My dealer says they are unable to flash the computer for 07 JKs (I have changed my tire size to 265/75 16 from the stock 225/75 16). Does anyone know of something (service notice?) I can point the dealer to?

Thanks,

Joe

 

Looks like they just need the right certification

 

Unfortunately, they are correct, DCX took away the capability of the tech to change your vehicle's computer for anything other than a stock, factory tire size. They can change it to the closest possible match though. Ask them to set it to the stock Rubicon tire size (255/75R17) and your speedo will be very close.

If they tell you they can't do this, find a new dealership

-E

 

So you are saying they can flash it? When I talked to them, we did not talk tire size. They just said that starting with the 06 model wrangler they could no longer update the speedometer for larger tires. My understanding from reading the forums is that they can update the computer for up to around 32 inch tires.
If this is the case, is anyone aware of some kind of documentation I can point them towards?

Thanks,

Joe

 

My dealership flashed my Jk for 265/75 16. It is about a 31" tire. They charged me $85 to do it but they did it.

 

You might be running into trouble saying they need to "flash" it. It doesn't involve flashing new code to the computer, it's just a setting change. Not sure how it's done, but it CAN be done.

-E

 

Has anyone bought one of these yet?

Superlift TruSpeed Speedometer Calibrator

Main Features:

Corrects speedometer / odometer readings, and the speed signal sent to the engine, Powertrain, and anti-lock brake control modules. Besides the obvious, these modules affect fuel delivery, engine timing, and automatic transmission shift points.
Eliminates speed signal related reductions in engine performance and fuel economy, as well as related changes in exhaust emissions
Infinite adjustability provides precise speed signal calibration within 1%
Two settings allow off-roaders that seasonally run different height tires to correct their speed signal by flipping a switch
Simple four-wire hookup
Includes complete instructions and adjustment charts
Can be recalibrated infinitely for future tire size or gear ratio changes
Works on most vehicles equipped with an electronic speedometer

It runs $185...I'd hate to spend cash on junk...but it would be nice to have my speedometer be correct.

I asked a dealer to change the settings on my Jeep to the 32" tire size--they didn't want to do it (not that they couldn't), so I didn't push the issue at that time. I'm running 285/70R16 BFG AT K/Os on stock rims. The diameter lists as 31.7--the 32" setting would get me really close; like within about a percent.

Has anyone bought one of these Superlift TruSpeed Speedometer Calibrators?

I found the link: ntwonline.com/acb/showdetl.cfm?&DID=48&Product_ID=1973&CATID=15 on a Jeep Club page.

 

I had mine flashed (new computer setting) to 255/70/18 tires with no problem when I asked the dealer. The Jeep runs much better with the bigger tires and setting. No charge.

 

That is exactly what I did and the dealer "flashed" mine to make it pretty close.
With the orig 225's, speedo was dead nuts as per GPS. With 265x75xr16 BFG AT's, it was ~8% off(speedo reads 8% slower than GPS), which happens to be the diff in tire circumference. For $50, had the dealer "flash" my speedo for the new tire size. They must have flashed it for something like a 31" tire, because now it is still ~2% off(reads 2% slower than GPS).

 

To my knowledge those will not work on the '07's. (I cannot 100% verify that, it is just what i was told by a local 4x4 shop that supposedly looked into it)