Sierra 1500 2WD V6-4.3L (2008)
Information Bus: Symptom Related Diagnostic Procedures
Symptoms - Data Communications
Symptoms - Data Communications
Important: The following steps must be completed before using the symptom tables.
1. Perform the Diagnostic System Check - Vehicle before using the symptom tables in order to verify that all of the following are true:
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There are no DTCs set.
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The control modules can communicate via the serial data links. See: Testing and Inspection/Initial Inspection and Diagnostic
Overview/Diagnostic System Check - Vehicle
2. Review the system operation in order to familiarize yourself with the system functions. Refer to:
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Body Control System Description and Operation
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Data Link Communications Description and Operation
Visual/Physical Inspection
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Inspect for aftermarket devices which could affect the operation of the systems.
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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 Testing for Intermittent Conditions and Poor Connections.
See: Testing and Inspection/Component Tests and General Diagnostics
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:
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Scan Tool Does Not Power Up
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Scan Tool Does Not Communicate with High Speed GMLAN Device
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Scan Tool Does Not Communicate with Low Speed GMLAN Device
Scan Tool Does Not Communicate with High Speed GMLAN Device
Scan Tool Does Not Communicate with High Speed GMLAN Device
Diagnostic Instructions
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Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. See: Testing and Inspection/Initial Inspection and
Diagnostic Overview/Diagnostic System Check - Vehicle
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Review Strategy Based Diagnosis for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
Modules connected to the high speed GMLAN serial data circuits monitor for serial data communications during normal vehicle operation. Operating
information and commands are exchanged among the modules when the ignition switch is in any position other than OFF. The high speed GMLAN serial
data circuits must be operational for the vehicle to start due to body control module (BCM) and engine control module (ECM)/powertrain control
module (PCM) communications. The theft deterrent module and ECM/PCM exchange information using the BCM as the gateway module allowing
