GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2007 🢒 Vibe - FWD 🢒 Power and Signal Distribution 🢒 Data Communications 🢒 Scan Tool Does Not Communicate with Class 2 Device

Circuit Description

Modules connected to the class 2 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.

  1. A partial malfunction in the class 2 serial data circuit uses a different procedure from a total malfunction of the class 2 serial data circuit. The following modules communicate on the class 2 serial data circuit.

    2. • Communication interface module (OnStar®)
    • Electronic brake control module (EBCM)
    • Inflatable restraint sensing and diagnostic module (SDM)
    • Instrument panel cluster (IPC)
    • Radio

  2. DLC terminals 2 and 5 provide the connection to the class 2 serial data circuit and the signal ground circuit respectively.

    3.

  3. A poor connection at splice pack S232 will cause this condition but will not set a DTC.

    4.

  4. 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.

Step

Action

Yes

No

Schematic Reference: Data Communication Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn ON the ignition, with the engine OFF.
  2. Perform the Vehicle DTC Information function on the scan tool under Computer/Integrating Systems menu.

Are any DTC's retrieved from any module?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 3

3

Did the scan tool communicate with any module on the class 2 serial data circuit?

Go to Step 4

Go to Step 5

4

Diagnose the non-communicating module by referring to the appropriate section.

Did you complete the action?

Go to Diagnostic System Check - Vehicle

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5

  1. Turn OFF the ignition.
  2. Disconnect the scan tool from the data link connector (DLC).
  3. Inspect for poor connections at the DLC terminals 2 and 5. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Diagnostic System Check - Vehicle

Go to Step 6

6

Test the DLC ground circuit at terminal 5 for an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Diagnostic System Check - Vehicle

Go to Step 7

7

  1. Disconnect the splice pack S232.
  2. Inspect for poor connections at the splice pack SP205. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Diagnostic System Check - Vehicle

Go to Step 8

8

Repair the class 2 serial data circuit between the DLC and the splice pack S232 for an open. Refer to Circuit Testing and Wiring Repairs .

Did you complete the action?

System OK

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