to identify the operators desired power mode and activate specific discrete signals, and serial data messages for the operation of many different
subsystems as necessary. Other modules which have switched voltage inputs may operate in a default mode if the PMM serial data message does not
match what the individual module can see from its own connections.
The PMM will activate relays and other direct outputs of the PMM as needed according to the calculated power mode. Several relays controlled by
the BCM are switched ignition voltage outputs the are pass through circuits within the BCM directly from the ignition switch. If these circuits short
to ground, the fuse to the ignition switch will open.
Conditions for Running the DTC
Ignition switch is in the OFF or ACC positions.
Ignition switch is in the START position.
Conditions for Setting the DTC
Ignition 1 voltage circuit is shorted to voltage for more than 2 seconds.
* Ignition 1 voltage circuit is open for more than 2 seconds.
* Ignition 1 voltage, accessory voltage, or off/run/crank voltage circuit shorted to ground.
* Battery positive voltage circuit of the ignition switch open or shorted to ground.
* Run crank relay coil control circuit open (including relay coil and ground).
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.
* A short to ground in the accessory wakeup serial data circuit will cause an open fuse to the ignition switch. DTC U1814 should be current.
* A short to ground in the run/crank ignition 1 voltage circuit of the run crank relay will cause an open fuse to the ignition switch. DTC B1428
should be current.
* The power modes and controls are determined using BCM logic. Comparing the Body Control Module Power Mode data display parameters
listed in Circuit/System Verification will determine if there is a power mode fault.
* Body Control System Schematics (See: Body and Frame/Body Control Systems/Diagrams/Electrical Diagrams)
* Power Distribution Schematics (See: Diagrams/Electrical Diagrams/Starting and Charging/Power and Ground Distribution/System
Diagram/Power Distribution Schematics)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Power Mode Description and Operation (See: Power and Ground Distribution/Description and Operation/Power Mode Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information