Dead battery/PATS issue?

[kythri]

Drove my Expedition about 3 days ago, then parked it.

Went back out today, and it's DEAD dead.

Hooked up the charger for a couple hours, didn't do much more but give it enough juice to turn over once and click.

Figure that I may have a bad battery, so I'll diagnose that after a bit (swap out a known good battery) and see, but...

I jump started it to go over and pick up some stuff, left it running until I got back home.

Back home, I shut it off and tried to turn it back on. It's certainly got a fair amount of juice in it now, cranks over just fine, but, it won't start.

The theft light is blinking rapidly.

Went and found my spare keys (I actually have 5 total programmed keys from when I bought it with some janky aftermarket keys). One of the "good" Ford keys started it briefly, the others will not.

Now, none of them will start it, the theft light still blinks rapidly.

It still cranks over, just acting like it isn't getting fuel (which I believe is what PATS cuts out for a non-programmed key).

Anyone have this issue before? Could a dead battery have reset the programmed keys?

 

[Bedrck47]

the dead battery shouldn't have any effect on the pats system

How old is the battery/

Also disconnect the battery for about 20-30 minutes and then using a good battery reconnect and try again

Have you had any issues with a leaky windshield?

 

[kythri]

Battery could be older - it was in the truck when I bought it in August of 2013.

That's my first step in troubleshooting, I'll just buy a new battery, and if this one ends up being good, I've got a use for it elsewhere.

No leaky windshield problems.

I just went back out to the truck about 30 minutes ago, and it started right up.

Guh.

 

[Bedrck47]

there should be a date code on the side of the battery although that may not have anything to do with the battery being good or bad.
Would be best to have it load tested or if you have access to a know good battery tri it and see what happens before you go and buy a new one.

A bad battery can cause the problems you are having

 

[kythri]

Late reply, but, yeah, battery was the issue.

Battery technically was still under warranty, but I didn't buy it, so Les Schwab doesn't warranty it (original purchaser only).

Replaced it, solved the problem.

 

[Bdons_expy]

Awesome you got it fixed. I thought I'd throw I this out there for anyone else having issues. Maybe the thread will get picked up in a Google search or something.

If the battery in your key fob is going dead it can kill the truck battery if it's within range. In my old 03 f150 my truck was dead almost every morning, I couldn't figure out why, battery was good, alternator was good, I was about ready to tear my stereo system apart looking for a short or something. Someone told me to swap the battery in the fob, did it and sure as shat I didn't have a single problem for the remainder of the time I had the truck. I guess it sends a constant signal when the battery is low and it clicks the relay or whatever all night long until it's dead.


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[AbbadonTD]

The reason why it kills your battery is simple wireless tech. Its like a cell phone battery:

your 'Bars' of strength are an inverse indicator of the power your emitter/receiver is using to connect. When you have full 'Bars', that means the battery is using the lowest level power to connect (aka, you are near towers with "good signal").

The Key Fob and the receiver in the truck are also using a wireless. The fob is weak, so the vehicle has a receiver that can turn up the signal more and more if the fob is giving it a weak signal. More receiver power = more battery drain.

Thats how a key fob's dead battery drains the cars battery.

Its also why your cell phone dies when it has no signal so quickly. With no signal, its constantly searching at its highest power.

 

[Bdons_expy]

The reason why it kills your battery is simple wireless tech. Its like a cell phone battery:

your 'Bars' of strength are an inverse indicator of the power your emitter/receiver is using to connect. When you have full 'Bars', that means the battery is using the lowest level power to connect (aka, you are near towers with "good signal").

The Key Fob and the receiver in the truck are also using a wireless. The fob is weak, so the vehicle has a receiver that can turn up the signal more and more if the fob is giving it a weak signal. More receiver power = more battery drain.

Thats how a key fob's dead battery drains the cars battery.

Its also why your cell phone dies when it has no signal so quickly. With no signal, its constantly searching at its highest power.

Smarter man than I ha ha.


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