GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2003 🢒 Grand Prix 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 DTC P1629

Circuit Description

The theft deterrent control module produces the theft deterrent fuel enable signal when ignition is ON and the proper transponder key value is detected. The powertrain control module (PCM) monitors the fuel enable signal during crank. If the proper signal is present the PCM enables the fuel delivery in order to allow the engine to start.

Conditions for Running the DTC

The ignition is the CRANK position.

Conditions for Setting the DTC

The powertrain control module (PCM) detects an incorrect password from the theft deterrent control module.

Actions Taken When the DTC Sets
    • The vehicle will not start.
    • The theft deterrent control module will not illuminate the SECURITY indicator.
    • The PCM will not illuminate the malfunction indicator lamp (MIL).
    • The PCM will store conditions which were present when the DTC set as failure records data only. This information will not be stored as freeze frame data.

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

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

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Verifies the condition for setting code P1626 or P1629 is current.

    2.

  2. Verifies the condition for setting code B2955 or B2960 is current.

    3.

  3. Verifies the theft deterrent control module has sent the fuel enable password.

    4.

  4. Test the pulled high voltage is present at the theft deterrent control module.

    5.

  5. Test the frequency is present at the powertrain control module (PCM).

    6.

  6. If the theft deterrent control module is replaced the new module has to be programmed.

    7.

  7. If the PCM is replaced the new module has to learn the theft deterrent control module fuel enable password.

Step

Action

Value(s)

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

Is DTC P1626 or P1629 set as a current code?

--

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

3

Is DTC B2955 or B2960 set as a current code?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 4

4

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the fuel enable parameter in the Vehicle Theft Deterrent, Inputs data list.

Does the scan tool indicate that the theft deterrent fuel enable parameter is enable?

--

Go to Step 5

Go to Step 8

5

  1. Turn OFF the ignition.
  2. Disconnect the theft deterrent control module connector located at the base of the steering column.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the fuel enable control circuit at the vehicle harness connector to a good ground.

Does the voltage measure near the specified value?

5 V

Go to Step 6

Go to Step 7

6

  1. Turn OFF the ignition.
  2. Reconnect the theft deterrent control module.
  3. Disconnect the powertrain control module (PCM).
  4. Turn ON the ignition, with the engine OFF.
  5. With the J 39200 select the DC mV scale, and press the Hz button.
  6. Measure the frequency from the fuel enable control circuit at the PCM harness connector to a good ground.

Does the frequency measure near the specified value?

50 Hz

Go to Step 12

Go to Step 8

7

Test the fuel enable control circuit for an open, short to battery voltage or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

8

Inspect for poor connections at the harness connector of the theft deterrent control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 10

9

Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

10

Important: If a 10 Minute or 30 Minute Re-Learn Procedure is perform, 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 theft deterrent control module . Refer to Theft Deterrent Module Replacement .
  2. Perform the Programming Theft Deterrent System Components procedure. Refer to Programming Theft Deterrent System Components .

Did you complete the replacement?

--

Go to Step 12

-

11

Important: The replacement powertrain control module (PCM) must learn the theft deterrent control module fuel enable password. Refer to Programming Theft Deterrent System Components .

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 3.1L or Powertrain Control Module Replacement in Engine Controls - 3.8L.

Did you complete the replacement?

--

Go to Step 12

--

12
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running in the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK