Adding the Customers Code

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Adding the Customers Code
WARNING: This page is about a different car, the 2003 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.

Perform the following steps in order to add the customers code:

  1. Turn the ignition to the ACC or RUN position.
  2. Turn the radio OFF.

    Important:  If SEC is displayed the theft deterrent feature is already activated. Remove the old code before entering the new code.

  3. Press and hold the pushbuttons 1 and 4 for approximately 6 seconds until the display changes to" " ".
  4. Press the HR button.
  5. Set the first 2 digits (0-19) of the code with the HR button.
  6. Set the next 2 digits (0-99) with the MIN button.
  7. Press the AM-FM button in order to enter the code.
  8. Repeat steps 3-5 when REP then 00 are displayed. This will confirm the following:
    • The customers code
    • Activates the theft deterrent feature
    • After step 5, will display SEC in order to show the theft deterrent feature has been activated.

    Important:  If " " " is displayed after pressing the AM-FM button, the customers code has not been entered.

  9. Anytime the ignition is removed and the THEFTLOCK® is activated, the THEFTLOCK® light will flash once every 2 seconds. Anytime the battery power is cycled and the ignition is ON, the display will show LOC. The radio will then need to be unlocked by either the customers code or the factory backup code.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.