Hi
We have OVMS for our Smart ForTwo 453 (EV).
In the app we are constantly receiving tyre pressure notifications even though the tyre pressures are correct.
The problem seems to stem from the fact that the rear tyres are larger and required more pressure (38/39 PSI) and the fronts need (32/33 PSI).
However when we look in the app, the Drivers side (Right) tyre pressures are the wrong way round. It showing the Front pressure for the rear tyre and vice versa.
We initially though it might have just been that the wheels got swapped during our last tyre change, but this is not possible as the wheels themselve are a different size. The back's are wider than the fronts, so there's no way they got mixed up (and to verify I have just had the car into the garage for them to check everything out).
So it points to a bug in either the OVMS App or firmware reporting the wrong pressures.
Is this a known issue? Anything we can do to resolve it her?
One possibility: Code changes caused this.
In the past 6 months or so, TPMS handling code has been modified, allowing the User to manually change tire positions for some vehicle types. This is implemented for THINK City and I believe also for the Smart EVs. If you have TPMS enabled in the App, check this by:
1) Select Controls, then TPMS
2) Touch and hold the displayed tire data for one of the tires that needs swapping (e.g. FR or RR) until a toolbox pops up with radio buttons allowing you to reassociate that wheel (e.g. FR to RR). Repeat for the other tire to swap it to the other tire.
I think you can also select these in the OVMS Webpage UI.
Anyway, give this a try.
In the case of THINK City, the TPMS sensors are "learned" after pressing and holding a button in the fusebox. Then the User drives the car around for awhile and at that point, if the pressures all match specs, the dash light goes green. It's been my contention that there's no way the car can tell right from left because, as you described for the Smart, there's only a pressure difference spec'd for front vs back. And so, with this ability to manually change this orientation really is useful.
If I'm wrong with any of this, hopefully someone will correct me.
-Myles