GM ECU Installation Instructions

Before beginning:

Please ensure that you did match your part number and service number as these units are part number / service number specific, not vehicle specific. If your part number and service number is not in the listing description, please contact us with your part number and service number and we can determine if this is the correct replacement. Do not begin the next steps until this is verified as this can cause a locksmith to be needed to move forward.

Please locate your key based on the above images and locate the correct instructions based on your specific key. Information for programming additional keys and the crankshaft relearn instructions are on the last page.

Passlock (Coded Lock Cylinder)

To perform a Passlock system relearn, make sure the vehicle battery is fully charged, as it will be used for 30 minutes without the alternator for charging. Connect a battery charger to the battery to ensure steady power while programming. Both the IPC/BCM and PCM must be working and communicating with each other to successfully complete the relearn.

Turn ignition on.
Attempt to start the engine, and then release the key to the ON position.
Observe the security indicator light. After 10 minutes, the security indicator light will turn off. DO NOT CONTINUE UNTIL THE LIGHT TURNS OFF.
Turn ignition to the OFF position, and wait 10 seconds.
Attempt to start the engine, and then release the key to the ON position.
Observe the security indicator light. After 10 minutes, the security indicator light will turn off. DO NOT CONTINUE UNTIL THE LIGHT TURNS OFF.
Turn ignition to the OFF position, and wait 10 seconds.
Attempt to start the engine, and then release the key to the ON position.
Observe the security indicator light. After 10 minutes, the security indicator light will turn off. DO NOT CONTINUE UNTIL THE LIGHT TURNS OFF.
Turn ignition to the OFF position, and wait 10 seconds.
Vehicle has now learned the new password. Start the engine. 12. With a scan tool, clear any trouble codes.

Passkey II (Resistive Chip Ignition Key)

To perform a relearn on a Passkey II system, make sure there is a fully charged battery in the vehicle. The battery will be used for 30 minutes without the alternator for charging. Connect a battery charger to the battery to ensure steady power while programming. Both the BCM and PCM must be working and communicating with each other to successfully complete the procedure.

Insert ignition key and turn to the ON position. Do not attempt to start the engine. Leave the key in the ON position for approximately 11 minutes. The security light will be on or flashing for the 11-minute period. Do not proceed to Step 2 until the security light turns off or stops flashing.
Turn the ignition switch to the OFF position for 30 seconds.
Turn the ignition switch to the ON position as in Step 1 for 11 minutes. The security light will be on or flashing for the 11-minute period. Do not proceed to Step 2 until the security light turns off or stops flashing.
Turn the ignition switch to the OFF position for 30 seconds.
Turn the ignition switch to the ON position as in Step 1 for 11 minutes for a third time. The security light will be on or flashing for the 11-minute period. Do not proceed to Step 2 until the security light turns off or stops flashing.
Turn the ignition switch to the OFF position for 30 seconds for a third time.
Turn the ignition switch to the ON position for 30 seconds.
Turn the ignition switch to the OFF position.
Attempt to start the engine. If the engine starts and runs, the relearn is complete. NOTE: If the theft deterrent relearn procedure does not work, please try the procedure again.

Passkey III (Transponder Ignition Key)

To perform a Passkey III system relearn, make sure there is a fully charged battery in the vehicle. The battery will be used for 30 minutes without the alternator for charging. Connect a battery charger to the battery to ensure steady power while programming.

Insert a master key (black head) into the ignition switch.

Turn key to ON position without starting the engine. Security light should turn on and stay on. NOTE: Certain vehicles are equipped with a Driver Information Center (DIC) display. The DIC will display a “Start disabled due to theft” message instead of a security light.

Wait for 10 minutes or until the security light or DIC message turns off.

Turn key to OFF position for 5 seconds.

Turn key to ON without starting the engine. Security light or DIC message should turn on and stay on.

Wait for 10 minutes, the security light or DIC message must turn off.

Turn key to OFF for 5 seconds.

Turn key to ON without starting the engine. Security light or DIC message should turn on and stay on.

Wait for 10 minutes, the security light or DIC message must turn off.

Turn key to OFF. The key transponder information will be learned on the next start cycle.

Start the vehicle. If the vehicle starts and runs, the relearn is complete. NOTE: If the theft deterrent relearn procedure does not work, please try the procedure again

A key relearn process is also required. Your vehicle will not start until this has been completed. Once the PCM has the VIN programmed and the key relearn process is completed the vehicle will start.

A crankshaft and throttle relearn are also recommended when replacing the ECU. A scan tool is required to complete the crank and throttle relearn. Your vehicle may not run properly if these are not completed. You will need access to a scan tool capable of doing this procedure to do this and clear any related trouble codes (Code P0315). Be sure your mechanic is capable of completing these before purchasing. The vehicle will run normal but the ”service engine soon” light will come on and a trouble code may be stored until this is resolved.