2019 Tacoma speedo/odo calibration

Waiting on Hypertech to add support for the 2020 as well, but since they haven't even done the 2019 yet, I'm not holding my breath.

 

Yep, California's motto: If we can't tax it out of existance, we'll regulate it out of existance.

 

https://www.roughcountry.com/speedo...=2019-toyota-tacoma-4wd-374230&sid=0pZAoLJKO3

Says change shift points too Anyone confirm this works as well and works well?

 

Mine's a manual, so obviously this doesn't apply to me. But I'm quite certain it doesn't do that on an auto. I'm actually quite skeptical if it even corrects the odometer. The only thing I can say for sure is that it corrects the speedometer (by comparison to my gps data, using the same app before and after installation). My adaptive cruise control is way off - if I set it for 70, the cruise will keep me at 75. Also, my gas mileage reading has not changed at all since installation (doing approximately the same type of driving) - with a corrected odometer, my mpg should read about 1 mpg better than before...
I'm going to do a test at some point, take the exact same route to work, with and without the device installed, read my odometer before and after. I have a 22 mile commute, so I should be able to see about 3 miles difference in a 44 mile round trip (my tires are 285/70r17, 6.8% larger than stock)

 

That would be great @benkitesurfs Look forward to buying you a beer.

 

I can see it affecting AT shift points as one of the sensor inputs is speed. If the speed is wrong due to gearing or tire sizes, then the shift points will be off comparatively. That is based on the assumption that the ECU shift points were set at indicated speeds without errors.

 

The problem is, I think the device only affects the speed input to the gauge cluster - I think the ECU is picking up speed before the signal gets to the gauge cluster. Somehow my truck is still getting an inaccurate speed reading for the cruise control system, so it must be picking that up before it gets to the gauge cluster...

 

Good point! I agree that if it only affects the instruments after the ECU, then there should be no effect on anything else. That is unfortunate given the cost.

 

AND my local dealer never called me back about doing a speedo/odo calibration. Excellent!

 

Especially when it doesn't check out lol. Tires may have a defined diameter but notice that the bottom deflects - this reduces the effective diameter of the tire and is what induces rolling resistance. You can't use tire diameter to accurately measure speed, all you can use it for is a guideline.

Jeep and Dodge used to allow reprogramming with the factory tool and we used to have to tweak because they were frequently off 1-2% based on load range, air pressure, vehicle weight...

 

If you're just trying to return the system to stock readings, the tire size is good enough. Whatever calculations Toyota did with 265/70r16s resulted in the stock configuration. Whatever minimal effects bottom deflection has on the stock tire effective diameter will also apply to the new tires. A simple 6.8% adjustment should bring my truck with 285/70r17s back to stock readings. Its absurd that Toyota wouldn't include a way to do this, knowing that changing tire sizes is very common on these trucks.

I'm curious if @OVTune has a solution to this problem...

 

Toyota is a conservative company and it's a liability for them to make the change. OEM calibration has to be within a certain range and if the dealership makes that change, they need to make sure it's still reasonably close. By requiring a third-party module, Toyota has relieved them self of all liability.

I've seen Jeeps as much as 4-5% off or so using a tire OEM spec when I wrenched. We used to take a Garmin on test drives for recalibration and the shop rule was no more than 1mph off at 70 between the GPS and scan tool readout so we'd tweak until we hit that mark.

The factory calibration assumes a P-rated tire which has a much weaker sidewall and overall rigidity than an E-rated LT tire. It's not as simple as "add 6.8%" on most of the OEM tools, you manually enter the tire size or revs/mi and it makes all kinds of assumptions as to tire pressure and deflection from that.

 

Absolute truth.