GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P1632: Theft Deterrent Fuel Disable Signal Received

Circuit/System Description

The remote control door lock receiver (RCDLR) sends the fuel enable password to the engine control module (ECM) via the serial data circuit. If the fuel enable password received from the RCDLR equals the fuel enable 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

A fuel disable signal from the RCDLR is received by 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 will be when a valid fuel enable password is received.
    • A history DTC will be cleared after 40 malfunction-free ignition cycles.

Reference Information

Schematic Reference

Immobilizer Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Immobilizer Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Perform the 10-Minute Immobilizer Relearn procedure. Refer to Immobilizer System Component Programming . 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