Tech Q&A: Talking TPMS

Cary Hubbard
by Cary Hubbard
tech q a talking tpms

Greetings Readers,


Let me start by saying thank you for the kind words I received and for welcoming me aboard! I am looking forward to this first response and all the others that I know will follow.


For my first Q&A piece, I received an email from Ron asking about TPMS's, aka “Tire Pressure Monitoring Systems.”


Thank you for sending in your email Ron.


Send your questions to this carysgarage@gmail.com, and we'll do our best to answer them.


Hi, Cary (and welcome aboard),


Quick question: why don't they make it possible to replace the battery

in a TPS sensor instead of replacing the whole thing? I think I know

the answer to this one, but you just may surprise me.


I recently had one die and the shop I go to (which usually treats me

quite well) is asking $90+ for just the sensor. That's roughly $20

more than Rock Auto's price on the OEM. Schrader has got them (again

at Rock Auto) for $22. Which reminds me of a second question.


The listings for these at Rock Auto say they are 'programmed for exact

year/make & model' and just need to go through the OEM relearning

procedure. My mechanic said they all have to be programmed. Which is

accurate?


Thanks for any 'enlightenment' you can offer.


Ron


Ron,


Let me start off by explaining that in the United States car market the Tire Pressure Monitor was required on all vehicles from September 2007 according to the “TREAD” act as a form of safety equipment on passenger vehicles.


According to the writers of this safety act, driving on a deflated tire(s) is unsafe and could cause any sort of accident, so they mandated a way to quickly be informed of a low tire situation.


Now I am sure there is a way to make the in-tire sensors have the ability to have changeable batteries, and I have seen people make videos about how to do such a process. But the plain and simple is that the sensor itself is considered a piece of safety equipment and the life of the battery is also the life of the unit itself, and because it is part of a safety system and the sensor is a wear item, they want to make sure that it works to the best of its ability.

Depending on the size of your tire the sensor can make upwards of over 6-8 million (on average) revolutions per 10k miles, and since we know the national average is 12-15k miles a year, and the life range of a sensor is expected to be anywhere between 5-12 years with an average of 7 years, you can see how that the sensor in the wheel can see a lot of movement and transmissions to the computer system.


There might be some sort of reason behind manufacturing and making money when it comes to the sensors having a sealed battery, but it’s hard to truly say and I really only know the technical aspect of the whole picture and how the system works.


As far as price and programming go, I can’t speak to the shop that is selling the parts as they are depending on their own supply source and mark-up that they decide on. Most times you will always be able to find it far cheaper online since you are taking the “middle man” aka the shop out of the picture.


By them saying “Programmed for the Exact year/model” that mainly refers to the fact that it will be able to communicate with that specific vehicle's TPMS frequency receiver, but all TPS need to be programmed to the vehicle so the computer can communicate to the unique ID of the sensor being installed and the vehicle can communicate the data to the display screen or however it indicates the tire pressure warning.


There are older vehicles that were produced with a form of TPMS that worked a bit differently than they do today, those vehicles were made far before the system was required and the operating procedures for them very well might function a bit differently. So all of the info stated above is for the modern systems that we have in vehicles today.


Thank you for the email Ron asking your question!


I look forward to more questions from all of you out there!


[Image: Tetrisme/Shutterstock.com]


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  • Kcflyer Kcflyer 7 days ago

    My 2015 Fit had no in tire sensors. Just measured wheel speed somehow to detect low pressure. Simple, cheap, effective. So of course those systems are rare.

    • Bobbysirhan Bobbysirhan 7 days ago

      They use the same wheel speed sensors needed for the ABS and stability control that cars have had for years, so there really is no reason for the fiddly TPMS sensors in cars that are meant to last longer than seven years. I suppose they're fine for disposable 'luxury' cars, which display the tire pressures on the dashboard to dazzle their lessees.


  • Kcflyer Kcflyer 6 days ago

    Exactly, complexity for complexity sake.

  • MichaelBug For me, two issues in particular:1. It can be difficult for me to maintain my lane on a rainy night. Here in southeastern PA, PennDOT's lane markings aren't very reflective. They can be almost impossible to make out when wet.2. Backing out of a parking space in a lot with heavy pedestrian traffic. Oftentimes people will walk right into my blind spot even if I am creeping back with my 4-way flashers blinking. (No backup camera in my '11 Toyota Camry.)Michael B 🙂
  • Tagbert When you publish series like this, could you include links to the previous articles in the series so that we can follow through? Thank you. Edit: now I see a link embedded in the first paragraph that goes to the previous story. It wasn’t clear at first where that link went but now I understand.
  • DungBeetle62 When you're in one of these, you life in a state of constant low-level nervous about 90% of the time. But that other 10% kinda makes up for it.
  • Garrett Instead of foisting this problem on the car companies and the people who buy cars, make those who possess liquor licenses and those who purchase alcohol take on the economic cost of this problem.
  • Inside Looking Out Thieves are gradually winning the war with law enforcement in America not only in California and that is the tragic fact. They would rather put in jail police officer than thief.
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