Odometer reading question

I have had no luck getting this question answered. Can someone please help? I would like to know if the odometer reading on a 2014 or newer Tundra is only stored on the instrument cluster, or if the data is stored in the BCM, ECU, etc.
The reason: I am thinking about installing much larger tires and a Hypertech Speedo Calibrator. I want to make sure that if I do so, that the odometer reading on the dash doesn't end up being different than that stored elsewhere, if it is.
All I really need is for someone running a calibrator and that has access to TechStream, is to tell me if their dash reading matches exactly to what TechStream reports when you connect via the OBDII port.
I have asked this question here and well as other sites and it seems to be a pretty easy thing to verify. Could someone please help me out?
Please,
Jerry

 

It's in the ECU, you can see the mileage in techstream. It will be the same as what's read on the dash.

 

Do you know this for sure? I have been told that techstream reads it directly from the ECU and have been told from the instrument cluster. I have also been told that the IC sends the info it gathers from various sources and then sends that info to the ECU. I have looked at the diagrams on how the calibrator intercepts the signal and it ties into the CANBus network, so I'm not sure.
Your answer seems plausible but I would really like to have it confirmed with someone that has the calibrator and has seen their mileage readout in techstream.
Basically I see this going one of two ways. Either the ECU sees the mileage before the IC does, or it sees it after. If the signal is being intercepted by the calibrator, then there could be room for error in the stored data on the ECU vs the IC.
I really want to make sure the data matches before I go and add the tires and calibrator.
I appreciate the info though.

 

Everything that happens on your truck happens because the ECU tells it to or sends it information. The odometer is not like years past where the MPH was literally taken from the transmission and a wire drove a mechanism in your dawn that showed speed and distance. Whether you have a piece of equipment to intercept a signal it still doesn’t store anything. All it does is adjust the signal that it send to the ecu so the ecu sees what it considers a normal signal and than passes it on so you are able to see it on your dash. All the interceptor does is adjust the signal that comes from your speed sensors and adds or subtracts to that signal for the ECU.

 

I understand how the calibrator works. What I am not sure of is what all modules store odometer info and how those modules share the info. I know my way around vehicle systems but I don’t know the specifics of this scenario. We can all theorize but until I see a truck with a calibrator installed that has the mileage accurately reported in techstream I won’t be satisfied.
No offense.
Take for example the newer tundra where the cruise control set speed is displayed on the IC. With a calibrator installed the Speedo displays the corrected speed yet the digital set speed displays the unadjusted speed which means the calibrator is not intercepting and changing all required values which concerns me. Of course mine doesn’t have the digital set speed displayed since it’s a 2015 but you see my point

 

Maybe I can answer your question if you know if it would read the same value as the Bully Dog would. I am not familiar with the techstream software(never used it) however, if it connects via OBD port like the bully Dog programmer does then no it won’t match. I am calibrated and used to leave my bullydog installed. The BD displayed the original MPH while the dash shows calibrated.

 

Thanks George. I appreciate that. Your info reinforces my concern.

 

No problem. Hopefully somebody can chime in that can verify with techstream info for sure. I guess it would be possible for the odometer signal to not be adjusted by the Hypertech on it’s way to the dash but with no schematics or anything it would just be speculation. I am personally not concerned if they don’t match because I doubt anybody would ever pull the odometer from the software.

Random thought maybe somebody could look at their mileage then disconnect the hypertech then turn the key and check the mileage again. Maybe that would verify what’s in the ecu.

 

Just wondering if anyone has looked into this yet with their TechStream......