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Goodwrench9124, ASE Certified Technician
Category: Pontiac
Satisfied Customers: 3432
Experience:  Ase Master Certified, GM Master Certified Tech. Awarded GM Top performer,Hrybrid certified
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The CD player on my 2004 pontiac grand prix stopped working,

Resolved Question:

The CD player on my 2004 pontiac grand prix stopped working, so I bought a used one on ebay. I got it installed, and as expected, the theft lock light came on. I tried calling the local pontiac dealer and they told me I should see the word "LOC" or "LOCKED" in the display of the stereo. I am not seeing that. First step, I tore apart the old stereo and replaced the display in the "new" one. I got the same result. Stereo powers up, CD makes noise when eject button pushed, but only thing that lights up is the theft lock light, nothing on the display. Curious now if the display is really supposed to say anything at this point. Is it simply in lock mode at this point, with nothing on the display?
Submitted: 6 years ago.
Category: Pontiac
Expert:  Goodwrench9124 replied 6 years ago.
Hello and welcome, do you still have the used radio in the vehicle?
Customer: replied 6 years ago.
Yes, it is back in the vehicle.
Expert:  Goodwrench9124 replied 6 years ago.

The radio's in these vehicles have to be programmed with the vin number of the vehicle they are being installed in. if the used radio was not programmed and set up it wont function correctly in the vehicle


If there is anything you don't understand, please feel free to ask me to explain

Customer: replied 6 years ago.

I'm a little confused. Other research (along with talking to a pontiac service tech) has suggested that if I saw a "LOC" or "LOCKED" on the display, that the would talk me through getting it unlocked. My problem is that I get no display at all. Are you suggesting that they can't be moved from one vehicle at all? Or are you suggesting that it needs to be reprogrammed? If it needs to be reprogrammed, then my question revolves around getting that accomplished.

Expert:  Goodwrench9124 replied 6 years ago.

That is correct. the older radios would show loc, and a simple unlock procedure with a code would unlock the radio. the newer radios have to be set-up and programmed with a GM tech 2 scan tool. but after reviewing your question a little more. if the display is blank, this can only be a bad radio. which is real common on these vehicles. but after installing a know good radio, it has to be programmed with the vin number so it will operate correctly.


Perform the radio set up procedure

To setup a new radio for the vehicle, complete the setup procedure under the Special Functions menu of the scan tool.

If the new radio is not properly setup, the radio will display a locked message (LOC) or Calibrate.

Important: The radio set up will configure the following systems:

Steering Wheel Controls
Diagnostic Trouble Codes
Class 2 Radio Messages
Without learning the VIN, the radio will display a locked message (LOC).


The "Theftlock" theft deterrent system is a feature on all base and uplevel radios. There is no need to program a security code into the radio as in past model years. The theft deterrent system now utilizes class 2 serial data to determine if the radio is in the appropriate vehicle. Each time the radio receives the "run" power mode message, it compares the VIN information it has stored to the VIN information received from a module on the class 2 serial data circuit responsible for transmitting that information. If a mis-match occurs, the radio display will indicate to the user the radio is locked. Once this takes place, a DTC will set, the radio will not respond to any button presses and become inoperative. The two scenarios able to cause this condition are:

A radio is installed from another vehicle.
A module which communicates on the class 2 serial data circuit which supplies VIN information to the radio is replaced and not properly setup with the correct VIN information for that vehicle.

The only way to unlock the radio is by using a scan tool. Always refer to the table in this section to diagnose the "Theftlock" DTC for further information.

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