Ascender 2WD L6-4.2L (2003)
Body Control Module: Testing and Inspection
Initial Inspection and Diagnostic Overview
Diagnostic Information and Procedures
Diagnostic Starting Point - Body Control System
Begin the diagnosis of the body control system by performing the diagnostic system check for the system in which the customer concern is apparent. The
diagnostic system check will direct you to the correct procedure for diagnosing the system and where the procedure is located.
Diagnostic Trouble Code Descriptions
For information regarding B, C, P, U and Manufacturer Code Descriptions - See: Computers and Control Systems/Testing and Inspection/Diagnostic
Trouble Code Descriptions
Diagnostic Trouble Code Tests and Associated Procedures
For information regarding diagnosis of all B, C, P, U and Manufacturer Codes - See: Computers and Control Systems/Testing and Inspection/Diagnostic
Trouble Code Tests and Associated Procedures
Symptom-Based Diagnosis
Symptoms - Body Control System
Important: Review the system operation in order to familiarize yourself with the system functions. Refer to Body Control System Description and
Operation.
Visual/Physical Inspection
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Inspect for aftermarket devices which could affect the operation of the body control system.
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Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions.Refer to Diagnostic Aids for Circuit Testing amd Wiring Repair
procedures..
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:
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Power Mode Mismatch
See: Symptom Related Diagnostic Procedures/Power Mode Mismatch
Power Mode Mismatch
Power Mode Mismatch
Circuit Description
Normal vehicle class 2 communications and module operations will not begin until the system power mode has been identified. Discrete wires from the
ignition switch contacts are monitored by the power mode master (PMM) module in order to determine the correct power mode. The PMM
communicates the system power mode to all class 2 modules on the class 2 serial data line. Refer to Body Control System Description and Operation to
identify which module is the PMM and the applicable power mode look up table.