The DTC is C0238 ( wheel speed mismatch). Yes on the 40 PPR. the speedo is acurate but still getting the DTC. Do I have to go to the dealer for the tech 2 change?Quote:
Originally Posted by EC_Tune
Mark
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The DTC is C0238 ( wheel speed mismatch). Yes on the 40 PPR. the speedo is acurate but still getting the DTC. Do I have to go to the dealer for the tech 2 change?Quote:
Originally Posted by EC_Tune
Mark
Yep. Tech 2 is the only thing that can reprogram your ABS module for the new tire size.
And you need them to put in a tire size close to the one you have on your truck.
The other solution is to put in the stock trans rev/mile value and make the speedo VSS Pulse/mile correct. All your shifting will be off as well as the reported speed with VCM Suite but you won't have the dash light (ABS related).
Attachment 12500 ok heres one of my tunes that i cant adjust the tire size please help my speedometer is going crazy
Quote:
Originally Posted by EC_Tune
you sir, are a gentleman and a scholar!!! thank you for your contributions
Tech 2 will only load a preexisting GM calibration - it will not modify the calibration. Changes to wheel and tires (sometimes a dealership upgrade) require a different calibration - some of these already exist - and are accessible via a VCI number.
As an example, the same applies to upgrading some newer vehicles to allow Cruise Control to function (which did not originally come equipped with Cruise Control). You call the GM Tech Line (have never found these folks very helpful) and if the calibration exists (i.e. was an option) - they will upgrade the VIN based calibration for your specific vehicle - and issue a VCI number to access this. All for a fee of course.
I know this is an old thread, but everything points back to here and I'm not sure if I'm doing this correctly. I made a slight change of tire size, just enough to put me about 2mph out at 60mph (not a big deal, but it bugs me). I went from 255/45r18 to 275/40r18. I used the spreadsheet and you can see the differences. However I'm not sure what all to change.
Do I just change the VSS tire revs per mile?
Attachment 42358
Also, I assume I manually scale the transmission as well?
Attachment 42359
Based off the calculation in the spreadsheet?
Attachment 42360
Am I missing anything else???
I know it's a necro-thread, but here's how I've delt with the dreaded C0238 and the speedo issues with my customers:
http://www.hptuners.com/forum/showth...The-Fix-Thread
Awesome wirte-up! however ive been having an issue because my current tire size is listed as error and the gear ratio at 1 and when I enter the new values the commit button stays ghosted. Ive searched but haven't found anything useful. if I have to manually calculate the revolutions that is ok but just wondering if any one has found a fix.
I found an equation for number of pulses this might help you.
https://www.circuitschools.com/wp-co...e-formula.webp
There is an online calculator too.
Source: https://www.circuitschools.com/pulse...ula-in-detail/