GM Service Manual Online
For 1990-2009 cars only

Circuit Description

When an ignition key is inserted into the ignition lock cylinder, the transponder that is embedded in the head of the key is energized by the exciter coils that surround the ignition lock cylinder. The energized transponder transmits a signal that contains its unique value, which is received by the VTD module . The VTD module then compares this value to a value stored in memory (learned key code). If the value is correct, the VTD module sends the enable password via the class 2 serial data circuit to the PCM.

Conditions for Running the DTC

The ignition switch must be in the RUN position. The VTD module cannot have a current DTC B1327.

Conditions for Setting the DTC

The VTD module is unable to measure the ignition key transponder value for 1 second. This may be due to a damaged or missing transponder pellet, a non Pass Key® III key, or a damaged exciter. If the conditions occur after the engine is running, setting the DTC may take up to 30 seconds. Refer to the Important statement below.

Action Taken When the DTC Sets

    Important: If the VTD 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 VTD 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 VTD module is "fail enabled", the Pass Key® III system is NOT active and the vehicle will start. The module WILL send its enable password even if a transponder value is not received. The VTD module will remain "fail enabled" until the module measures a valid key transponder value.

  1. The VTD module sends a class 2 message containing a disable password to the PCM.
  2. The vehicle will not start.
  3. The VTD module sends a class 2 message to the instrument cluster to illuminate the SECURITY indicator on steady.

Conditions for Clearing the MIL/DTC

The VTD module clears the current status of the DTC when the module senses a key code from the exciter. If the code is not from a learned key, a DTC B2960 will be set.

Test Description

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

  1. The key must be a Pass Key® III transponder key with an operating transponder for the system to work.

  2. The only method to confirm whether the transponder in the key or the VTD (Pass Key® III) module is malfunctioning is to try a alternative component in the system. The vehicle was delivered with 4 keys.

  3. The possibility is unlikely that more than one key will be defective. If all keys do not work, the VTD (Pass Key® III) module must be malfunctioning.

  4. If the vehicle has a malfunctioning VTD (Pass Key® III) module that malfunctioned during an ignition cycle, the system will be "fail enabled" and the vehicle will start for all keys. In this case, the code B3055 will remain set and be current for all keys.

  5. If a new key must be tried, the key must have the proper mechanical cut and the VTD (Pass Key® III) module must "learn" the transponder value.

  6. If only one key was available for the vehicle and the replacement key does not work, the VTD (Pass Key® III) module must be malfunctioning.

Step

Action

Yes

No

1

Did you perform A Diagnostic System Check - Theft Deterrent System?

Go to Step 2

Go to Diagnostic System Check - Theft Deterrent

2

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 3

3

Are more than one of the vehicle's keys available?

Go to Step 4

Go to Step 7

4

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

Do any of the available keys start the vehicle?

Go to Step 5

Go to Step 9

5

Do all of the available keys cause DTC B3055 to set?

Go to Step 9

Go to Step 6

6

Do any of the available keys cause DTC B3055 to set?

Go to Step 7

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

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 VTD module learn procedure. Refer to Programming Theft Deterrent System Components .

Is the replacement complete?

Go to Step 8

--

8

Does the replacement key cause DTC B3055 to set?

Go to Step 9

Go to Step 10

9

  1. Replace the VTD module. Refer to Theft Deterrent Module Replacement .
  2. Perform the VTD module learn procedure. Refer to Programming Theft Deterrent System Components .

Is the replacement complete?

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 Quick Learn Procedure or instruct the customer on how to perform the Quick Learn Procedure. Refer to Programming Theft Deterrent System Components .

  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