tpms on sreen accuracy

[oldbimmerguy]

I have 2 digital tire%gauge s and 2 analog. All 4 agree with each other within about 2 psi. However, the on vehicle screen tire pressure monitor reads low. In order to achieve the specified 33psi for fronts and 41 psi for rears I need to go 4-5 psi above that number on my other gauges. Now since they all agree with each other, it should seem the car is somehow reading low. I have performed 3 system resets and now have the exact specified numbed on my screen, but the rears for example check at 46psi with all my other gauge s. This is too high and the car seems to ride hard of course. I know such exact precision is not required for simple daily driving, but the stupid short life and high price/ poor selection of the 20 inch ecopia makes me want to treat them as well as possible.

 

[mojo]

Unfortunately the system on the i3 is a "direct" system, so as I understand it the in-wheel sensor transmits absolute pressures and temperatures (unlike an "indirect" system where the ABS controller calculates the pressure externally to the wheel). As far as I know there is no facility to correct the values within the DSC controller. I guess it's possible that the in-wheel sensors might tend to misread as the built-in battery ages, but that seems unlikely - most digital sensors don't work like that - they either send reasonably accurate readings or they stop sending anything at all.

The sensor's batteries are rated with a life of 10 years or 300,000 kilometers. If yours are approaching that, it may be worth considering replacing them - though at main dealer prices that won't be cheap. Non-OEM sensors are available, but I don't know what the quality of those is like.