So my car is now 3 years old, and if it sets for more than three days my fob wont open door so i have to use the key from back then get in by pull string and try to wake up it,, reset the alarm ,, it say no Fob detected but i keep pressing the unlock lock eg.eg. and then it will start
Can this just Be the Battery in the Fob ??? thanks for the reply

 

probably, I replaced my batteries in my 2014 early this year.
they're cheap,

 

I'd bet it's the battery as well.

 

Not sure what else it COULD be.... try the battery route....LK

 

Fob battery, my 2014 ATS fob did the same thing yesterday. I don't know whether it is the fobs are now more power hungry or if the batteries are of poor quality but my 2008 CTS still had one original fob battery and the other was within 2 months of original and both were fine after trading it in after six years of ownership; it has the same RKE system as the C7 with push button start and keyless entry.

I am confident both original CTS batteries would have made it six years but I accidentally sent one fob through the wash after my first oil change so that battery only had 5 years and 10 months on it

My 2006 GMC Sierra still has both original fob batteries but its fobs are only used for lock/unlock.

Be very careful when buying replacement batteries from some of the major Internet sites (like that big one starting with an A) because there are a lot of old and counterfeit batteries floating around. For convenience I bought some that way last years for other electronic devices and the packaging looked like a decent imitation but I don't believe they were real Panasonic batteries and all were near dead and useless when they arrived, the date code on the external package didn't mesh with the current Panasonic case style either. Feedback on the site showed similar problems with Sony, Duracell, and Everready/Energizer cells also so it is probably better to just buy from a regular retail store.

 

I replace my FOB batteries yearly just to prevent problems, the batteries are cheap & easy to change.

 

If the batteries in the fob are three years old, they need to be replaced.

 

they are 3 years old thanks

 

The battery on my 2015 started acting weird after only 22 months, so I'll bet on the batteries, too. A new battery should show about 3.3V and mine showed 3.05V, so it doesn't take much for it to become a problem.

 

Every 3 years I change both the FOB's & car's batteries. Don't need any grief.

 

I found that the very BEST test for the key fob battery is to lower a convertible top remotely.... it has to maintain signal all through the cycle.

A weak battery will cause it to stop before the full opening cycle... give it a try...LK