P1631

DTC P1631

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptor
DTC P1631
- 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 (Connector Views)
Description and Operation

Immobilizer Description and Operation (Immobilizer Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) 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 (Programming and Relearning) for ECM replacement, setup and programming