GM Radio won't unlock

[greasybob]

I'm kind of a sucker for the hard jobs. Should be able to do anything a dealer can do with the right tools. Most flashes go with out issues, used stuff is always a gamble. I just want to know if GM changed anything that would not allow the VIN to be re written or if any one else has seen this happen.

[Speedybon]

You will probably lose money on programming. We would build the car to show all options and download it with too an SD card. Some would take hours. Not a money maker. I would stay away from Radio programming.

[Glide]

As I said,I haven't tried a used Nav radio in a GM,but I found this info in service information "

It is critical to use the service replacement Communication Interface Module only in the vehicle for which it was ordered "

Another part of SI refers to the Nav radio as the communication interface.So maybe a new Nav radio has the VIN written to it before it is shipped to the dealer.

[SnapOnKid]

I have not done a used Nav that new. The one I did do,

I Tried reprogramming the software and It went through the entire process and said it failed near the end. I was thinking either the radio was messed up or maybe there was something else that needed to be done and there was a super secret trick that was not being esplained...

On the normal radios, I have to reprogram the software in order for the new vin to be learned and for it to unlock. Sometimes a standard vin reprogram will take and sometimes it will not but even when it does take usually the Radio remains locked. When I reprogram the software it seems to overwrite the vin and unlock it every time.

The 2nd time I tried to just re-write the vin. I verified by scanning the radio again and looking for the vin. When I cycled the Key, the nav unit came to life and was fully functional. I was in disbelieve... When I scanned the car again it had the correct matching vin.

I used a Genuine Tech 2 and used it as a passthrough when attempting to program.
But The Vin Unlock portion for the nav radio was in the scan tool and not the SPS subscription.

[Nate75]

after 2010 almost all GM vehicles wil not allow the vin to be changed in any module. I have tried several and ended up opening the radio up and swapping the smaller board that doesn't have the vin in it and it resolved the issues. there are systems out there to connect directly to the PROM chip and reprogram the vin, but I have not tried them.

Nathaniel