I have a 2016 Prius Touring model with the digital speedometer. Is there a setting in any of the car's ECUs that I can change (and write) for "Speedometer Correct Factor"? Since I changed the tires, the speedo readout is about 4% lower than my phone's GPS says (Example: 55MPH speedo v. 53.5 on GPS. 77MPH on the speedo v. 74.5 on GPS). It's always been a little off even with the tires that came new with the car (I bought the car new from the dealer), but now it's bugging me. I have an OBDLink OBD2 adapter and their OBDLink app with its 2016 Prius enhanced package. From what I can tell, the app is getting speed from the tablet's GPS and not the ECU - it matches my phone's GPS reading and not the speedo readout. Or, is there a screen that I can look at on the car's LCD display that will do this?
Well, I can see this was beat to death on this other thread. But on a Gen3. I presume it's the same for a Gen4. If you sort through the "... it's a government conspiracy" posts, it comes down to "It can't be changed". I guess I'll just use my OBD2Link Bluetooth OBD2 adapter to my 7" Android tablet with the OBDLink app and mount it on the dashboard as a HUD to see what its GPS reads while I'm driving.
You can get a cheap GPS speedometer off of Amazon for about $15. Mine has a 3/4 inch bright display and plugs into a USB port.
I don't want to leave my expensive phone on top of the dashboard of a hot car as thief bait. Even if you install the phone and program if for the speedometer ap every time you get in the car, and then remove the phone and take it with you every time you leave, that's a lot of time wasted and an endless hassle. The GPS speedometer never needs any attention or programming. It s automatically turns on and turns off. Almost no one knows what it is. Even if stolen, you'd lose only a measly $15.
To any and all, you could just keep in mind, with stock tires, that if the speedometer shows say 30 mph, you’re actually around 28~29 mph. Or just forget about it, accept that you’re going one or two blessed miles per hour slower than displayed?
