So I re filled with DEF fluid the other day and the warning light is still on and miles declining every time I turn on the vehicle to drive. Running out of miles before it says empty even though its not. Dunno if i'm able to make it to the dealer right away to get it fixed.

Any help

 

Did you fill it full (not overfull though)?
If it was counting down and you only added 2.5 gal, for example, that is not enough to trip the full sensor.
Fill it up, drive it and if operating correctly, it will reset to full.

If it does have 5 gal and you've been driving it, that sounds like a dealer trip unfortunately.

 

didn't know it took a whole 5 gallons... I have another gallon I'm going to fill it with now and see what happens

 

Don't overfill it. In fact, don't add any more right now.

Never add any DEF until it goes at least below halfway. The monitoring system doesn't reach the first trigger until under half full. If you fill it before it reaches that first sensor, then the system keeps counting down the miles without resetting.

 

The OP indicated he is still counting down so he is reading below half. He just needs to fill it to get it above that. His gallon may do the trick.

Best to buy more DEF and actually fill it and the sensor will trip.

 

Re-read my post. He may have filled it before it ever got below half full. In which case, it will continue to count down.

 

If it never got below 1/2 full it wouldn't be counting down. Right ?

 

That was my understanding/belief also.

Rob

 

Mine displayed a message, "800 miles to empty". I put in 2 1/2 gallons and the message went away the second time I restarted it.

 

It can. Happens more often than most people realize. Get calls on this almost daily from fleets and dealers. Instruct them to quit topping off the DEF all the time and their problems disappear.

 

Ok so (1) we need to know if he was already below 800 MTE.

While I don't recommend it due to areas with cold temps, I know for a fact at 200 MTE the thing fits 5 gal and it's not in the filler neck high enough to where I can see it.
2.5 gal when it's really low isn't enough for my truck to care that I added fluid.
Add more and I don't even have to drive it, the MTE message is gone and it reports full.

 

Everything is all good I added the other gallon I had laying around the house. I was about 300 miles to empty. I use be over the sensor mark now and will grab a few more gallons for next time to fill it all the way. Thanks for the help and advice fellas.

 

My kingdom for a real life DEF gauge like the RAM has. Sheesh.

Mine has gone straight to the 500 MTE countdown (aside: I notice the older trucks give longer countdowns? Is this true?) without ever presenting the below 1/2 full message.

Not the end of the world, but definitely needlessly frustrating...

 

My 2012 F250 XL gives the warning at 500 miles but doesn't go into countdown mode until 100 miles, then it chimes and warns every 5 miles after that, that it will reduce max speed to 50 mph and eventually shutdown.

What this thread should tell everyone is that you should just completely fill the tank when the warning comes on, not just put a couple of gallons in.

Another reason I only buy DEF at the pump at the truck stop, I can fill it completely every time, and 5 gallons (actually 4.8 is the most I have every put in to fill it), costs less than one 2.5 gallon jug from wally world or the parts store.

 

The only way to know it's below half full is to run the system check.
Otherwise, mine will not notify until 800 MTE (which it did on Wednesday).
I have the basic XLT information center.

I'll run mine down to 200 MTE or so unless I have to go on a trip.
Local station finally has a DEF pump so I don't have to get jugs.
Nearest DEF pump was over an hour away previously.