P1631

DTC P1631

Circuit Description

The remote control door lock receiver (RCDLR) sends the fuel enable password to the engine control module (ECM) via the serial data circuit. The ECM verifies the fuel enable password received matches the password stored in memory. If the fuel continue password is correct, the ECM enables the starting and fuel delivery systems. When replacing a ECM with a GM SPO replacement part, the new ECM will learn the incoming fuel enable password immediately upon request.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The ECM receives an incorrect password from the remote control door lock receiver (RCDLR).

Action Taken When the DTC Sets

^ The vehicle will not start.
^ The instrument panel cluster (IPC) will illuminate the SECURITY indicator.
^ The PCM will not illuminate the malfunction indicator lamp (MIL).

Conditions for Clearing the MIL/DTC

^ A History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.

Diagnostic Aids

A GM SPO replacement ECM is in a functional state to learn the password from the remote control door lock receiver (RCDLR). If the RCDLR is replaced, the ECM must be placed in password learning mode to relearn the new password. Once learned, the password becomes permanent information that remains in the ECM. The loss of ECM battery or ignition voltage does not affect the programmed password information. Refer to Programming Theft Deterrent System Components.