GM Service Manual Online
For 1990-2009 cars only

Circuit Description

This diagnostic test checks for the Enable Password Learning Flag indicating the PCM is in learn password mode. This mode allows the PCM to learn the password from the Vehicle Theft Deterrent controller (IPC) at assembly or when being serviced. The password needs to be learned whenever the PCM or the IPC is replaced.

Conditions for Running the DTC

VATS is enabled.

Conditions for Setting the DTC

When the Enable Learning Flag is set.

Action Taken When the DTC Sets

    •  The Malfunction Indicator Lamp (MIL) will not illuminate.
    •  No message will be displayed.

Conditions for Clearing the DTC

    •  A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test.
    •  A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.
    • Use a scan tool to clear DTCs.
    • Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation.

Diagnostic Aids

The PCM in learn mode is a DTC for the vehicle at the assembly plant, dealership and outside garage personnel as an indication that the learn mode is enabled. This means the PCM is now ready to learn a new password. Refer to Programming Replacement Keys, Ignition Cylinder, or Powertrain Control Module in Theft Deterrent for further diagnosis and programing procedures.

Step

Action

Value(s)

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

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Go to Diagnostic Aids

Go to Powertrain On Board Diagnostic (OBD) System Check