B1440

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Schematic:

CIRCUIT DESCRIPTION
Class 2 communications will not start until the vehicle systems on power mode has been identified. Three discrete wires from the ignition switch contacts are monitored by the Body Control Module (BCM) in order to determine the present power mode (ignition switch position). The BCM communicates the system power mode to all Class 2 modules on the Class 2 bus.

CONDITIONS FOR RUNNING THE DTC
The Body Control Module must be powered.

CONDITIONS FOR SETTING THE DTC
One of the three monitored ignition switch circuits has malfunctioned.

ACTION TAKEN WHEN THE DTC SETS
The BCM implements default actions for each ignition switch position when faults are detected.

CONDITIONS FOR CLEARING THE MIL/DTC
The power moding malfunction must be corrected.

DIAGNOSTIC AIDS
^ The following may cause an intermittent:
- Damaged terminal
- Backed out terminal
- Poor terminal tension
- Chafed wire
- Broken wire inside the insulation
^ When diagnosing for an intermittent short or an open, manipulate the wire harness while watching the test equipment for changes.