Automotive TPMS - DIY?

[glarsson]

I was a TPMS developer for 5 years (2006-2011):

Perhaps you can answer a question I have been unable to get an answer to. The TPMS system used by Saab (RIP) (and most likely other GM brands) used different TMPS systems for the US market vs. the rest of the world. The main hardware difference (as described in the workshop manual) was that the sensors used for the US market only reported pressure and the sensors for all other markets reported both pressure and temperature. Do you know the reason for this difference?

[Zucca]

Do you know the reason for this difference?

All the sensors I know read out temperature and pressure and send them to the car. What then the car will report depends not by the sensor but is a HIM development choice. Normally there was no need to tell the T, just the P. The car knows everything, it just tells you what develpmpent/law think you need.
 
Maybe the old Saab sensor needed to send just the pressure and the temperature was not necessary back in those days. I can imagine in the first TMPS systems the T was not a concern, so the sensor hat only the P and no T on the radio to save battery energy.

[IanMacdonald]

Isn't so great  in the EU, where if it goes wrong it's an MoT failure. So we now have a situation where all non-mandatory safety features are a potential liability that can put your car off the road.

[CJay]

Isn't so great  in the EU, where if it goes wrong it's an MoT failure. So we now have a situation where all non-mandatory safety features are a potential liability that can put your car off the road.

Except they are a mandatory safety feature on new vehicles and have been for some years along with ABS so it's a reasonable thing to fail a vehicle for if safety features that are fitted aren't working.

 I don't think it's unreasonable to expect a vehicle to be up to specification and be safe on the road so I don't see quite what the problem is?

[paulca]

I don't think it's unreasonable to expect a vehicle to be up to specification and be safe on the road so I don't see quite what the problem is?

The extra cost when you replace tyres or change wheels twice a year.  Plus the side issue of tracking people via the sensors etc.

I'm okay, my car is less than a year old, won't need an MOT for another 3 years and even then it will be summer time, so the wheels with the sensors will be on the car then.

[CJay]

I don't think it's unreasonable to expect a vehicle to be up to specification and be safe on the road so I don't see quite what the problem is?

The extra cost when you replace tyres or change wheels twice a year.  Plus the side issue of tracking people via the sensors etc.

I'm okay, my car is less than a year old, won't need an MOT for another 3 years and even then it will be summer time, so the wheels with the sensors will be on the car then.

Wasn't to you, was commenting on Ian McD's post about MOT failures for what he incorrectly claimed were optional safety features, I still don't believe it's unreasonable to expect mandatory safety equipment to work and for the car to fail an MOT if it doesn't.

It's pretty easy to buy sensors and have them programmed with a copy of the ID from your original ones if you wish to avoid having to pay Toyota to reprogram the ECU every time as well, they're about £50 each which doesn't seem excessive if you have the money to run a new(ish) car and have a spare set of rims and tyres stored in a shed somewhere.

The other advantage of that is that you have a copy of your data so as and when the TPMS gets damaged by an ape of a tyre fitter you don't need an ECU reprogram, just a clone of the spare sensor in your 'winter' wheels.

As for tracking, I'm absolutely not an advocate of the surveillance state but even so, I'd really not worry about black helicopters monitoring your TPMS to track you, it's far easier to track your mobile, the Bluetooth in the car, or, shock horror, the whopping great big registration plates on the front and back of it with the hundreds of thousands of CCTV and traffic cameras you can drive past.

[paulca]

It's pretty easy to buy sensors and have them programmed with a copy of the ID from your original ones if you wish to avoid having to pay Toyota to reprogram the ECU every time as well, they're about £50 each which doesn't seem excessive if you have the money to run a new(ish) car and have a spare set of rims and tyres stored in a shed somewhere.

True, but my winter rims were only 59.99 each, so it's a sizable expense relatively.