Express 3500 V8-6.0L VIN U (2004)
Accessory Delay Module: Initial Inspection and Diagnostic Overview
Diagnostic Starting Point
DIAGNOSTIC STARTING POINT
Review the Retained Accessory Power (RAP) Description and Operation before you begin the system diagnosis. Reviewing the Description and
Operation
information will help you determine if the condition described by the customer is normal operation.
Begin the system diagnosis with the Diagnostic System Check - Accessory Delay Module. The Diagnostic System Check will provide the following
information:
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The identification of the control modules which command the system
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The ability of the control modules to communicate through the serial data circuit
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The identification of any stored diagnostic trouble codes (DTCs) and their status
The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.
Diagnostic System Check
DIAGNOSTIC SYSTEM CHECK
TEST DESCRIPTION
Step 1