Low tyre pressure warning

[stani]

So today, while driving all day, the "low tire pressure warning" also came on.
Pressure drop in half a year approx. 0.2 - 0.3 bar.
The tire pressure values ​​are on the sticker on the driver's door pillar.
I have it written there for the front tires 2.4 and for the rear tires 2.3 BAR.
I use Michelin CROSSCLIMATE 2 XL 185/60 R15 all-season tires.
After inflating with this device (I used it for the first time and was very satisfied), then calibration in the Jazz's main display menu - a simple matter. 

[stani]

What happened today: I'm driving a short distance to the supermarket, and I think I can hear something faintly behind me.
I heard something similar last week, but I didn't pay attention to it. I thought it was probably an icicle or mud.
The car hadn't driven anywhere all week until today.

Well, I arrive at the supermarket parking lot, I stop, and immediately one person says to me: "Sir, you have a flat tire"...Oh yeah, really. I also have a battery compressor in my car, so I inflated the tire. I come back from the supermarket and the tires are holding up, so probably not a big hole. 
I drove to my favorite tire shop and the problem was solved in 15 minutes. It was a small screw, they said.

But the question and especially the problem is: how come the system didn't report a drop in pressure, not even a flat tire?!?

Some time ago (see my previous post), I inflated the tires and calibrated the system. There's nothing you can do wrong there, right? There's only the "Initialize" option, nothing more.
So where did the mistake happen?... Does anyone know?...

[ColinB]

The handbook for the Mk3 says:
 "The system does not monitor the tyres when driving
at low speed"
I suspect it's the same for the MK4, you might want to check.

It's not clear what Honda means by "low speed", but if your journey was a short urban one it's possible the system wasn't triggered.

Personally I make a point of looking at the tyres before driving off.

[stani]

ColinB: Yes, you're right, for the Mk4 the same, it's written that way in the manual. I was definitely going 50 km/h - is that a low speed?
It was dark in the morning, I didn't notice it. Not even last week, I went either early in the morning or in the evening.
It was probably a small hole, the tire was probably leaking slowly.

Edit by Admin: removed reference to deleted post

[ColinB]

I was definitely going 50 km/h - is that a low speed?

I think you've just proved that, in the eyes of the Deflation Warning System, 50kph is indeed a low speed!

Actually, it makes sense that a system that relies on differential wheel speeds will be ineffective at low vehicle speeds. If the rotational speeds are low, then any difference between wheels in the event of deflation will be small and probably insufficient to trigger the warning. The perils of relying on the technology without being aware of the limitations of that technology!

[Downsizer]

As the alarm works by comparing rotational information with the reference data from initialising, it will inevitably take quite a lot of rotations to activate it. The handbook p392 says about half an hour at speeds of 40-100 kph are needed to calibrate, so presumably something similar is needed to trigger the alarm.

[stani]

Well, I'm looking at it in the manual, but it's a bit unclear. Does it mean that when I initiate calibration I have to drive somewhere for at least 30 minutes at a speed of 40 to 100 km/h continuously for the calibration to complete?

[Downsizer]

Yes, that’s right. The first step is initialisation, followed by calibration on the move, which does not have to be immediately after, or all in one trip.

[Lord Voltermore]

I think the wheel rotation sensing system is smart enough to  allow for the  fact that the outer wheels will inevitably rotate over a longer distance   than the inner wheels when turning corners  or travelling round bends.   Sharp turns may even use steering angle sensors  to compensate for this  but more gentle bends may  still alter rotation speeds with no measurable change in steering angle.    Therefore the recalibration relearning procedure  needs to be long enough, straight enough and fast enough to relearn a new normal average tyre rotation.      I suspect if you reset the system    but then only drive short distances in town, with maybe lots of turns  the system may be unable to establish a satisfactory calibration . Until it does it would be unable  to detect a discrepancy due to tyre pressure loss. 

I dont know for sure but suspect that had you been able  to continue driving in town for a few more  kilometers  the TPMS  would have concluded that the  current calibration cycle was too inconsistent and failed. It might then reactivate the TPMS warning so you would reset the system and try again . Even if the tyres are in fact OK.  It was perhaps just your bad luck you really had a puncture .

If I am right about this its perhaps a warning to others  not to assume the activation was a false alarm because the tyres look ok.   Not only should you keep an eye on them until sure everything is ok,  but indeed periodically check tyre pressures and condition anyway ,  not rely entirely on getting a warning from a TPMS.  Many of us are guilty of this. 

[Lincolnshire Rambler]

When i got my puncture the AA put their universal space saver wheel on to allow me to drive behind the AA van to the tyre garage 4 miles away . The Jazz tyre warning symbol pinged once doing 20mph on the road departing the car park . To me thats a low speed warning ?

[stani]

Well, maybe active TPMS might be better in these cases, even though it is more complex and expensive.

[JB]

Vauxhall insignia I owned before Jazz used to show all four wheels with pressure
and would flash on and off if any tyre was under or over inflated would flash at the
side of the offending tyre.

[Hicardo]

Mine change with the seasons. At least 4 or 5 psi

Ditto. Ive had the TPMS activate on the previous ~Crosstar, and both rears i think were down to 31psi.  As there was no obvious other issue, i re-inflated, and all was fine. Assumption would therefore be theres a lower limit that will trigger the warning, rather than only a pressure diff to the others that triggers it

[stani]

Assumption would therefore be theres a lower limit that will trigger the warning, rather than only a pressure diff to the others that triggers it

Well, that just didn't happen to me. 

[John Ratsey]

I think there's a minimum distance at the start of each journey for the TPMS to be sure that there's a soft tyre rather than different relative wheel speeds caused by turning losts of corners. I recall reading somewhere that someone drove off with flat tyre and it was wrecked by the time TPMS raised the alarm. I suspect that Honda's algorithm could be improved so that the worse the problem then the quicker it is to raise the alarm.