GM Service Manual Online
For 1990-2009 cars only

Circuit Description

A transponder is embedded in the head of the PASSKey III key. When the ignition switch is turned to the RUN, Bulb Test, or START position, the transponder is energized by the exciter coils surrounding the ignition lock cylinder. The energized transponder transmits a signal that contains its unique identification code. The theft deterrent module receives this identification code signal to determine whether the PASSKey III coded key is legitimate or invalid.

Conditions for Running the DTC

    • The ignition switch must be in the RUN, Bulb Test or START position.
    • The theft deterrent module runs a test of the transponder/reader every 0.3 seconds.

Conditions for Setting the DTC

The theft deterrent module detects that the key identification data from the transponder/reader is illegitimate. This indicates a failure of the transponder/reader.

Action Taken When the DTC Sets

    • DTC B2955 set as current DTC in the theft deterrent module.
    • The theft deterrent module does not send a fuel enable signal to the Powertrain Control Module (PCM).
    • The theft deterrent module rapidly flashes the SECURITY indicator in the instrument panel cluster.

Conditions for Clearing the MIL/DTC

    • The theft deterrent module no longer reads illegitimate data from the transponder/reader during the next ignition cycle.
    • A history DTC will clear after 100 consecutive fault-free ignition cycles. An ignition cycle consists of an ignition switch transition from LOCK/OFF to RUN.
    • Using a scan tool.

Diagnostic Aids

    • Check for a damaged or missing transponder on the PASSKey III key.
    • Check for using the incorrect type of key (non-PASSKey  III).
    • A poor or intermittent connection may cause this DTC to set. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

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

  1. The key must be a PASSKeyOverdriveIII 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 theft deterrent module is malfunctioning is to try an alternative component in the system.

  3. It is unlikely that more than one key will be defective.

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

  5. If only one key was available for the vehicle and the replacement key does not work, the theft deterrent module must be malfunctioning.

Step

Action

Yes

No

1

Did you perform the diagnostic system check for the theft deterrent system?

Go to Step 2

Go to Diagnostic Trouble Code (DTC) List/Type

2

Inspect the key for the following:

    • Damage to the molded key head.
    • "PK3" embossed on the key shank.

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

Go to Step 6

Go to Step 3

3

Are more than one of the keys available?

Go to Step 4

Go to Step 6

4

Attempt to start the vehicle using all of the available keys.

Do any of the available keys start the vehicle?

Go to Step 5

Go to Step 8

5

Use the scan tool in order to read current DTCs.

Do any of the available keys cause this DTC to reset?

Go to Step 6

Go to Diagnostic Aids

6

  1. Replace the damaged/inoperative/suspect key.
  2. Copy the mechanical cut of the available key on a PASSKey III replacement key.
  3. Perform PASSKey III programming procedure. Refer to Programming Theft Deterrent System Components .

Did you complete the repairs?

Go to Step 7

--

7

Use the scan tool in order to read current DTCs.

Does the replacement key cause this DTC to reset?

Go to Step 8

Go to Step 9

8

Replace the theft deterrent module.

Perform the PASSKey III programming procedure. Refer to Programming Theft Deterrent System Components .

Is the replacement complete?

Go to Step 9

--

9

Important: If the PASSKey III programming procedure was performed, all keys not learned at that time have been erased and will not be recognized. Perform the quick learn procedure on all keys 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