I have an 05 Monte LT and have tried programming a cheap Chinese FOB as well as a GM FOB and neither will work. I followed the guides in my manual and the ones online with no success. Any ideas as to what would cause it not to work?

 

I think I read about this once before on here, and they determined that the fob was not compatible with that car.
So they got a correct one and it all worked.
If I recall that all of the programing for one of these is run thru the radio.
I did one on an Impala once and it programed thru the radio too. I think it was an 03 Impala that I did for a friend of mine. It took me a few times before I got it as I remember.

 

I have seen on other posts people talking about getting the correct fob. I have no idea how to find out what the exact fob would be for my car. Mine says GM/LEAR on the back of it. I have tried over 100 times to do it through the radio and it ends up timing out.

 

I bought a pair of fobs on ebay for a 2006 Trailblazer I had. The seller had a chart to show what models were compatible with what fobs, and I just chose the one for my vehicle. Went through the setup instructions in the owner's manual and everything worked perfectly. I may have to do that soon with my '07 MCSS as the buttons on one of them are pretty well worn...

 

Im starting to wonder if it has something to do with the cars security. When my key is in the on position my dash display flashes between battery and security. So im not sure if its the passlock system or if its the fob receiver under the upper dash trim panel. Guess its time to start replacing things and see what works.

 

Couple of ideas too My local ace hardware has them also not sure if they help with programing on not.
2. Maybe the Battery is not good in them?
found these on ebay as an OEM

https://www.ebay.com/sch/i.html?_fro...M&_dcat=184651