New Key?

fuzzyfurlong · July 30, 2009

I purchased my 2008 Sierra used and only got one key and key fob. I bought another key and fob but when I got the key cut it won't work. I re programed the fob and that works fine but the key will not start the truck. Does the original key have a chip? it doesn't look like it does but if I hold the original key next to the steering column the truck will start for a second then shut down?

Walk9508 · July 30, 2009

Use the original key and start the engine, then stop the engine and remove the key. Insert the new key and start the truck.

MS3DALE · July 30, 2009

Use the original key and start the engine, then stop the engine and remove the key. Insert the new key and start the truck.

+1 ^^^ What he said! ^^^

fuzzyfurlong · July 31, 2009

thanks . now it will start the truck . but the little security light (car with the pad lock through it ) comes on and the display says service theft control system.

fuzzyfurlong · August 1, 2009

any idea how i get the security light to go off with the new key?

jrrod2004 · August 1, 2009

I purchased my 2008 Sierra used and only got one key and key fob. I bought another key and fob but when I got the key cut it won't work. I re programed the fob and that works fine but the key will not start the truck. Does the original key have a chip? it doesn't look like it does but if I hold the original key next to the steering column the truck will start for a second then shut down?

no, but those new keys are "precision" cut as described to me by my local Cothron's. Have no idea if there is any truth to this but every key that I have gotten done has worked but not from Walmart, Home Depot, Lowes or any other store....

brims · August 1, 2009

I purchased my 2008 Sierra used and only got one key and key fob. I bought another key and fob but when I got the key cut it won't work. I re programed the fob and that works fine but the key will not start the truck. Does the original key have a chip? it doesn't look like it does but if I hold the original key next to the steering column the truck will start for a second then shut down?

no, but those new keys are "precision" cut as described to me by my local Cothron's. Have no idea if there is any truth to this but every key that I have gotten done has worked but not from Walmart, Home Depot, Lowes or any other store....

Maybe their key cutting machines are worn out? Or the cutting blade at least.

Dmas · August 1, 2009

where did you get the key from? does it have a "+" sign on the plastic part?

Spurshot · August 1, 2009

My understanding is that my 08 truck has a chipped key (it does indeed have a + sign on it) and is programmed by going thru the sequence described above (start with orig, remove, start with ne key). I bought two new GM blanks and have yet to have them cut.

MS3DALE · August 1, 2009

My understanding is that my 08 truck has a chipped key (it does indeed have a + sign on it) and is programmed by going thru the sequence described above (start with orig, remove, start with ne key). I bought two new GM blanks and have yet to have them cut.

Yep,Actually all '07-up GMT900 trucks have the resistor key.

brims · August 1, 2009

My understanding is that my 08 truck has a chipped key (it does indeed have a + sign on it) and is programmed by going thru the sequence described above (start with orig, remove, start with ne key). I bought two new GM blanks and have yet to have them cut.

Yep,Actually all '07-up GMT900 trucks have the resistor key.

Thought the resistor was in passlock 2 or something and the 900s have passlock 3+.

sonjaab · August 2, 2009

Its called a "transponder" key.

Note the cross in the circle on the key shank below the plastic head.

jake1530 · August 2, 2009

This is a very informative thread. I need to check the key I bought a while back and stored it in the bed as a backup to see if it will even start the truck, my truck is an 05. Can I ask, when you wrote "but if I hold the original key next to the steering column the truck will start for a second then shut down?" Do you mean in the literal sense just holding it next to the column it will start? Thanks in advance, Jake.

MS3DALE · August 2, 2009

This is a very informative thread. I need to check the key I bought a while back and stored it in the bed as a backup to see if it will even start the truck, my truck is an 05. Can I ask, when you wrote "but if I hold the original key next to the steering column the truck will start for a second then shut down?" Do you mean in the literal sense just holding it next to the column it will start? Thanks in advance, Jake.

Your truck doesn't have a resistor or transponder key,Its only the '07-up GMT900 trucks.

Spurshot · August 2, 2009

This is a very informative thread. I need to check the key I bought a while back and stored it in the bed as a backup to see if it will even start the truck, my truck is an 05. Can I ask, when you wrote "but if I hold the original key next to the steering column the truck will start for a second then shut down?" Do you mean in the literal sense just holding it next to the column it will start? Thanks in advance, Jake.

Your truck doesn't have a resistor or transponder key,Its only the '07-up GMT900 trucks.

My 99 GMT800 doesn't have a transponder key. I've bought spare keys while on long hunt trips in the middle of nowhere South Dakota (Huron) and they were plain keys. I've cut the plastic completely off a key for a wallet spare and it works.