GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2003 🢒 Grand Prix 🢒 Body and Accessories 🢒 Theft Deterrent 🢒 DTC B2955

Circuit Description

When an ignition key is inserted into the ignition lock cylinder, the transponder embedded in the head of the key is energized by the exciter coils surrounding the ignition lock cylinder. The energized transponder transmits a signal that contains its unique value, which is received by the theft deterrent control module. The theft deterrent control module then compares this value to a value stored in memory (learned key code). If the value is correct the theft deterrent control modules sends the fuel enable signal to the powertrain control module (PCM).

Conditions for Running the DTC

The ignition is ON.

Condition for Setting the DTC

The theft deterrent control module is unable to measure the ignition key transponder value. This may be due to a damaged or missing transponder, a non Passkey III (PK3) key, or a damaged exciter.

Action Taken When the DTC Sets

Important: If the theft deterrent control module is unable to measure the ignition key transponder value for 30 consecutive seconds, after the vehicle has started, the module will enter a fail enable state. The vehicle will not stall or stop running. If the theft deterrent control module is in a fail enable state when the ignition is turned to OFF, it will remain fail enabled until the next time the vehicle is started. If the theft deterrent control module is fail enabled, the PASS-Key®III system is NOT active and the vehicle will start. The theft deterrent control module WILL send its enable signal even if a transponder value is not received. The theft deterrent control module will remain fail enabled until the module measures a valid key transponder value.

    • The theft deterrent control module sends the fuel disable signal to the PCM.
    • The vehicle will not start.
    • The theft deterrent control module flashes the SECURITY indicator.

Conditions for Clearing the MIL/DTC
    •  A history DTC will clear after 100 consecutive fault free ignition cycles.
    • Using a scan tool in order to clear a history DTC.

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. Verifies the condition for setting DTC B2955 is current.

    2.

  2. The key must be a PASS-Key®III transponder key with an operating transponder for the system to work.

    3.

  3. The only method to confirm whether the transponder in the key or the theft deterrent control module is malfunctioning is to try a alternative component in the system. The vehicle was delivered with 2 keys.

    4.

  4. The possibility is unlikely that more than one key will be defective. If all keys do not work, the theft deterrent control module must be malfunctioning.

    5.

  5. If the vehicle has a malfunctioning theft deterrent control module that malfunctioned during an ignition cycle, the system will be "fail enabled" and the vehicle will start for all keys.

    6.

  6. If a new key must be tried, the key must have the proper mechanical cut and the theft deterrent control module must "learn" the transponder value.

    7.

  7. If only one key was available for the vehicle and the replacement key does not work, the theft deterrent control module must be 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 A Diagnostic System Check - Theft Deterrent System?

Go to Step 2

Go to Diagnostic System Check - Theft Deterrent

2

Is DTC B2955 set as a current code?

Go to Step 3

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

3

Inspect the vehicle's key for damage to the molded head and for PK3 embossed on the shank.

Is the head of the key damaged or missing the PK3 embossing?

Go to Step 7

Go to Step 4

4

Are more than one of the vehicles keys available?

Go to Step 5

Go to Step 7

5

  1. Attempt to start the vehicle using all of the vehicle's available keys.
  2. Using a scan tool, observe for any vehicle theft deterrent DTCs.

Do any of the available keys start the vehicle?

Go to Step 6

Go to Step 9

6

Do all of the available keys cause DTC B2955 to set?

Go to Step 9

Go to Step 7

7

  1. Replace the damaged/inoperative/suspect key.
  2. Copy the mechanical cut of the available key on a PASS-Key®III replacement key.
  3. Perform the Adding Keys procedure if a learned master key is available. Refer to Adding Keys . If a learned master key is not available . Refer to Replacing Keys .

Is the replacement completed?

Go to Step 8

--

8

Does the replacement key cause DTC B2955 to set?

Go to Step 9

Go to Step 11

9

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

Did you find and correct the condition?

Go to Step 11

Go to Step 10

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. Refer to Programming Theft Deterrent System Components .

Did you complete the replacement?

Go to Step 11

--

11
  1. Use a scan tool in order to clear the DTCs.
  2. Attempt to start the vehicle.

Does the DTC reset?

Go to Step 2

System OK