2004 Chevy Suburban Emissons Fail - Not Ready

Your going to have to give me something to work with.

Yes. Did you originally fail for emissions and have the codes cleared? Did you have no check engine light on and went to get sticker and they failed for not ready? Does your battery stay charged over night or do you have to jump start it? Check your coolant temp gauge on dash and tell me if it reads normal or if it always stays on the cold side.

There are only a couple things that can cause you not ready. First of all is your vehicles ambient temp sensor and or cooling system temp sensor are not accurate. To run a readiness test your vehicles computer must see engine temp and outside air temp to be equal, this tells computer the car is cold. If these sensors never read the correct temps then the car will never run a raeadiness test. Also your computerhas keep alive memory and if this fails it will reset your computer every time you shut your car off. You need to have these things checked. Hope this helps