GM Service Manual Online
For 1990-2009 cars only

Code Registration Description

The key has 2 codes that have to be registered. The key code (immobilizer code) and the wireless code. Both of these codes need to be registered. The following paragraphs refer to the registration procedures.

Automatic Key Code Registration (New Registration)

Important: If all ignition keys are lost, replacement of the transponder key ECU assembly is required.

The new registration of the key codes (immobilizer codes) is made automatically. When registering a new transponder key ECU, the key codes must be registered. A new transponder key ECU starts in the automatic key code registration mode. In this mode, a maximum of 4 key codes for 3 master keys and 1 sub key can be registered. Since the transponder key ECU can distinguishes types of keys, any registration order is acceptable. Proceed as follows:

Important: The security indicator is blinking until the first key is inserted into key cylinder.

  1. Insert the key into the ignition key cylinder. The security indicator will turn ON for approximately 1 second and then turn OFF.
  2. Remove the key. The security indicator will turn ON.
  3. Repeat the first two steps, to register another key. When no key is inserted into the key cylinder while the system is in automatic key code registration mode, the security indicator remains ON.

When the maximum number of the key codes is registered, the security indicator remains OFF until the last key registered is removed. After the key is removed, the security indicator starts blinking. When the immobilizer system is operating normally and the key is pulled out, the security indicator blinks continuously.

If the key code registration has failed in the automatic key code registration mode, code 2 - 1 will be output from the security indicator. Trying to register an already registered key will cause code 2 - 2 to be output when the key is inserted. If the number of registered key codes exceeds the limit, code 2 - 3 will be output from the security indicator.

The automatic key code registration mode can be forced to end, when at least 1 key code (immobilizer code) for the master key has been registered. If not using the scan tool, turn the ignition switch ON and OFF 5 times within 10 seconds using the already registered master key. If using the scan tool, follow the instructions on the scan tool display to end new key code registration mode.

Additional Key Registration

Registering and additional key is done by using the scan tool. A maximum of 5 key codes and 3 sub key codes can be registered. Registration mode will end if any step is not completed within the specified time.

Important: When only the ignition key cylinder has been replaced, you can lock or unlock doors by wireless operation using the new key with built in transmitter but not by inserting it in the door key cylinder. Therefore, keep the original key for door lock or unlock operation in order to avoid malfunctions caused by a dead transmitter battery in the new key.

When the ignition cylinder or the key cylinder set is replaced, remove the transmitter module from the original master key. Then install this transmitter module to a new key and use it as a master key. If necessary, use this master key to register other keys. Proceed with additional key registration as follows:

Important: The security indicator is blinking until the first key is inserted into key cylinder.

  1. Insert the already registered master key in the ignition cylinder and turn the ignition switch ON. The security indicator will turn OFF.
  2. Install the scan tool and select the following data path:
  3. • Select IMMOBILIZER,
    • Select ID UTILITY,
    • Select IMMOB CODE REG
    • After completing the above operation, proceed to the next step in accordance with the prompts on the scan tool. This must be accomplished within 120 seconds. The security indicator will turn ON.
  4. Remove the master key. This must be accomplished within 20 seconds of the instruction on the scan tool. The security indicator will remain ON.
  5. Insert the key to be registered in the ignition key cylinder. This must be accomplished within 10 seconds. The security indicator will begin blinking.
  6. Wait 60 seconds for the key to be registered. The security indicator will stop blinking and turn OFF when the key is registered.

If the key code registration has failed in the automatic key code registration mode, code 2 - 1 will be output from the security indicator. Trying to register an already registered key will cause code 2 - 2 to be output when the key is inserted. If the number of registered key codes exceeds the limit, code 2 - 3 will be output from the security indicator.

Key Code Erasure

Erasure of key codes can be accomplished using the scan tool. All codes will be erased except for the master key which is used for erasing the key codes. In order to use a key for which the code has been erased, it is necessary to register the key code again. Registration mode will be cancelled if any step is not completed within the specified time. Proceed with key code erasure as follows:

Important: The security indicator is blinking until the first key is inserted into key cylinder.

  1. Insert the already registered master key in the ignition cylinder and turn the ignition switch ON.
  2. Install the scan tool and select the following data path:
  3. • Select IMMOBILIZER,
    • Select ID UTILITY,
    • Select IMMOB CODE ERA
    • After completing the above operation, proceed to the next step in accordance with the prompts on the scan tool. This must be accomplished within 120 seconds. The security indicator will turn ON for approximately 1 second and the turn OFF.
  4. Remove the master key. This must be accomplished within 10 seconds of the instruction on the scan tool. The security indicator will turn ON.

ECU Communication ID Registration

The ECU communication ID should be registered when the transponder key ECU is replaced in order to match it to PCM communication ID. The engine cannot be started unless the PCM communication ID matches.

Do not turn the ignition switch from ON to OFF 20 times or more before setting the ECU communication ID. If this operation is likely to be performed 20 times or more, disconnect the cable from the negative battery terminal in order to avoid disabling engine start. Failure to do sow will result in the engine not starting unless the transponder key ECU is replaced with a new one.

After the registration, turning the ignition switch may not start the engine on the first try. If so, turn the ignition switch again. After the engine is started, erase DTC B2799 by either using the scan tool or by disconnecting the battery for 30 seconds.

Register the ECU communication ID after the transponder key ECU is replaced as follows:

  1. Connect STT tool (P/N 09843-18040) to DLC connector terminal 4 and terminal 13.
  2. Turn the ignition switch ON and leave it as is for 30 minutes.
  3. Check that the engine starts.