P1631

DTC P1631

Diagnostic Instructions

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

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P1631

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Theft Deterrent Fuel Enable Signal Not Correct

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 ACCESSORY or RUN position.

Conditions for Setting the DTC

The ECM receives an incorrect fuel enable password from the RCDLR.

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 correct fuel enable password is received.

* A history DTC will be cleared after 40 malfunction-free ignition cycles.

Reference Information

Schematic Reference

Immobilizer Schematics Immobilizer Schematics

Connector End View Reference

Component Connector End Views 5 Bow Lowered Switch (CM7)

Description and Operation

Immobilizer Description and Operation Immobilizer

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

Perform the 10-Minute Immobilizer Relearn procedure. Refer to Immobilizer System Component Programming Programming and Relearning. 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 Verification Tests after completing the diagnostic procedure.

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