GM Service Manual Online
For 1990-2009 cars only

DTC Descriptor

DTC P1632 : Theft Deterrent Fuel Disable Signal Received

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Circuit/System Description

The theft deterrent module (TDM) sends the fuel enable password to the engine control module (ECM) via the serial data circuit. If the password sent by the TDM equals the password stored in the ECM, the ECM will allow vehicle starting.

Conditions for Running the DTC

Ignition is in the RUN position.

Conditions for Setting the DTC

The fuel enable password is valid but does not pass authentication in the ECM.

Action Taken When the DTC Sets

    • The security indicator will illuminate.
    • Vehicle starting will be disabled.

Conditions for Clearing the DTC

    • A current DTC P1632 will be when a valid password is received.
    • A history DTC will be cleared after 40 malfunction free ignition cycles or when a scan tool is used to clear DTCs.

Reference Information

Schematic Reference

Theft Deterrent System Schematics

Connector End View Reference

Theft Deterrent System Connector End Views

Description and Operation

Vehicle Theft Deterrent (VTD) Description and Operation

Electrical Information Reference

    •  Testing for Intermittent Conditions and Poor Connections
    •  Circuit Testing
    •  Wiring Repairs
    •  Connector Repairs

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

Important: Because of normal system communications between the TDM and ECM, any theft deterrent B-codes must be diagnosed prior to the diagnosis of P-codes.

Perform the Programming Theft Deterrent System Components procedure. Refer to Programming Theft Deterrent System Components . The ECM should successfully complete the password learn and the vehicle should start.

If the ECM does not complete the learn or vehicle starting remains disabled, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming.