littlescrote
Posts: 301
Joined: Fri Jul 26, 2019 3:52 am

Re: TPMS on the PHEV - no pressures, what a joke!

Mon Nov 11, 2019 3:55 am

Do we know that the wheel sensors actually measure and transmit pressure, or are they just a binary switch that is either above a pressure or below it?

Regulo
Posts: 766
Joined: Tue Sep 02, 2014 4:01 pm
Location: Essex, England

Re: TPMS on the PHEV - no pressures, what a joke!

Mon Nov 11, 2019 4:05 am

The fact that you can re-calibrate the trigger point for a warning suggests they're not a simple on-off switch, but transmit real-time variable readings.
Regards, Ray. 2014 GX4H Glacier blue.

It's the 21st century - so where's my nuclear-powered flying car, then?

STS134
Posts: 309
Joined: Wed Jul 11, 2018 4:35 pm
Location: Saratoga, CA

Re: TPMS on the PHEV - no pressures, what a joke!

Mon Nov 11, 2019 10:25 am

littlescrote wrote:Do we know that the wheel sensors actually measure and transmit pressure, or are they just a binary switch that is either above a pressure or below it?
The sensors actually measure pressure. And the transmitters transmit pressure (as well as temperature). The system uses FSK modulation and 100 kHz bandwidth to transmit its data at either 315 MHz or 433 MHz. http://i56578-swl.blogspot.com/2017/08/ ... -tpms.html

This guy created a software-defined radio that can see both values:
https://www.youtube.com/watch?v=bKqiq2Y43Wg

littlescrote
Posts: 301
Joined: Fri Jul 26, 2019 3:52 am

Re: TPMS on the PHEV - no pressures, what a joke!

Tue Nov 12, 2019 8:54 am

STS134 wrote:The sensors actually measure pressure. And the transmitters transmit pressure (as well as temperature). The system uses FSK modulation and 100 kHz bandwidth to transmit its data at either 315 MHz or 433 MHz. http://i56578-swl.blogspot.com/2017/08/ ... -tpms.html

This guy created a software-defined radio that can see both values:
https://www.youtube.com/watch?v=bKqiq2Y43Wg
Interesting but not PHEV specific is it? You are assuming (probably correctly given that there are very few different standards for these things) that the OEM sensors do the same.
Regulo wrote:The fact that you can re-calibrate the trigger point for a warning suggests they're not a simple on-off switch, but transmit real-time variable readings.
Can you? Where? Or is that dealer (or ETACS) only?

Regulo
Posts: 766
Joined: Tue Sep 02, 2014 4:01 pm
Location: Essex, England

Re: TPMS on the PHEV - no pressures, what a joke!

Tue Nov 12, 2019 10:15 am

Lifted from a previous post on here:

Reset of low tyre pressure
warning threshold

The threshold is set based on the tyre pressure which the reset function is executed by following procedure.

1. Operate the multi-information display switch to switch the information screen to the menu screen.
2. Lightly press the multi-information display switch to select “ ” (reset of low tyre pressure warning threshold).
3. Hold down the multi-information display switch for about 3 seconds or more, the buzzer sounds.
4. The warning lamp start flashing slowly.
5. Drive for a while. The reset is completed if the warning lamp goes out.


I presume (it's not clear from the text), that this will reset the threshold as a set amount below whatever the pressure in the tyres is when this reset procedure is done. If that makes any sense? So the sensors must be transmitting a value that the software interprets as a "starting point" for the warning function. You can't actually set a value of pressure, just a base point, from which the software calculates pressure drop. I've never fiddled with this, so I can't say whether this is actually how it works or not.
Regards, Ray. 2014 GX4H Glacier blue.

It's the 21st century - so where's my nuclear-powered flying car, then?

littlescrote
Posts: 301
Joined: Fri Jul 26, 2019 3:52 am

Re: TPMS on the PHEV - no pressures, what a joke!

Wed Nov 13, 2019 4:22 am

That makes sense, if you can do that then they must be transmitting pressure.

oscarmax
Posts: 138
Joined: Sat Oct 27, 2018 3:47 am

Re: TPMS on the PHEV - no pressures, what a joke!

Wed Nov 24, 2021 3:17 am

I regularly check and amend my tyre pressure, however due to commitments I have not check the pressure since the end of September. Front tyre down to 28 psi rear down to 33psi (Rear tyre pressure normally set to 38 psi due to carrying a heavy Motability scooter), I don't have the confidence or ability to mess with the tyre menu settings so I brought one of these, I have an older version on our caravan for the last 6 years it simple/ easy and extremely accurate.

I decide to buy one off these £98.00 including my discount, easy to set up just fit the sensors in place of the tyre valve cap and the system does the rest, I now can monitor both the tyre pressure and temperatures.

https://www.tyrepal.co.uk/product/kit-b ... so-sensors
Mitsubishi Outlander 2.4 PHEV Design 2020 Towing a Swift Conqueror 480 2016 1500kg

Please be patient I suffered a brain injury several years ago and get confused at times

jaapv
Posts: 4662
Joined: Mon Dec 16, 2013 1:18 pm
Location: Netherlands

Re: TPMS on the PHEV - no pressures, what a joke!

Wed Nov 24, 2021 8:59 am

I have the Steelmate system for that.
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littlescrote
Posts: 301
Joined: Fri Jul 26, 2019 3:52 am

Re: TPMS on the PHEV - no pressures, what a joke!

Thu Nov 25, 2021 3:56 am

Claiming to be able to measure any meaningful temperature at the valve cap is a joke.

AndyInOz
Posts: 619
Joined: Wed Sep 09, 2015 5:05 pm
Location: Australia

Re: TPMS on the PHEV - no pressures, what a joke!

Thu Nov 25, 2021 1:14 pm

I fitted internal tyre pressure and temperature sensors to mine.

(A little solar powered unit on the dashboard gives a constant display of temperature and pressure for each tyre while the car is in motion, or if you press a button on the side of the dashboard unit.)

I had the steelmate valve top type for a while and found them to be excellent, they gave me early warning of a slow leak which meant that the tyre could be repaired before the tek screw had done too much damage.

I only replaced them because I was sick of removing them every time I wanted to put air in the tyres.
2014 PHEV Aspire, Arctic Silver;
Black Interior;
Hayman Reese removable tow bar;
1.5kW Solar, grid connected.

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