GM Service Manual Online
For 1990-2009 cars only

Refer to Theft Deterrent System Schematics in Theft Deterrent System.

Circuit Description

The Vehicle Theft Deterrent (VTD) module is located within the steering column. If the VTD module has been replaced, the password must be relearned using approved Techline diagnostic equipment. If the PCM is replaced, the replacement PCM should learn the password within a few seconds after the ignition is turned ON. DTC P1630 is an information code indicating that the PCM is ready to learn the VTD password. The engine will start and continue to run with DTC P1630 set. Refer to Theft Deterrent System Schematics for further information regarding the VTD system.

Conditions for Running the DTC

    • The VTD system has allowed fuel delivery.
    • The PCM is in the theft deterrent password learn mode.

Conditions for Setting the DTC

The PCM remains in theft deterrent password learn mode for greater than 2 seconds.

Action Taken When the DTC Sets

    • The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
    • The PCM will store conditions which were present when the DTC set as Fail Records data only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

    • A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids

A new replacement PCM will be in a functional state to learn the password from theVTD module. If the VTD module is replaced, the PCM must be placed in password learning mode to relearn a new password. Once learned, the password becomes permanent information that remains with the vehicle. The loss of PCM battery or ignition voltage will not affect the programmed password information.

Refer to Diagnostic Starting Point for information concerning the password learning procedure.

DTC P1630 - Theft Deterrent System PCM in Password Learn Mode

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic System Check performed?

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Go to Diagnostic Starting Point in Theft Deterrent

Go to Powertrain On Board Diagnostic (OBD) System Check