GM Service Manual Online
For 1990-2009 cars only

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 module sends the enable password via the serial data circuit to the powertrain control module (PCM).

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3055 No Transponder Modulation or No Transponder

Conditions for Running the DTC

The microprocessor runs the program to detect a check sum error after each power up. This program runs only if the DTC B1982 or B1983 are not set as a current DTCs.

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 theft deterrent control 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 VTD system is NOT active and the vehicle will start. The theft deterrent control module WILL send its enable password 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 a class 2 message containing a disable password to the PCM.
    • The vehicle will not start.
    • The theft deterrent control module sends a class 2 message to the instrument cluster to illuminate the SECURITY indicator on steady.

Conditions for Clearing the MIL/DTC

    • The theft deterrent control module clears the current status of the DTC when it senses a valid, memorized, transponder value from the ignition key.
    • The DTC can be cleared by using a scan tool.

Test Description

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

  1. Verifies the condition for setting DTC B3055 is current.

  2. The key must be a passkey III (PK3) transponder key with an operating transponder for the system to work.

  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. 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. 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. 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. 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 the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Does the scan tool indicate DTC B3055 is current?

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 passkey III (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. Use the scan tool in order to clear the DTCs.
  2. Attempt to start the vehicle using all of the vehicle's available keys.
  3. Using a scan tool, observe for any DTCs during each starting attempt.

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 B3055 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 PK3 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 B3055 to set?

Go to Step 9

Go to Step 10

9

Important: If a 10 minute or 30 minute re-learn procedure was performed, all keys not learned at that time have been erased and will not be recognized. Perform the adding keys procedure or instruct the customer on how to perform the adding keys procedure. Refer to Adding Keys .

Replace the theft deterrent control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.

Did you complete the replacement?

Go to Step 10

--

10

Important: If a 10 minute or 30 minute re-learn procedure was performed, all keys not learned at that time have been erased and will not be recognized. Perform the adding keys procedure or instruct the customer on how to perform the adding keys procedure. Refer to Adding Keys .

  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