GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2004 🢒 GTO 🢒 DTC 🢒 DTC 7, 18, 26, or 27

Circuit Description

The powertrain interface module (PIM) receives information from the powertrain control module (PCM) on the Class 2 serial data circuit. If there is a problem with this circuit or the PCM is not communicating, the PIM will detect this lack of information and will set a DTC. Also, if there is a problem with the serial data circuit, performing the Powertrain OBD System Check will lead you to the Data Link Connector Diagnosis.

Conditions for Running the DTC
    • The ignition switch is ON.
    • The ignition voltage is between 5-17 volts.

Conditions for Setting the DTC

The PIM does not receive any serial data communication from the PCM for greater than 5 seconds.

Action Taken When the DTC Sets
    • The PIM will display the DTC only when current.
    • The Check Powertrain MIL will not be activated.

Conditions for Clearing the DTC
    • A Last Test Failed (current DTC) clears, after the ignition has been cycled and the PIM receives serial data from the PCM.
    • Use Tech 2 to clear the DTC.

Diagnostic Aids

The following problems may cause this DTC to set:

    • Poor connections/terminal tension at the PCM.
    • Poor connections/terminal tension at the PIM.

Test Description

The number below refers to the step number on the diagnostic table.

  1. The module which was not communicating on the class 2 serial data circuit may have set Loss of Communication DTCs for those modules that it was monitoring.

Step

Action

Yes

No

Schematic Reference: Data Link Connector Schematics

Connector End View Reference: Data Link Communications Connector End Views

1

Test the following circuits of the module that is not communicating for an open or a short to ground:

    • The battery positive voltage input circuits
    • The battery positive voltage output circuits
    • The ignition voltage input circuits
    • The ignition voltage output circuits
    • The switched battery positive voltage circuits

Refer to the following in Wiring Systems:

    •  Circuit Testing
    •  Wiring Repairs

Did you find and correct the condition?

Go to Step 6

Go to Step 2

2
  1. Turn OFF the ignition.
  2. Test the ground circuits of the module that is not communicating for an open. Refer to the following in Wiring Systems:

Did you find and correct the condition?

Go to Step 6

Go to Step 3

3

Test the class 2 serial data circuits of the module that is not communicating for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Go to Step 4

4

Inspect the harness connectors of the module that is not communicating for poor connections and terminal tension at the following circuits:

    • The battery positive voltage input circuits
    • The battery positive voltage output circuits
    • The ignition voltage input circuits
    • The ignition voltage output circuits
    • The switched battery positive voltage supply circuits
    • The ground circuits
    • The class 2 serial data circuits

Refer to the following in Wiring Systems:

    •  Connector Repairs

Did you find and correct the condition?

Go to Step 6

Go to Step 5

5

Important: Perform the programming or set up procedure for the module, if required.

Replace the module that is not communicating. Refer to the appropriate section for the applicable replacement procedure.

Did you complete the replacement?

Go to Step 6

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6

  1. Install a scan tool.
  2. Turn ON the ignition with the engine OFF.
  3. Select the Display DTCs function for the module which was not communicating.

Does the scan tool display any DTCs which do not begin with a "U"?

Go to Diagnostic Starting Point - Data Link Communications for the applicable Diagnostic System Check

Go to Step 7

7

Select the Display DTCs function for the modules which had the Loss of Communications DTC set.

Does the scan tool display any DTCs which do not begin with a "U"?

Go to the applicable section for the Diagnostic System Check

Go to Step 8

8
  1. Use the scan tool in order to clear the DTCs.
  2. Continue diagnosing or clearing the DTCs until all the modules have been diagnosed and all the DTCs have been cleared.

Did you complete the action?

Go Diagnostic Starting Point - Data Link Communications

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