignition switch position information on class 2 serial data circuit. Three separate wires from ignition switch contacts are monitored by BCM determining present power mode. BCM communicates this power mode information to all class 2 modules on class 2 serial data circuit. To aid in identifying circuits which represent BCM power mode data, see power mode master chart. See Figure.

When DTC B1440 sets, BCM implements default actions for each ignition switch position as faults are detected.

A current DTC B1440 will clear when BCM no longer detects a power mode malfunction. A history DTC clears after 100 malfunction free ignition cycles.