TPMS

It does have some reprogramming capability dependent on the car. For my range rover it seems to have a comprehensive set of programming/re-programming capability. For the Suzuki it can do some ECU and BCU programming including immobilisers and key reprogramming. For Suzuki TPMS it can programme the sensor locations manually so you do not have to wait for the "learn" function to kick in.

As for the Iron Gates I still support my original theory. The Iron Gates unit (at least the one I have) has a large arrow on it stating "to the front" - this means it needs alignment with the vehicle long axis. This means that if it has its own accelerometer in it then it will know if the car is turning left or right.  Therefore if it knows its turning it then can send fake accelerometer values to the tpms controller to say that the inside wheels of the turn are slowing and the outside are speeding up. Equally it can send the fake accelerometer readings for front and rear wheels.Imagine turning left:

• Front-right wheel (outer) → fastest
• Rear-right wheel (outer) → slightly slower than front-right
• Front-left wheel (inner) → slower
• Rear-left wheel (inner) → slowest

So if it detects the car turning left it sends fake accelerometer readings to show the wheel differences as example above and the TPMS controller then thinks it knows which corner the sensors are on.

I agree with you on the fact that suzuki have a faster learning sequence and a slower standard state sequence and this does add doubt into the workings but it only needs the angular data at the start to confirm the wheel positions because once you are up to speed the wheels are not going to change corners so I think all the work is done in the first 10 minutes or so.
 

The scan tool sounds extremely useful, particularly for something at that price point. When I was still doing this stuff, I paid far more (another zero) for something with similar capability and a far worse graphical interface.

The sensors have clearly advanced in tech since then too, I'm fascinated that the accelerometers are indeed such, providing such granular data -- though I'm still puzzled at how gappy "snapshots" are turned into a data stream that can be usefully compared with the ABS wheel sensor data. And also how this could be done in the relatively dumb TPMS module -- or perhaps the module is dumping everything on the bus and letting the ECU/BCU do the heavy maths. That would be a big difference from what I described.

The Iron Gate thing also still eludes me a bit. I see your point about having an accelerometer, and that aligns with the maker's instructions about ensuring the unit is strapped down. But why would it be important to put the unit in a specific place (I think with the expectation that it is near the TPMS antenna)? And why would the unit need to be recalibrated if it were placed at a higher position on the body?  And how would the unit know how to parse data from the TPMS sensors actually mounted on the car, when it is interpolating 1 to 3 missing positions?

I don't think the Iron Gate unit is going to be able to convincingly fake wheel speed data based on an internal accelerometer reading direction-- or the instructions would just say "install and go," no fuss with programming. But there may be a way that the designer worked around that and still used accelerometer placeholders-- perhaps by having the unit dump guesses stepwise until it is likely to hit values the TPMS module will accept?

But I've learned a lot from the data you posted. Clearly my automotive experience is getting dated -- I am starting to feel like those fellows from my youth who thought in terms of carburettors and thought fuel injection was hocus-pocus. Thanks again.



Edit: I'm still very curious how the OP got his Jimny to read the sensors at stop, without driving or manually activating each wheel.  But probably few would have the patience to read this thread to the end just to answer that question...

My Iron Gates unit doesn’t have an arrow, just mount it with the label facing upwards.

My guess would be that TPMS is a two stage thing:

Stage 1 the TPMS has to see four sensors, that keeps it basically happy, I.e. not showing any errors.

Stage 2 the TPMS then works out which wheel is which.

If all of the pressures are good then no one worries and it gives the controller as long as it wants to work out which is which.

If you have a flat or very low pressure, it will be able to work that out pretty quickly.

So I suspect with the Iron Gates unit, the TPMS never fully works out which is which or at least it isn’t very consistent or accurate, but then the TPMS module doesn’t care, all pressures are good.

My observation of live data from szviewer on the gen3 is that first the controller remembers the last live data it saw and presents it when asked with the car off or not moving. It then populates the acceleration first closely after is pressure. Temperature and location then turn up but location especially seems to be at least in part a stored field. I know this as I had issues with my cheap sensors leading to one being replaced with a programmable one that has a very different identifier. I have subsequently moved this wheel diagonally to the back but the system still thinks it is on the front after nearly 7k miles.

Motacilla wrote:

Edit: I'm still very curious how the OP got his Jimny to read the sensors at stop, without driving or manually activating each wheel.  But probably few would have the patience to read this thread to the end just to answer that question...

I don't know if this helps any...

 

It's from the FSM for the JB74, there is a fairly comprehensive write up on what there is & how it works, than I haven't really gone through, partly because we don't get TPMS on our Jimnys.