I have a stock 2011 F250 Superduty FX4 ...it came with stock 17 inch alloy wheels and 265/70/17 tires. In Dec 2012 I purchased a set of 4 stock Ford 20 inch polished aluminum wheels and 275/65/20 Michelin A/T 2 tires. The issue that I am having is a check engine light P1635.....I took the truck to the dealership to get the truck reprogrammed because of the larger tires.....and after the 2nd visit is when the check engine light came on .....There is a conflict with the new wheel and tire size and the traction control system. To resolve this conflict I was told that the stock 17 inch wheel and tire will have to be put back on the truck and it reprgrammed back to the stock settings......At this time I'am driving my truck with a check engine light on all the time......

 

That sucks...a lot. Do you have the original wheels and tires or did you sell them?

 

I just sold the wheels this past Sunday.......Tires I still have....at this point I will not be selling them. What I really need is to have Ford come up with some type of FIX.....I'am at this time escalating this with Ford......looking for maybe some Ford software fix......

 

I think I'd get a second opinion from another dealer. Maybe the dealership isn't familiar with how to correctly program the tires size. This just doesn't seem that hard. Mine was reprogrammed without the original wheel/tire combo...so I KNOW it can be done.

 

The dealership has been working with Ford.......and Ford stated there will be a conflict.....check engine will remain on and will not go away with the stock upgraded tire and wheels. Tire / wheel sizes and traction control will be conflict .......stock program in truck / gear ratio / traction control = safety issue so you will get a check engine light ........to resolve put back stock 17 inch wheels and tires / reprogram and my problem solved.......

 

Seems fishy to me. Half the trucks in this forum have over sized tires on them without problems.

 

Not as far fetched as you may think.

If you have the 3.31, you cannot have 20 inch wheels.

Here is what I went through, twice.
I have 18's which had OEM 275/65 tires.
I upgraded to 295/70's on the same 18" OEM wheels.
My speedometer used to be two MPH slow, now it's three MPH fast so I went to my dealer to see what we can fix.

Every option other than programming for an 275 tire, 18 inch wheel (default) would throw a CEL; every time.
I don't know what the highest 18inch size they selected was but it too threw a CEL.
All 20 inch options of course were CEL.
I watched the second time. Those are the only times I've ever seen a CEL on my dash.

You can't purchase a truck with 20 inch wheels and a 3.31 axle ratio so Ford didn't limit that on paperwork, they programmed it in too.

If you have a 3.55 axle ratio, that's a different story.

 

I also went thru this. I have a 2011 F-250 that came with 18" wheels and the 3.31 axle. I put on 295/70/18 tires. I took it to the dealership and asked them to set the largest 18"wheel setting available. I specifically told him do not set a 20" setting because I knew it would throw a CEL. About an hour later I ran into the tech who said it took him 5 minutes to set the tire size and 45 minutes to get rid of the CEL because he set a 20" size to match my tires.

From the problem you are having I assume you must have a 3.31 axle. You do not need to put your old tires back on. I believe the only limitation you have is that you cannot use a 20" wheel size. You can use any wheel size that would have been available from the factory for your truck. That should be any 17" or 18" wheel. Have them set an 18" wheel size that is the closet match to your tires, that will be the best you can do.

Once they have thrown a CEL, like in your case, I believe the tech told me he needed to reset my PCM in order to clear it. It has been fine ever since.

 

I thought any size that would have been available for your truck from the factor (dependent upon your axle) would be a selectable size?

 

I recently upgraded from 18 to OEM 20. Dealer recalibrated the truck without issue.
Seems strange to me that the dealer said that axle ratio won't take the 20's.

I was doubtful that my upgrade would even work, but the dealer offered to test it out before I bought the OEM 20's. They said as long as it was an available OEM size then they should be able to recalibrate.

 

But do you probably have 3.55 gears?

 

So why does the wheel size matter to the computer? Isn't it ultimately about the tire circumference? Tire circumference translates to rotations per mile, regardless of the wheel-tire interface diameter.

I haven't messed with my wheels and don't intend to... so please excuse the dumb question... Just curious!

Carl

 

He has the 6.2L so probably 3.73 or above if I had to guess.

 

Thats kinda my thinking. As well.

 

I will put it this way if your truck had 17's on a diesel with 3.31 gears. And you put 20's on it. It would always be in a lug situation.so the engind rpm wont match the trans output shaft speed. Due to to large a tire size. Its called your. Roll out is way off. The pcm knows what gear is stock. So it knows if you try to go past a certain size it will screw up your trsns shift points, so it wont accept thst much of a change.

Now if it had 3.55 gears you would be able to get close. Thats one reason they dont give that much leway on tire size vs gears