TPMS reset on 2023 CX-5

[paris1]

So we purchased a new CX-5 Premium trim over the weekend and I checked the tire pressures after getting it home. Like all Mazdas I've had in the past, it was delivered with overinflated tires, so I adjusted them to the proper spec and now I'm confused about resetting the TPMS. On my old (2013) CX-5 and current 2018 Mazda 3, there is a TPMS button on the dash, so the reset is pretty straight forward. The new cars apparently have a semi-automatic reset function, but the owners' manual is a bit vague as to how to activate it. Can someone clarify this for me?

 

[HyFlyer]

I believe (if it's like my 2019) there is nothing to reset with a pressure change. The new systems use in-wheel transmitters. (Your 2013 and 2018M3 used the ABS system wheel sensors is why they needed reset with pressure change).

 

[paris1]

I believe (if it's like my 2019) there is nothing to reset with a pressure change. The new systems use in-wheel transmitters. (Your 2013 and 2018M3 used the ABS system wheel sensors is why they needed reset with pressure change).

Yes, I know it's a different system. According to the manual, you're supposed to turn the ignition on and then off after making any changes. Then wait 15 minutes before driving it for 10 minutes, which then resets the system. All that seems rather strange and I'm not sure how necessary it all is.

 

[Sig cx-5]

Yes, I know it's a different system. According to the manual, you're supposed to turn the ignition on and then off after making any changes. Then wait 15 minutes before driving it for 10 minutes, which then resets the system. All that seems rather strange and I'm not sure how necessary it all is.

It's not.

 

[RedBaron]

Once you drive for a short while, it will re-read the sensors.

 

[paris1]

OK-thanks! Does it give you any signal that it's successfully reset? Like a "beep" at some point.

 

[Jmaz]

I believe (if it's like my 2019) there is nothing to reset with a pressure change. The new systems use in-wheel transmitters. (Your 2013 and 2018M3 used the ABS system wheel sensors is why they needed reset with pressure change).

I never have reset TPMS on my 2014 after pressure adjustments including the seasonal pressure adjustments. Could this be why when I once had a loose valve stem core and the light didn't trigger until the pressure dropped to 20 PSI. Naturally I reset it after airing up. That's the only time the light ever came on.

 

[HyFlyer]

@Jmaz , my understanding of the system on your 2014 using the ABS system wheel speed sensors is that since it doesn't directly sense the actual pressure, all it's doing is comparing the rotation of each tire against the others. A low pressure tire will have a slightly smaller circumference so will roll a slightly faster speed than the rest. The system is just picking up on that difference.

What you are doing by pressing the TPMS reset button on those systems is telling the control unit "THIS" (current tire pressure right now) is the correct pressure. If you pressed the button with 15 or say 55 psi in the tires, it would drive around happy with the TPMS light off at those pressures since it was "told" that was normal.

 

[paris1]

@Jmaz , my understanding of the system on your 2014 using the ABS system wheel speed sensors is that since it doesn't directly sense the actual pressure, all it's doing is comparing the rotation of each tire against the others. A low pressure tire will have a slightly smaller circumference so will roll a slightly faster speed than the rest. The system is just picking up on that difference.

What you are doing by pressing the TPMS reset button on those systems is telling the control unit "THIS" (current tire pressure right now) is the correct pressure. If you pressed the button with 15 or say 55 psi in the tires, it would drive around happy with the TPMS light off at those pressures since it was "told" that was normal.

That's correct, but how does that compare to the newer system? When I reset the pressures from 39 to 35 psi, are the sensors in each wheel telling the control unit that 35 is now the desired pressure, or is the controller comparing each wheel's reading to the value it knows to be correct (in this case 35 psi)?

 

[HyFlyer]

Each in-wheel sensor transmits actual tire pressure (and temperature). I imagine the "brain box" in the car has hard low/high psi numbers programmed to trigger the light outside of a range.

 

[Jmaz]

@Jmaz , my understanding of the system on your 2014 using the ABS system wheel speed sensors is that since it doesn't directly sense the actual pressure, all it's doing is comparing the rotation of each tire against the others. A low pressure tire will have a slightly smaller circumference so will roll a slightly faster speed than the rest. The system is just picking up on that difference.

What you are doing by pressing the TPMS reset button on those systems is telling the control unit "THIS" (current tire pressure right now) is the correct pressure. If you pressed the button with 15 or say 55 psi in the tires, it would drive around happy with the TPMS light off at those pressures since it was "told" that was normal.

Thanks for getting back to me. I always liked that the wheel speed sensors were being used so there was less complication (and expense) compared to individual pressure sensors inside the tire. On that note, I remember reading about people having a TPMS light that wouldn't go out after adjusting and resetting. This was on systems (not CX-5's) that didn't indicate individual tires, just that it detected a tire pressure out of spec. Turns out the spare tire which never got aired up had a sensor and was low on pressure.
Your answer confirms what I suspected after reading what you posted above in that the reset 'locks in' the correct pressure for the computer to reference. I wonder exactly what pressure the computer was using as a reference since I had the car for about 6 years and many pressure adjustments until the light was triggered. So it goes. Ain't technology great!