Tire Pressure Sensor IDs: Why, Where and When (2015)(tomorrowstechnician.com)
tomorrowstechnician.com
Tire Pressure Sensor IDs: Why, Where and When (2015)
https://www.tomorrowstechnician.com/tpms-sensor-ids-why-where-and-when/
34 comments
> I've got an RTL-SDR radio listening on 433Mhz near a public parking lot and I can definitely see the comings and goings of individual cars.
For anyone else looking to do the same with it this project is great: https://github.com/merbanan/rtl_433
For anyone else looking to do the same with it this project is great: https://github.com/merbanan/rtl_433
That's the stuff! I've got it doing MQTT into Home Assistant at my house, and CSV into a pipe to a Python script for a commercial temperature monitoring and alerting app. The commercial app is the one that happens to be near a parking lot, but I also periodically get cars showing up on Home Assistant too.
rtl_433 has been great. The ability to capture unknown-to-it signals and build decoders on the command line is really nice. I've got some cheapie driveway motion sensors that I built a decoder for. It was exceptionally easy and all the config was runtime.
rtl_433 has been great. The ability to capture unknown-to-it signals and build decoders on the command line is really nice. I've got some cheapie driveway motion sensors that I built a decoder for. It was exceptionally easy and all the config was runtime.
rtl_433 is awesome. You can even read your neighbors weather station and send that to Home Assistant using MQTT. It's worth investing in a decent antenna tuned to the ISM frequency (I use a center fed dipole, works great).
And of course there are cheap sensors you can find online for your own temperature probes.
And of course there are cheap sensors you can find online for your own temperature probes.
Hmm, now I'm curious if I could add a Home Assistant sensor to monitor my own tire pressure.
A couple years ago I picked up some Autel MX Sensors which support "cloning" through their diagnostic tool. Then I cloned my summer tire TPMS IDs to be the same TPMS IDs as my winter tires, and now I can swap them seasonally in only a few minutes with no need to make the car relearn them.
TPMS is just another surveillance method. Check your pressure like the old days.
In the old days people didn’t check them and they’d run around on underinflated tires on the highway until they had a front end blowout and took out a family minivan in the neighboring lane.
That’s why it’s a FMVSS requirement now.
There are secure TPMS implementations, e.g. ABS sensor based systems.
That’s why it’s a FMVSS requirement now.
There are secure TPMS implementations, e.g. ABS sensor based systems.
>In the old days people didn’t check them and they’d run around on underinflated tires on the highway until they had a front end blowout and took out a family minivan in the neighboring lane.
This is revisionist history through the lens of screeching people on Reddit.
Back in the old days you didn't need to "check your tires" because it's flagrantly obvious visually and in terms of handling when a tire with a 65 or 75 aspect ratio is low.
The reason we have a bunch more requirements on tires is because of all the finger pointing that ensued as a result of the Firestone Explorer debacle suddenly made formerly irrelevant few-psi differences in pressure very important. TPMS is there because you can't get a good visual read on lower profile tires until they're quit low. If you're not oblivious it won't matter you'll feel the vehicle handling funny long before they actually get low enough to cause problems though.
What "solved" blowouts was changes in construction. They started putting a couple extra belts into passenger car tires in the mid 00s. It mostly has to do with cap improvements that help prevent the sidewall from opening up at the shoulder.
Back in "the day" (so like 80s on down) everyone ran their tires to failure (usually bald, but often blowout as well) as a matter of normal practice, bought used tires left and right and blowouts were pretty common, even more common back in the really old days of tubes. It didn't reliably cause an accident unless you behaved hysterically in response, hence why everyone felt fine doing it. But that was so long ago ago, nobody much remembers it, nobody wrote about it on the internet and therefore it doesn't exist for the purposes of online discussion.
This is revisionist history through the lens of screeching people on Reddit.
Back in the old days you didn't need to "check your tires" because it's flagrantly obvious visually and in terms of handling when a tire with a 65 or 75 aspect ratio is low.
The reason we have a bunch more requirements on tires is because of all the finger pointing that ensued as a result of the Firestone Explorer debacle suddenly made formerly irrelevant few-psi differences in pressure very important. TPMS is there because you can't get a good visual read on lower profile tires until they're quit low. If you're not oblivious it won't matter you'll feel the vehicle handling funny long before they actually get low enough to cause problems though.
What "solved" blowouts was changes in construction. They started putting a couple extra belts into passenger car tires in the mid 00s. It mostly has to do with cap improvements that help prevent the sidewall from opening up at the shoulder.
Back in "the day" (so like 80s on down) everyone ran their tires to failure (usually bald, but often blowout as well) as a matter of normal practice, bought used tires left and right and blowouts were pretty common, even more common back in the really old days of tubes. It didn't reliably cause an accident unless you behaved hysterically in response, hence why everyone felt fine doing it. But that was so long ago ago, nobody much remembers it, nobody wrote about it on the internet and therefore it doesn't exist for the purposes of online discussion.
100% this. I'm happy someone else remembers too. It's really odd how in the past decade or two of mass internet adoption the world changed and it feels "dumber" in terms of all these lost experiences.
Time for me to stop internetting, enternal summer, etc.
Time for me to stop internetting, enternal summer, etc.
While you or I, or anyone else who's arguing about tire inflation on the Internet, might be the type of person who can tell just by looking at a 65 series tire whether or not it's inflated correctly -- I don't really think that's the reality of the least-common-denominator driver in the 80s or 90s. Given the number of obviously under inflated tires that I did see back in the 90s, I think it's pretty clear that many drivers either were unable to tell, or didn't bother to look.
> Back in "the day" (so like 80s on down) everyone ran their tires to failure (usually bald, but often blowout as well) as a matter of normal practice, bought used tires left and right and blowouts were pretty common, even more common back in the really old days of tubes. It didn't reliably cause an accident unless you behaved hysterically in response, hence why everyone felt fine doing it.
Yeah, tire technology wasn't great then. And yes, there were people that ran bald tires. But there are still people today that don't care about bald tires. Depends on which side of town you're on. The common way people were measuring tire tread in the 80s, if they cared, was with Lincoln's head on a penny. But also people didn't drive as aggressively as they do now, because 80s cars were slow as shit compared to what people are driving today or even in the 2000s.
> Back in "the day" (so like 80s on down) everyone ran their tires to failure (usually bald, but often blowout as well) as a matter of normal practice, bought used tires left and right and blowouts were pretty common, even more common back in the really old days of tubes. It didn't reliably cause an accident unless you behaved hysterically in response, hence why everyone felt fine doing it.
Yeah, tire technology wasn't great then. And yes, there were people that ran bald tires. But there are still people today that don't care about bald tires. Depends on which side of town you're on. The common way people were measuring tire tread in the 80s, if they cared, was with Lincoln's head on a penny. But also people didn't drive as aggressively as they do now, because 80s cars were slow as shit compared to what people are driving today or even in the 2000s.
SUVs are more dangerous than cars when tire pressure is low due a higher center of gravity and more weight (usually).
Probably why the issue came about with the Ford Explorer, a early widespread SUV
Probably why the issue came about with the Ford Explorer, a early widespread SUV
Back in the old days you didn't need to "check your tires" because it's flagrantly obvious visually and in terms of handling when a tire with a 65 or 75 aspect ratio is low.
On bias-ply tires from ‘60s, sure. You’re not going to visually check tire pressure on radials, at least not with any accuracy.
Back in "the day" (so like 80s on down) everyone ran their tires to failure (usually bald, but often blowout as well) as a matter of normal practice,
That’s just old man “kids today!” bullshit. I was an auto mechanic in the ‘80s, and the only people that did that were very poor or very stupid.
On bias-ply tires from ‘60s, sure. You’re not going to visually check tire pressure on radials, at least not with any accuracy.
Back in "the day" (so like 80s on down) everyone ran their tires to failure (usually bald, but often blowout as well) as a matter of normal practice,
That’s just old man “kids today!” bullshit. I was an auto mechanic in the ‘80s, and the only people that did that were very poor or very stupid.
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I don't consider myself oblivious, and it really scared me how little the handling changed with a flat rear tire. It also didn't make any extra noise.
I have always wondered if it is the lack of sidewall on a 225/45R17.
I did notice in time though, somehow. The tire shop also couldn't find a reason for the flat, so they simply remounted it, filled it, and sent me on my way.
I have always wondered if it is the lack of sidewall on a 225/45R17.
I did notice in time though, somehow. The tire shop also couldn't find a reason for the flat, so they simply remounted it, filled it, and sent me on my way.
> The tire shop also couldn't find a reason for the flat,
I've had a valve core get stuck open in a way that was released by poking at it. And the little plastic cap is amazingly good at holding the tire pressure in too. Sometimes rebooting the computer is the right fix.
I've had a valve core get stuck open in a way that was released by poking at it. And the little plastic cap is amazingly good at holding the tire pressure in too. Sometimes rebooting the computer is the right fix.
My VW Golf has ABS based tire pressure monitoring and for the most part it works. The disadvantage is that it can only tell you if one tire is flat. If they all get slowly flat over time there won't be a significant discrepancy between tires and they will not trigger any warning.
I consider that a worthy tradeoff though, I can just check the pressure once in a while and I get to save money on my winter wheel set.
I consider that a worthy tradeoff though, I can just check the pressure once in a while and I get to save money on my winter wheel set.
Did it have something to do with the Ford Explorer?
But anecdotally, we were driving through Chicago in the family Subaru Forester, and got a huge gash in one tire. The Soob has so much automation in its drivetrain, that it still handled OK enough and we didn't notice there was a problem until the TPMS light came on. We had to cross a couple lanes of very heavy, fast traffic, to get off the road.
But anecdotally, we were driving through Chicago in the family Subaru Forester, and got a huge gash in one tire. The Soob has so much automation in its drivetrain, that it still handled OK enough and we didn't notice there was a problem until the TPMS light came on. We had to cross a couple lanes of very heavy, fast traffic, to get off the road.
I'm surprised to not see any mention of indirect TPMS anywhere in these comments.
https://en.wikipedia.org/wiki/Tire-pressure_monitoring_syste...
It has its own shortcomings, but in my opinion they're all relatively minor and it does the job of warning the driver of potential pressure problems without wireless or in-tire sensors that require replacement.
EDIT, never mind, I wasn't seeing "indirect" in the comments but now that I look I do see "ABS", which is what iTPMS depends on for determining wheel speed.
https://en.wikipedia.org/wiki/Tire-pressure_monitoring_syste...
It has its own shortcomings, but in my opinion they're all relatively minor and it does the job of warning the driver of potential pressure problems without wireless or in-tire sensors that require replacement.
EDIT, never mind, I wasn't seeing "indirect" in the comments but now that I look I do see "ABS", which is what iTPMS depends on for determining wheel speed.
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TPMS is necessary if you have run flat tyres. Otherwise, I agree.
Tire sensor component is a wireless component, calibrated to the dash.
A compression test for whether manual transmission engine is capable of cylinder combustion.
A compression test for whether manual transmission engine is capable of cylinder combustion.
One perfect example of why cars cost so much more these days. It was totally unnecessary, too.
I've had to replace two tires (and I don't drive very much) that would've been fine if I'd have noticed them going flat. But the first thing I noticed was the thumping and at that point they were badly damaged from driving them under inflated already.
There's a third incident like that too, but since I figured out that it had been flat when I started out, that I could've prevented it by looking at the tires (with a flashlight, cause it was dark).
There's a third incident like that too, but since I figured out that it had been flat when I started out, that I could've prevented it by looking at the tires (with a flashlight, cause it was dark).
I find it useful, especially after hitting a bump and getting a punch flat.
In the old days, you had to drive a couple miles to be certain you really had a flat, at which case things were damaged.
In the old days, you had to drive a couple miles to be certain you really had a flat, at which case things were damaged.
Yeah, TPMS and the way its implemented is a BAD idea.
1. Data is not signed.
So data can be easily spoofed and jam up the real sensor's transmissions.
2. Serial number is not obfuscated or in a reduced serial number set.
This allows TPMS trackers to be placed at high vehicle through areas and uniquely track cars. Is dying out due to Flock and ALPRs.
3. Some cars, primarily luxury, will force slow you down to 15mph, honk horns, and go into limp mode.
Note this is trusting unencrypted, unsigned, cleartext data. This is a terrible idea, and you cant turn it off.
1. Data is not signed.
So data can be easily spoofed and jam up the real sensor's transmissions.
2. Serial number is not obfuscated or in a reduced serial number set.
This allows TPMS trackers to be placed at high vehicle through areas and uniquely track cars. Is dying out due to Flock and ALPRs.
3. Some cars, primarily luxury, will force slow you down to 15mph, honk horns, and go into limp mode.
Note this is trusting unencrypted, unsigned, cleartext data. This is a terrible idea, and you cant turn it off.
> 3. Some cars, primarily luxury, will force slow you down to 15mph, honk horns, and go into limp mode.
I'm surprised some company hasn't sold a "gun" to law enforcement that will disable cars remotely this way.
I'm surprised some company hasn't sold a "gun" to law enforcement that will disable cars remotely this way.
TPMS data is "questionable" enough already that no OEM is using it's sudden disappearance as a key do to anything drastic.
I can see them doing it if the data goes from good to bad and then the bad persists over a key off cycle though.
I can see them doing it if the data goes from good to bad and then the bad persists over a key off cycle though.
Its not disappearance.
Look at what happens if you spoof and spam a 0kPa event on various cars.
Some show a tpms warning. Some luxury ones do limp mode.
Look at what happens if you spoof and spam a 0kPa event on various cars.
Some show a tpms warning. Some luxury ones do limp mode.
This is no different than the internet, really. "Hey, we made this thing to operate in a safe environment." Years later: "Oh, crap, what do you mean it needs to be secured?"
> 3. Some cars, primarily luxury, will force slow you down to 15mph, honk horns, and go into limp mode.
Source? I can't find any reference. It looks like you're hallucinating.
Source? I can't find any reference. It looks like you're hallucinating.
Ah, the new AI insult.
Nah, I'm not providing exploit code to something unpatchable.
But if you use a rtlsdr, read, decode, modify, and then use a Hackrf to generate the waveform... Yeah, it works.
No ai. No hallucination. Just good at signals.
Nah, I'm not providing exploit code to something unpatchable.
But if you use a rtlsdr, read, decode, modify, and then use a Hackrf to generate the waveform... Yeah, it works.
No ai. No hallucination. Just good at signals.
A link to any article/manual/reference about this vehicle response to low tire pressure would be enough... if it exists, surely the manufacturers would have documented it.
https://www.reddit.com/r/wrx_vb/comments/1g8dubh/fyi_no_tpms...
I'm unsure of all the different cars. Its all how a blowout report is handled by the ECU.
I know my cars, Toyotas Prius 2013 and rav4 2017 only do the light. No limp mode.
Ive tested it on a friends Benz, and that one gets positively rude. Limp mode, cabin buzzer, console blinking lights.
I'm unsure of all the different cars. Its all how a blowout report is handled by the ECU.
I know my cars, Toyotas Prius 2013 and rav4 2017 only do the light. No limp mode.
Ive tested it on a friends Benz, and that one gets positively rude. Limp mode, cabin buzzer, console blinking lights.
Aside: I'll never get another chance to share this, so please forgive the "humor".
Once my wife was driving, with me as her passenger when, the car's TPMS indicator came on. She was concerned and said "There's this 'TPMS' warning light here. What does that mean?".
Without even thinking I said "That probably means something." Likely the greatest accidental fitting of words to an initialism I've ever made in my life.