How exactly does this sentry key thing work in these new trucks?

I went to the locksmith as I only have one key, he can't duplicate it for programming, but can duplicate a plain key to unlock the door. So I did that to keep a spare, I tried this plain key, it started the truck but then it immediately shut down.

I searched the forums, locks like I need 2 fobs to program spares. bummer.

So it got me thinking, is there something in this black key fob that activates something else, and if the batteries go dead on the key, will it leave me stranded?

Thanks,
John

 

There is a sensor in the key to help prevent auto theft. The dealer can get you a second key. It wont be cheap though.

 

I've read here $200 on up.

So its a magnetic proximity sensor based, or does something in the ignition power the key?

What about the battery, does it need to be in good condition, will the truck start with a dead key fob?

 

It has some chip inside the key that the truck has to "see" when you start it. With a properly cut key without the chip, the truck will start but the ECM will shut it down. It should still start with a dead fob battery.

 

dont ya just love this crap. what ever happened to a plain old freakin key

 

I hear ya. All these new electronic nannies get annoying.

 

Ill second that. Sentry key is an annoyance. I keep a key in my wallet that opens the door but have to keep a spare key hidden in my truck to get it to start...

 

The key sensor is within a certain proximity of where the key is inserted - or at least as I understant it, that's how it works. You could probably take apart the surround on the steering column and affix your sentry key somewhere close bye and forever just use a regular cut key to manually lock and unlock your truck AND also run the ignition. Of course, it kind defeats the sentry key function, eh?

I would replace the battery every 4-5 years, that would maybe end the worry that a dead battery could cause OR keep a spare battery for it in the glove compartment. The key could then be used to open the door lock to get to the new battery.

Not too many choices regarding having these keys since they are all but built into the truck in such a manner that we can't have it both ways.



CD

 

A guy at work snapped his key in half on his Charger. He got a spare cut then carried the sensor part on a key ring with it.

 

I was curious, so I just went and tested this out.

Yes, the truck will still start and run without a battery in the key fob. If the battery is removed after the truck is started, it will stay running as well. The sensor for the Sentry system is in the circuit board inside the key fob. I set the circuit board from the key fob on top of the steering column and several other places and it wouldn't stay running. Basically the circuit board has to be within about an inch of the key in order to work from what I could figure.

Does answer the original question though. A dead battery in the key fob will not cause a problem.

 

I keep wondering how far back this system goes on our trucks.
I also wish someone would make an override for it....

 

I know they go back to 06, had it on my truck. I think that is when it became standard.

I believe it goes as far back as 03 (optional) though.

 

the battery in the fob ONLY activates the keyless entry. there is a chip in the key. the key is inserted into the ignition cylinder. there is a coil that is around the ignition cylinder (sentry module) and that coil reads the resistance of the key. the key fob is only for keyless entry unless you have the factory (or aftermarket addon alarm).

06 and newer pretty much all have sentry.

03-05
black key= no sentry
gray key= sentyry

 

oh they do, that is why the good thieves know how to get around it for about $60 online no questions asked.

 

It started in 98