TPMS Question

[Tccox]

OK checked my tire pressure for the first time today(OK, car is two months old. I was lazy, I know) No TPMS warning light has ever come on but pressures were all way low, in the 26-28 PSI range in stead of the recommended 36PSI. Question why did I not ever get a warning light???

 

[mazdadude]

OK checked my tire pressure for the first time today(OK, car is two months old. I was lazy, I know) No TPMS warning light has ever come on but pressures were all way low, in the 26-28 PSI range in stead of the recommended 36PSI. Question why did I not ever get a warning light???

Since there is no pressure monitor inside the tire anymore, the TPMS works by calculating the rolling circumference difference of a low tire when compared to the rolling circumference of the other 3 tires. "Which one is not like the others..."

In order for the TPMS system to work, the initiate or reset procedure must be done correctly with ALL the tires at the desired PSI.


However there are several things the TPMS does not detect...

if the TPMS was initiated or a RESET was performed when the tires had incorrect pressures... it will be calculating based off of the incorrect pressures.

if all the tires go down in PSI over time due to natural air loss, or cold weather temperatures, it happens across ALL the tires evenly.


The proper way would be to inflate and adjust all tire PSI's as desired, and then perform the TPMS reset procedure.

Always try and adjust the tires when they are all at the same temperatures, preferably not driven and cold. If one side of your car has been heated by the sun, and the other has been shaded all day, you will have different PSI's on each side of the car.

The general rule of thumb for air temp to tire pressure, is 10 degrees F of ambient temperature equates to 1 PSI.

FOR EXAMPLE: So if your tires were filled to 35 psi at 90 degrees F in the summer, then comes winter, and at 40 degrees ambient, that will equate to around a 5psi loss to around 30psi.

 

[Tccox]

Thanks, guess I was confused because the BMW it replaced did have the sensors in the tires.

 

[mazdadude]

Thanks, guess I was confused because the BMW it replaced did have the sensors in the tires.

Yes it is not as helpful as the older individual sensor in the tire TPMS system, but the key advantages with the Mazda's sensorless system are COST, weight savings, and long term reliability.

 

[pinnieleakh]

Is it necessary to do it ?

 

[bmninada]

Question: will this sensor actually tell me which tire is low or just that some tire's low?

 

[mazdadude]

Question: will this sensor actually tell me which tire is low or just that some tire's low?

No, it will not point to a tire for you, you are in charge of checking your tires and using your eyes or a tire gauge to check that you are at your proper pressure.

Do not forget that you have to reset the TPMS after you adjust any of your tire pressures.