GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The body control module (BCM) sends fuel enable password to the powertrain control module (PCM) via the serial data circuit when the ignition is ON and the BCM has read a learned transponder value from the key. The PCM verifies the fuel enable password to the fuel enable password stored in memory. If the fuel enable password is correct, the PCM enables starting and fuel delivery systems. When replacing a PCM with a GM SPO replacement part, the new PCM will learn the incoming fuel enable password immediately upon receipt.

DTC Descriptor

This diagnostic procedure supports the following DTC.

DTC P1626 Theft Deterrent Fuel Enable Signal Lost.

Conditions for Running the DTC

The ignition is switched to CRANK then to ON.

Conditions for Setting the DTC

The PCM has either lost or not received the fuel enable password from the BCM.

Action Taken When the DTC Sets

    • The vehicle will not start.
    • The drivers information center (DIC) displays Starting Disabled Due To Theft message.
    • The PCM will not illuminate the malfunction indicator lamp (MIL).

Conditions for Clearing the MIL/DTC

    • The PCM clears the current status of the DTC when it receives a valid fuel enable password from the BCM.
    • 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

Refer to Testing for Intermittent Conditions and Poor Connections and Testing for Electrical Intermittents in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. To set this code, the password that the PCM has learned does not agree with the password being received from the BCM. This condition can occur if the BCM has been replaced and the programming theft deterrent system components procedure has not been performed.

  2. If the PCM resets the DTC after the programming theft deterrent system components procedure has been performed, the BCM is malfunctioning.

Step

Action

Yes

No

Schematic Reference: Theft Deterrent System Schematics

Connector End View Reference: Theft Deterrent System Connector End Views

1

Did you perform the Theft Deterrent Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Theft Deterrent

2

Important: If a 10 Minute or 30 Minute Re-Learn Procedure is performed, all keys not learned at that time will be erased and will not be recognized. Perform the Adding Keys procedure on all keys or instruct the customer how to perform the Adding Keys procedure. Refer to Adding Keys .

Perform the Programming Theft Deterrent System Components procedure. Refer to Programming Theft Deterrent System Components .

Is the procedure complete?

Go to Step 3

--

3

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 4

System OK

4

Important: If a 10 Minute or 30 Minute Re-Learn Procedure is performed, all keys not learned at that time will be erased and will not be recognized. Perform the Adding Keys procedure on all keys or instruct the customer how to perform the Adding Keys procedure. Refer to Adding Keys .

  1. Replace the BCM. Refer to Body Control Module Replacement .
  2. Perform the programming theft deterrent system components procedure. Refer Programming Theft Deterrent System Components .

Is the replacement complete?

Go to Step 5

--

5

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK