TPMS sensitivity

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BillB15

Member
:
Mazda CX5 GT 2014
During normal driving on my local roads, the TPMS warning light and audible alarm came on. The light stayed on while I continued to my driveway about 1/4 mile away. My first thought was a flat tire happening (as the system should warn about), but upon immediate tire pressure check, all 4 tires were set the same to around 38 lbs. I am very thorough keeping them at the prescribed 36 lbs. when cool, but these 2 or so lbs. raised by driving on hot road must have set the TPMS off. That is ridiculous. I followed the manual instructions to reset the TPMS and it remains reset so far.

I am beginning to miss my Honda more and more as the Mazda continues to demonstrate poor engineering and weak attention to details.
 
I wonder have you recently altered the pressures, but not reset the TPMS?
 
I have been driving in -10C (14F) to 30C (86F) temperature ranges without any false alarm on the TPMS.
 
First off, the factory recommended pressure is 34# (not36) and the TPMS only should function when the tire loses pressure, not when it gains! You may want to recheck your pressures (cold) with another guage (and reset the TPMS) to rule guage innacuracy out and, if it continues, I would have the dealer check it out. In 9 months of driving I have not found this feature to be overly sensitive at all. In fact, I am never even aware of it functioning.
 
Mine has gone off twice over small variances, I forget just how much but never an puncture.

paris1 said:
the TPMS only should function when the tire loses pressure, not when it gains!
Click to expand...

It goes off the difference in rotation speeds between the wheels so a greater gain in one tire could cause it to think the other 3 were off or a lesser gain in one tire would look like its pressure was dropping.

There are plenty I like about this system not having sensors on the wheel: reduced cost, no risk of damage when changing tires, no need to redo any programming when rotating tires. But at times I do miss having an actual readout of the pressure in each tire.
 
paris1 said:
First off, the factory recommended pressure is 34# (not36) and the TPMS only should function when the tire loses pressure, not when it gains! You may want to recheck your pressures (cold) with another guage (and reset the TPMS) to rule guage innacuracy out and, if it continues, I would have the dealer check it out. In 9 months of driving I have not found this feature to be overly sensitive at all. In fact, I am never even aware of it functioning.
Click to expand...

The 19" wheels are a 36 as per the door sticker. See the answer of HandA below as it is what the dealer told me after I spoke to him this afternoon. The ABS system has a sensor to detect rotational value differences of the wheels and it indeed has been brought to the dealer's attention multiple times how sensitive it can be. Furthermore, it is a learned rotational value in the CX5 and if you set your tire pressure to 50 lbs. in each wheel and go through the reset procedure as described in the manual, it will think 50 lbs. is the prescribed value. This allows for the use of different tire varieties and their own unique pressure needs. Also of interest is that if you drive about 50 miles at the new settings, it will be more permanently ingrained in the ABS sensor memory and the car then needs to be "factory reset" and the dealer informed me this is a 2 hour procedure that also involves them sending a technician out for another 50 mile drive to unset your "bad/unusual" reset value.
 
Same thing happened with mine a week ago when we had a bit of a heat wave. It never went off during the winter and I never messed with the tire pressure at any time. I let the tires cool down, checked the pressures, reset the tpms, and been driving for a week now with no problems.
 
Question do you folks have regular air in your tires or was it nitrogen filled from the dealer
 
Regular air. There have been tests on various nitrogen tire fill stations and whether or not they are true nitrogen and are effective. Many were proven to have same changes in association to temp that is similar to regular atmosphere air pumps (1 psi change to every 10 degrees).
 
I find the factory reset claim hard to believe.

If it works like that the dealers would be getting lots of calls.
Every time I tow the cars pressures are increased, so based on what the dealer has said I will be %ucked when I come down to normal pressure again.

BillB15 said:
The 19" wheels are a 36 as per the door sticker. See the answer of HandA below as it is what the dealer told me after I spoke to him this afternoon. The ABS system has a sensor to detect rotational value differences of the wheels and it indeed has been brought to the dealer's attention multiple times how sensitive it can be. Furthermore, it is a learned rotational value in the CX5 and if you set your tire pressure to 50 lbs. in each wheel and go through the reset procedure as described in the manual, it will think 50 lbs. is the prescribed value. This allows for the use of different tire varieties and their own unique pressure needs. Also of interest is that if you drive about 50 miles at the new settings, it will be more permanently ingrained in the ABS sensor memory and the car then needs to be "factory reset" and the dealer informed me this is a 2 hour procedure that also involves them sending a technician out for another 50 mile drive to unset your "bad/unusual" reset value.
Click to expand...
 
I love the TPMS feature. After 9,600 miles not a single complaint.

I think those who are not satisfied do not set their tires to the same pressure very closely before resetting the TPMS system. This could be due to inattention to detail or using a pressure gauge that is inconsistent. The market is full of very cheap pressure gauges. Even with a good gauge it is necessary to use good technique to insure accurate results. A pressure difference of .75 psi might not sound very significant but it amounts to a 2% difference in pressure.
 
Funny that I see this thread just when I am starting to experience the problem.
Full disclosure: I had my car serviced on Saturday (which included a tire rotation), didn't do much driving on Sunday, and about 50 miles on Monday.
Problem: Occurred on Tuesday evening, TPMS alarms went off, tires not flat, so I checked the pressure; all 4 at around 32 (a little low but not threatening). I reset the TPMS to see what would happen. Next trip out it came back on. So I Filled up tires to 38psi so I could check today if any of them lose pressure overnight. TPMS alarm went off on my way to work. I will check the pressure again and lower it to 36psi on each and reset the TPMS again before I leave work. Hopefully it doesn't go off again. If it does, I'm going to ask the dealership what they #@!$ they did when they rotated the tires on Saturday.
 
Jcanracer said:
Full disclosure: I had my car serviced on Saturday (which included a tire rotation), didn't do much driving on Sunday, and about 50 miles on Monday.
Problem: Occurred on Tuesday evening, TPMS alarms went off, tires not flat, so I checked the pressure; all 4 at around 32 (a little low but not threatening). I reset the TPMS to see what would happen. Next trip out it came back on. So I Filled up tires to 38psi so I could check today if any of them lose pressure overnight. TPMS alarm went off on my way to work.
Click to expand...

If you have described the above scenario correctly your TPMS is working normally but you (and your service "technicians") are using it incorrectly.

First time the TPMS alerted: The tires were rotated but apparently the TPMS was not reset. This is mandatory after a tire rotation (even if all four tires have approximately the same pressure).

Second time TPMS alerted: The TPMS was reset without changing the pressure from the last alert. The tire pressures must be adjusted after a TPMS alert before the TPMS is reset. It's all in the owner's manual.

Also, the manual does not mention this explicitly (it only mentions tires should be cold), but it is important to not perform a TPMS after some of the tires have been warmed by the sun.

My experience has been that, after a proper reset, the TPMS will not create false alerts.
 
Ironically... just yesterday afternoon had the sensor go off for the first time.

Checked all four and my front left was two lbs higher than the other three (sitting at 38 cold). Based on this, it did notice my tire pressure had "increased".
 
In the service manual it indicates that the TPMS has a "reset in error" cycle that may require three resets in order to learn a new "normal" pressure level. The net is you may have to reset it three times to learn a new correct level. I think sun on one side or one tire while the others are in the shade is the biggest problem as that will create an unbalance in pressures. If all tires go up in pressure or down in pressure it should not alarm as it counts the relative difference in rolling rate while driving straight at a constant speed.
 
GAXIBM - Good info, thanks. I had similar issue during a heatwave here (temps over 95 degrees F). I reset it 3 times before it went away, not knowing about what you found in service manual. Btw my tire pressures are consistently set about 1 pound over recommended pressure per label (cold).
 
GAXIBM said:
In the service manual it indicates that the TPMS has a "reset in error" cycle that may require three resets in order to learn a new "normal" pressure level. The net is you may have to reset it three times to learn a new correct level. I think sun on one side or one tire while the others are in the shade is the biggest problem as that will create an unbalance in pressures. If all tires go up in pressure or down in pressure it should not alarm as it counts the relative difference in rolling rate while driving straight at a constant speed.
Click to expand...

This seems to be the case, I reset the TPMS yesterday before leaving work and it have not come back on yet.
 
SayNoToPistons said:
Regular air. There have been tests on various nitrogen tire fill stations and whether or not they are true nitrogen and are effective. Many were proven to have same changes in association to temp that is similar to regular atmosphere air pumps (1 psi change to every 10 degrees).
Click to expand...
Was just curious, as mine came with Nitrogen but in the event I get a flat I am putting regular air in there I refuse to pay for something I don't have to
 
The biggest reason for nitrogen on street cars (excluding track/race cars) is because compressed air has moisture which increases the chance of rotting on the inside surface of the tire and wheel. Unfortunately like I previously mentioned, the equipment and results for nitrogen filling stations are so uncontrolled that it is not worth the extra effort and money to obtain an attempt at filling tires with nitrogen as it is not true nitrogen.
 
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