[HN Gopher] Tire Pressure Sensor IDs: Why, Where and When (2015)
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       Tire Pressure Sensor IDs: Why, Where and When (2015)
        
       Author : walterbell
       Score  : 23 points
       Date   : 2025-10-06 11:28 UTC (2 days ago)
        
 (HTM) web link (www.tomorrowstechnician.com)
 (TXT) w3m dump (www.tomorrowstechnician.com)
        
       | jsharkey wrote:
       | 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.
        
       | mystraline wrote:
       | 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.
        
         | xnx wrote:
         | > 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.
        
           | potato3732842 wrote:
           | 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.
        
             | mystraline wrote:
             | 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.
        
         | psunavy03 wrote:
         | 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?"
        
         | henvic wrote:
         | > 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.
        
       | hackernewsdhsu wrote:
       | TPMS is just another surveillance method. Check your pressure
       | like the old days.
        
         | kube-system wrote:
         | 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.
        
       | EvanAnderson wrote:
       | 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. While I'm sure ALPRs are taking over any TPMS-
       | based surveillance there's definitely a risk there.
       | 
       | 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.
        
         | joecool1029 wrote:
         | > 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
        
           | EvanAnderson wrote:
           | 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.
        
             | Thrymr wrote:
             | Hmm, now I'm curious if I could add a Home Assistant sensor
             | to monitor my own tire pressure.
        
       | lisbbb wrote:
       | One perfect example of why cars cost so much more these days. It
       | was totally unnecessary, too.
        
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