Tire flat and TPMS light NOT on?!

[gohoward]

Hello Mazdas247 community,

I have a question for anyone knowledgeable about TPMS systems, specifically whether the system has failed if the light is NOT on when the tire goes flat / or the spare is mounted?

I have a 2010 Mazda5 GT, purchased in the US but now in Belgium. Snow tires are required here, and yesterday I took it to the shop to have the regular tires swapped out for the winter ones. Everything seemed OK until, when I got home, I discovered a broken off tire pressure monitor laying inside one of the removed tires. I thought that was pretty strange, but the TPMS light had not come on when driving home.

This morning I woke up to find one of the (brand new) tires completely flat, and after taking it off could find no puncture, so I suspect the garage did a really bad job mounting the new tires. What has me puzzled, though, is that after putting on the spare and placing the flat tire in my garage, the TPMS light is STILL not on!

The light comes on at ignition and switches off as normal. Is it possible that a fuse is blown or that the garage somehow disabled the TPMS system when they broke off the sensor? Do any of you know whether the TPMS is tied to a specific fuse? I can't find anything in the owner's manual.

Thanks for your help - from Europe!

- JH

 

[Silentnoise713]

I am not too familiar with TPMS systems but would love to know how yours is disabled! Also, did you get a chance to drive it with the flat tire? I wonder if the sensor needs to detect rotational movement to turn on or only then does it send a sinal to make a read? Drive around the block with the donut and let us know.

 

[gohoward]

I didn't drive it with the flat - too much of a risk of rim damage - but I have driven a few miles on the donut. I left the flat in the garage just to make sure the sensor would not be anywhere near the receiver unit. Still no light. Again, it lights up for a second with all the other lights at ignition, but then goes out.

The paranoid side of me wonders whether the techs disabled the system after they broke off one of the sensors (I just confirmed the broken sensor I found in my old wheel is an OEM sensor for a 2010 Mazda5), but I can't imagine how they would have done it.

If anyone knows whether there is a dedicated circuit / fuse for the TPMS system, please share as I assume that is the first place to start.

 

[chief_wiggum]

after changing my summers with TPMS to my winter set without TPMS, it took about a day or ~50 miles for the car to recognize that there were no TPMS present. As far as I know, there is no dedicated circuit where you can pull a fuse to avoid the yellow TPMS light. I'm guessing that yours will come on, it just takes time (don't ask me why).

 

[gohoward]

Hmm...kind of scary if it takes the TPMS system 50 miles to figure out the sensors AREN'T EVEN ON THE CAR!

Thanks though...reassures me the system might still be working.

 

[X-Tanker]

after changing my summers with TPMS to my winter set without TPMS, it took about a day or ~50 miles for the car to recognize that there were no TPMS present. As far as I know, there is no dedicated circuit where you can pull a fuse to avoid the yellow TPMS light. I'm guessing that yours will come on, it just takes time (don't ask me why).

Same here - no TPMS in my snow tires and it took about a day for the light to come on. Now it comes on as soon as I start the car. I didn't drive anywhere near 50 miles during the time it was still off, so I don't think distance plays a factor.

 

[rat240]

yeah the tpms system in the 5 is pretty dumb when i got the car the tires had about 10 psi each and the light never turned on

 

[Davicho]

I wouldn't call it dumb. I would call it idiot proof. It most likely works like an ECM in throwing DTCs. It needs a few cycles before it triggers a light. Otherwise it probably would be throwing lights constantly and thus make consumers think that the system is faulty. Sort of like the fuel sending unit inside the fuel tank. If they designed it to move the needle inside the cluster as levels swooshed inside we never get a true reading unless we were dead stop. I am sure the light will go on the more OP drives his MZ5.

 

[Silentnoise713]

I would call it a manufacturer's effort at meeting the minimal (translate lowest cost) obligation to Fed Regulations. We can all thank Bridgestone/Firestone and Ford for this one. IMO, if it does not give you continuous and individual readings on each tire, like some higher end cars do, it is another dumb/idiot light.

http://www.nhtsa.gov/cars/rules/rulings/upgradetire/econ/TireUpgradeI.html
http://www.tpmsmadeeasy.com/whats_the_tread_act.php

 

[gohoward]

You all are on the money - the light came on today while my wife was driving the 5. She stopped just to make sure there was no flat tire. Still a bit strange it takes a day before the car realizes the sensors aren't sending any signal since they aren't even on the car.

Some good news--the shop that broke the sensors arranged with Mazda for us to get it repaired at a dealer, so hopefully this will all be behind us soon.

 

[SonicBoy]

TPMS sensors are speed dependent. If you were driving around the city (ie stop and go), good chance the light did not come on. Once you take the car up on the Highway, the system checks for sure as the sensors start sending a signal.

As other's have said it can be finicky and puzzling if things are working. Take a glance over the owner's manual and it explains a bit of how it work and what to expect.

 

[whyandrew]

after changing my summers with TPMS to my winter set without TPMS, it took about a day or ~50 miles for the car to recognize that there were no TPMS present. ...

Same here - no TPMS in my snow tires and it took about a day for the light to come on. Now it comes on as soon as I start the car. I didn't drive anywhere near 50 miles during the time it was still off, so I don't think distance plays a factor.

Sorry for digging up old threads..... reading about the TPMS

So does the TPMS ever turn off with the non-TPMS winter tires? Or you guys just live with having the TPMS light on all the times during the winter?

 

[markuszoom5]

Well I had a screw in my tire the other day. I did not know until the TPMS came on. I only lost about 4 psi but it still came on. So it seems to work on my 2010.