Flat tire and No TPM light came on

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2019 CX-5 Signature
I haven't driven the car since last week and I pulled out the driveway and noticed my car's wheel was awfully close to the ground. It was low.

There were no lights this morning when I started the car up.

I thought this was a pressure based system.
 
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2017 CX-5 GT AWD
I believe it is a 'rotation' based system, or whatever that would be called. I think the car has to sense from the TPMS that the rotations are faster on one tire than the rest and that is how it alerts. Sorry, don't know the technical terms. I'm sure someone else can elaborate on this! So since you weren't actually driving, no alert.
 

sm1ke

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'18 CX-9 Signature
What was the PSI of the low tire, and what was the PSI of your other tires? Are you on OEM wheels and tires?
 

sm1ke

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'18 CX-9 Signature
I believe it is a 'rotation' based system, or whatever that would be called. I think the car has to sense from the TPMS that the rotations are faster on one tire than the rest and that is how it alerts. Sorry, don't know the technical terms. I'm sure someone else can elaborate on this! So since you weren't actually driving, no alert.

This is true for "indirect" TPMS systems. The new CX-5, however, uses "direct" TPMS systems, which operate based on individual sensors within each tire relaying a signal to the car. https://en.wikipedia.org/wiki/Tire-pressure_monitoring_system

On a Mazda, you can tell which system you have by seeing if you have a TPMS Reset button somewhere on the dash. Those with the button have indirect TPMS. Those without the button have direct TPMS.
 
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2019 CX-5 Signature
...

On a Mazda, you can tell which system you have by seeing if you have a TPMS Reset button somewhere on the dash. Those with the button have indirect TPMS. Those without the button have direct TPMS.

My Lexus has the button, but it also shows each tires actual pressure when called up. Besides not being able to display actual pressure values, what is different with Mazda that it doesn't need a reset button?
 

sm1ke

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My Lexus has the button, but it also shows each tires actual pressure when called up. Besides not being able to display actual pressure values, what is different with Mazda that it doesn't need a reset button?

It may have to do with differences in each manufacturer's TPMS Reset procedure. I know that with the indirect TPMS on a Mazda, pressing the button saves the current pressure (i.e. the diameter of the current wheel inflated to XX psi) as "normal". If the wheel happens to become a smaller diameter by X%, the warning light triggers. This means that you could probably deflate all tires to 5 psi, reset the TPMS, and the light might never come on because the wheel diameter doesn't decrease enough to trigger the warning. With Mazda's direct system, the "normal" psi is factory-set, and (I think) can only be changed by the dealer. The difference between your Lexus and the CX-5 may simply be the ability to configure the "normal" psi to whatever you want by using the button. IMO the direct system is more expensive, but it's also a little bit more "idiot-proof".

A few other things to note that may have caused the TPMS light to fail to illuminate: http://www.mazda.ca/en/digital-owners-manual/2018/cx-9/contents/05120201.html
 
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2019 CX-5 Signature
It's a 2019 CX-5 signature with no button for TPMS reset.

I plugged in the inflator and it read 5 psi. All the other tires should have been around 35 psi. I did not measure the other tires but they were not flat.

I brought it to a tire shop and they patched it. They found a nail.
 
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92 MX-3; 18 CX-5
Here's the deal: TPMS sensors do not continuously report tire pressure. Your 2019 includes an actual pressure sensor in each wheel. It is part of the valve. But in order that the small battery inside the sensor last for about 10 years they are not continuously reporting. I'm kinda surprised that the system does not report on start up - if it had you would have gotten a warning. All systems report at some interval while you are driving.
 
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2017 Mazda CX-5 GT, 2016 Mazda6 iGT, 2014 Mazda3 sGT hatchback
I think it will report once the vehicle starts to move. That sounds stupid, but it is like that if your tire lost air while parked.
The device saves power by reporting only periodically and more than certain minimum speed.
 
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2019 CX-5 Signature
I think it will report once the vehicle starts to move. That sounds stupid, but it is like that if your tire lost air while parked.
The device saves power by reporting only periodically and more than certain minimum speed.

That makes sense.

I just bought the Orange Electronic TPMS monitor. A major oversight of Mazda of not including TPMS in the infotainment. I think the CX-3 has it.
 
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2019 CX-5 Signature
Is the Mazda AIO still actively being developed? I always wonder what kind of data is actually exposed. Is the TPMS pressure data accessible?

I think I looked at their GitHub page a while back and didn't see anything there.
 

sm1ke

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This note is from the link I posted (links to a CX-9 manual, but they use the same sensors):

To avoid false readings, the system samples for a little while before indicating a problem. As a result it will not instantaneously register a rapid tire deflation or blow out.
 
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2017 Mazda CX-5 GT, 2016 Mazda6 iGT, 2014 Mazda3 sGT hatchback
I had experience when my rear left tire got punctured by a bolt at highway speed. The pressure dropped very quickly within seconds. The light went on with beeps to go with it. This was with '08 CX9 which has TPMS sensors inside the tires.
i.e. when car is moving the sampling period is fairly short (a few seconds) I would guess.

Another time, the tire went flat while sitting in my garage because of a nail.
The TPMS light lit up while the car was moving out of garage, not at startup of engine.
Same CX9.
 
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2019 CX-5 Signature
I had experience when my rear left tire got punctured by a bolt at highway speed. The pressure dropped very quickly within seconds. The light went on with beeps to go with it. This was with '08 CX9 which has TPMS sensors inside the tires.
i.e. when car is moving the sampling period is fairly short (a few seconds) I would guess.

Another time, the tire went flat while sitting in my garage because of a nail.
The TPMS light lit up while the car was moving out of garage, not at startup of engine.
Same CX9.

Wow mine didn't even notify me when moving out of the garage. I moved at least 30 to 40ft.
 
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2019 CX-5 Signature
With the Orange TPMS monitor, the wheel pressures don't immediately measure. I think the sensors only report after the car moves a good 10 seconds. I wonder if it is woken up by speed.
 
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2016.5 CX-5 GT AWD titanium/black 2016 Miata Club ST MT white
My Kawasaki motorcycle has direct TPMS and here's how that system works, I'm fairly certain that most, if not all, TPMS work the same way.

The pressure sensors do not continually broadcast pressure data, the batteries wouldn't last long if they did. The sensors 'wake up' by the rotation of the wheels and then they can broadcast data. Some systems, including Kawasaki's, also read temp and adjust the pressure reading accordingly.

PV=nRT
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
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Plano, Texas, USA
My Kawasaki motorcycle has direct TPMS and here's how that system works, I'm fairly certain that most, if not all, TPMS work the same way.

The pressure sensors do not continually broadcast pressure data, the batteries wouldn't last long if they did. The sensors 'wake up' by the rotation of the wheels and then they can broadcast data. Some systems, including Kawasaki's, also read temp and adjust the pressure reading accordingly.

PV=nRT
Ha, havent seen
1f59f6195da1eadbfc33124aa89dd3fc8d9eefe1
the ideal gas law, for very long time! Mazdas current direct read TPMS system on CX-5 looks exactly like previous ABS sensor TPMS system with only a TPMS warning light. The TPMS pressure sensor in the valve stem actually reports both tire pressure and temperature, but Mazda simply chooses not to display them. Its kind of a waste with a more expensive direct-read TPMS system but doesnt make its very useful data fully presented to driver on CX-5.

IMO OPs TPMS system may have problem on that particular pressure sensor inside of flat tire. The system should work like ceric described.