Have you recently done anything under the hood of the truck? Sometime ago, I was under my hood checking things out. Checking oil, hoses, just looking to make sure all was well. The next day it was kinda of hot so I tried to start it to let the cab cool down before I went out. Low and behold, it honked and the lights flashed, but didn't start. What the H@@l! It worked the other day. Had no idea what it was. It was like this for several days before I decided I was gonna call to take it in. But I decided to see if maybe I might of hit something while I was under the hood. You never know? Because it was working before that. After a few minutes of just standing there looking dumb, I noticed something. On the drivers fender lip, between the airbox and overflow tank, is the plunger switch and bracket for the hood. It was bent down and when the hood closed, it didn't press on the switch. I guess I must of leaned on it and bent it down. So I bent it back up right, shut the hood and hit the remote, and it started right up .

 

Im having a similar problem with my 08, its a factory installed system but not sure which model. everything was fine until this summer it stopped working for no reason. its supposed to beep once after the button is pressed, then lock the doors and then beep once again as it starts. but when i press the button now it beeps once as normal, then locks the doors but then instead of starting it beep six times in rapid succession.

the truck is gold with beige interior so it didn't get too hot in the summer and i didn't pay much credence to it but now that winter is here it seems to have jumped to a pretty high priority on my list.

any help would be greatly appreciated.

 

My 2012 does that every once in a while. It simply refuses to start but honks no matter how many times I try. I manually start and go on. The next time I remote start, and I almost always remote start, it works fine and continues to do so for several more months. It gets stubborn like that about three times a year.

 

I had the same problem in my 09 F150 XLT> hit the remote start and all seems normal, even powers up, then honks 6 times and powers down. What i found out was 6 honks means the system is in Service/Valet mode. Now mind you 6 honks COULD MEAN there is a physical service problem that needs repair, but more times than not it is just the Service/Valet mode accidentally being turned on (I've read by unknowingly pressing buttons while your keys are in your pocket) and just needing to be turned off. These steps worked for my truck's 6 honk issue and turned off the Service/Valet mode, hopefully they work for you as well:
1- enter your car (drivers side) then make sure all doors and hatches are closed
2- put the key in the ignition and turn it to the ON position (all the way just before the engine starts)
3- press and hold the brake pedal
4- while still pressing down on the brake pedal, press the button on your FOB (key chain) to your remote start 3 times (mine has a pic of a key and has its own remote)
5- the horn SHOULD honk 6 times indicating the mode was turned off/on, but if it does not honk at all or even if it only honks once the process may have still worked (mine honked once and worked)
6- remove the key from the ignition and release the brake pedal
7- with all the doors still closed and the key removed now try to use the remote start and see if it works
8- if this does not work i would try the process one more time, and if it still does not work there may be a physical issue that needs repaired.