Vibe FWD L4-2.4L (2009)
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 (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/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.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to Data Link Communications Description and
Operation (See: Description and Operation).
Visual/Physical Inspection
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Inspect for aftermarket devices which could affect the operation of the systems. Refer to Checking Aftermarket Accessories (See: Testing and
Inspection/Component Tests and General Diagnostics).
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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 (See: Scan Tool Does Not Power Up)
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Scan Tool Does Not Communicate with Class 2 Device (See: Scan Tool Does Not Communicate with Class 2 Device)
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Scan Tool Does Not Communicate with High Speed GMLAN Device (See: Scan Tool Does Not Communicate with High Speed GMLAN
Device)
Scan Tool Does Not Communicate with Class 2 Device
Scan Tool Does Not Communicate with Class 2 Device
Circuit Description
Modules connected to the serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and
commands are exchanged among the modules. Connecting a scan tool to the data link connector (DLC) allows communication with the modules for
diagnostic purposes.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
3. A partial malfunction in the low speed GMLAN serial data circuit uses a different procedure from a total malfunction of the serial data circuit. The
following modules communicate on the serial data circuit.
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Communication interface module (OnStar(R))
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Radio
5. DLC terminals 2 and 5 provide the connection to the serial data circuit and the signal ground circuit respectively.
7. A poor connection at splice pack S232 will cause this condition but will not set a DTC.
8. An open in the class 2 serial data circuit between the DLC and splice pack S232 will prevent the scan tool from communicating with any module on
the class 2 network. This condition will not set a DTC.
