[plepak]

My TPMS alert went off today, and I found that the right rear tire was a few PSI lower than the left rear. However, it was actually still above the recommended PSI. Because the pressure information is inferred from the ABS sensors, I'm not sure exactly how it's determining the pressure. Is it somehow calibrated to figure out the actual pressure, or is it simply monitoring for a difference between left and right tires?

 

[anchorman]

It's a nice system on the CX3. Unlike others that have electronic sensors that need tuning to the system, once initiated, our system just derives a difference in wheel speed that a low pressure has on the rolling radius. I've got some interesting PDFs but yes, you've guessed it, the upload limit is too small. I can email you something if you pm me your email address.

 

[inflex]

I think the system detects a low pressure tire by sensing a difference in speed.

 

[plepak]

Thanks a lot, anchorman. We're entering the time of year marked by cold mornings, hot afternoons, and false TPMS alarms.

 

[OneLyveWyre]

Anchorman, would you please email me the TPMS information?
[email protected]

Thanks!

 

[LoneStarS30Z]

I have a question about TPMS. Having never owned a car with the system, what happens if you use something other than the factory wheels? I'm shopping CX-3's and CX-5's, and plan on swapping the OEM wheels with wheels from a R3 or Spirit R RX-8.

 

[seadawg46]

I have a question about TPMS. Having never owned a car with the system, what happens if you use something other than the factory wheels? I'm shopping CX-3's and CX-5's, and plan on swapping the OEM wheels with wheels from a R3 or Spirit R RX-8.

Most vehicles with TPMS will light and keep lit the low pressure warning light if you install wheels/tires without TPMS sensors installed. I'm not familiar with the Mazda CX3 system as this is my 1st Mazda vehicle so it may function differently.

 

[JPA]

CX-3 has a passive TPMS. It monitor wheel speeds using ABS sensors.
There are no sensors inside wheels/tyres.

 

[CX-ME]

I've hit bumps on the highway twice causing the TPMS to go off. In one case the light stayed on and I had to turn off the TOPMS and restart. The second incident it only briefly flashed on the dash and sounded.

 

[anchorman]

TPMS pdf attached.

OK, I’ve now been able to upload pdf’s to the forum. These are for your personal use only.

 

[inflex]

Anchorman, do you have some information on the TPMS trip thresholds?

At ~80 miles and just now at ~2500miles, my TMPS warning went off, with what seems to be false positives.

The first time, I pulled over, verified visually that no tires were completely flat and drove on. The next day, I checked the cold tire pressures and all tires were 35psi. Subsequently, I reset the TPMS and drove off. I assumed the warning was perhaps due to the dealer not calibrating the TPMS the first time.

Today, my TPMS warning went off again after about 20 miles of freeway driving. I immediately pulled over, checked the tire pressures, and each were at approximately 38psi.

What could be causing the warnings to trigger?

 

[anchorman]

If you look at the attached pdf you will see that in operation, the system is fairly robust. However, there is a mis-use prevention function that will throw up regular warning lights. To start, the system is initialised after say changing wheels. The system then goes through 20 minutes of learning what is normal. If a pressure loss is detected it will put the light on as designed. If the system is then initialised, it will detect that somebody is trying to run with a tire deflated and keep sending intermittent warnings. Maybe the system was initialised more than once and it now thinks there is a problem when there isn’t. The pdf suggests that the only way to clear the mis-use warnings is with the Mazda diagnostic tool. There is usually a work around but I can’t access the manual without paying and in that case I like to sit for an hour to get some VFM!

I would try disconnecting the battery for about 20 minutes to let all residual devices power down then after re-connecting, initialise the system again. If that doesn’t work, you’ll have to call at the dealer and let him re-set it until I get time to trawl the manual.

 

[CX-ME]

Cheers, Anchorman.

I'm off to the Mazda dealer tomorrow AM to have it looked at with said diagnostic tool.

 

[CX-ME]

I went to dealer on Thursday. Service tech ran Mazda diagnostic and said there nothing to worry about, could have just been cold weather (though it was in the 60s F when the first incident occurred). Anyway, tire pressure is fine in all 4 wheels. Tech said if it happens again and light stays on, leave it on and come back to the dealer.

The also looked at City Brake/Smart City Brake/ Forward Obstruction Warning via Mazda Diag. and said, again no issues. I had been concerned since there are always idiots in front of me stopping suddenly for no apparent reason on highways and such but the proximity warnings fail to sound and the auto-braking fails to engage. The tech suggested I'm further away than I think I am. Perhaps with the long front hood that's the case.

 

[anchorman]

I went to dealer on Thursday. Service tech ran Mazda diagnostic and said there nothing to worry about, could have just been cold weather (though it was in the 60s F when the first incident occurred). Anyway, tire pressure is fine in all 4 wheels. Tech said if it happens again and light stays on, leave it on and come back to the dealer.

The also looked at City Brake/Smart City Brake/ Forward Obstruction Warning via Mazda Diag. and said, again no issues. I had been concerned since there are always idiots in front of me stopping suddenly for no apparent reason on highways and such but the proximity warnings fail to sound and the auto-braking fails to engage. The tech suggested I'm further away than I think I am. Perhaps with the long front hood that's the case.

Good stuff. Regarding the SCBS, it only works between 19mph and 2mph and less than 20ft. Thats less than one and a half CX3s in front which will feel very close at 19mph!

Ive attached a detailed pdf which gives all the detail on how the system works.

 

[inflex]

TMPS just went off erroneously for third time. I'll take it into the dealership in next day or two and see what they have to say.

 

[ccie5754]

I wonder if inflating the tires with nitrogen would help. It's supposed to be less susceptible to temperature changes.

 

[CX-ME]

Good stuff. Regarding the SCBS, it only works between 19mph and 2mph and less than 20ft. Thats less than one and a half CX3s in front which will feel very close at 19mph!

Ive attached a detailed pdf which gives all the detail on how the system works.

Thanks for the document. I'm fairly certain I was closer than 20 feet to the vehicles in question during at least one or two of those incidents. I'll continue to note my experiences.

 

[MikiMom]

My low tire pressure monitor just went off this evening. I visually checked and everything looked fine. I don't have a tire pressure gauge (but will be getting one) and am taking the car in tomorrow to have it checked. But I'm beginning to wonder if this is going to be constant problem. The warning system in my Subaru was constantly going off. I finally just decided to ignore it and drove it that way for 5 years. Sometimes the light was on, sometimes the light was off. It was definitely weather related then but nitrogen never helped.

 

[anchorman]

Its a fairly simple system on the CX3 so until your pressures are checked, I guess we shouldn’t be too concerned.

Is there anything with your car that might effect the weight distribution? i.e. do you carry anything in the boot (trunk)?

Do you drive on unsurfaced roads that might allow one wheel to spin from time to time?