P1631

DTC P1631

Circuit Description

The theft deterrent module (TDM) produces the theft deterrent fuel enable password when the ignition is ON and the proper transponder key value is detected. The powertrain control module (PCM) monitors the fuel enable password. If the proper password is present on the serial data circuit, the PCM enables the fuel delivery in order to allow the engine to start. If the PCM detects an incorrect password, vehicle theft deterrent (VTD) system failure, or attempted vehicle theft, DTC P1631 is set. During this condition, the PCM disables fuel delivery, NOT allowing the engine to start.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1631 Theft Deterrent Fuel Enable Signal Not Correct

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The PCM detects an incorrect password from the TDM.

Action Taken When the DTC Sets

* The vehicle will not start.
* The PCM sends a serial data message to the body control module (BCM) to 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

DTC P1631 indicates that the PCM has detected an incorrect fuel enable password from the TDM. This condition can occur if an incorrect key is being used when attempting to start the vehicle or if the TDM has been replaced and the PCM password learn function has not been enabled.

Test Description

Step 1 - Step 6:

The numbers below refer to the step numbers on the diagnostic table.
2. This step verifies if the condition for setting DTC B3060 is present.
3. To set this code, the password that the PCM has learned does not agree with the password being received from the TDM. This condition can occur if the TDM has been replaced and the programming theft deterrent system components procedure has not been performed.
5. If the PCM resets the DTC after the programming theft deterrent system components procedure has been performed, the theft deterrent control module is malfunctioning.