’03 Envoy to ’04 Sierra

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=34701
Printed Date: July 09, 2025 at 7:06 PM

Topic: ’03 Envoy to ’04 Sierra

Posted By: Jmallen01
Subject: ’03 Envoy to ’04 Sierra
Date Posted: June 27, 2004 at 11:43 PM

OK, removing the stock head unit from a 2003 GMC Envoy, and putting it in a 2004 GMC Sierra. Installs perfect, but when powered up, reads "LOCKED" across lcd. How do I fix it? Do I have to call the dealership to get an unlock code? Any help is appreciated.

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If it aint broke, I'll fix it til it is!

Replies:

Posted By: raydawg357
Date Posted: June 28, 2004 at 8:43 AM

Either call the dealer or check the owners manual for the other vehicle for the code.

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Do it right the first time

Posted By: kgerry
Date Posted: June 28, 2004 at 9:37 AM

i'd be surprised if it works even when you get it unlocked... the DC100 series of radios in the 03 and newer fullsize trucks are completely different from the other radios.... but to answer your question you need to burn the VIN of the vehicle into the radio to unlock it...we do this with a Tech II scan tool..you will have to go to an AC Delco radio centre like ourselves or else a GM dealer to have it done....but like i said you gamble the cost of doing this because the radio make not work in that vehicle.....

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Kevin Gerry
Certified Electronics Technician
MECP First Class Installer

Owner/Installer
Classic Car Audio
since 1979