Tyre deflation false alarms

[Peter5145]

I have a Mk 3 which is approaching five years old, and recently I've been getting a lot of false alarms or overzealous warnings from the tyre deflation indicator.

Very often it seems that as soon as I build up some speed on the motorway and the air in the tyres warms up, it triggers the indicator. I carry a pressure gauge and a pump, so it's usually no more than a minor inconvenience. Generally I find all four tyres are properly inflated anyway.

As I recently had a genuine puncture leading to full deflation of the tyre, I can't just ignore it and have to stop and check when convenient, but surely it's being very over-sensitive.

[dayjavoo]

When this first happened to me, just two weeks after taking delivery of my Jazz, I immediately pulled over and checked the tyres and discovered that there was no sign of loss of pressure in any of the tyres.  It's happened a few times since then but if the car feels OK I've felt confident enough to drive carefully to the next convenient services.  I thought the false alarms could be due to the tyres warming up and the pressures increasing but the handbook says "The low tyre pressure indicator will not come on as a result of over inflation."  I just recalibrate the system and the warning goes away - until the next time!  I also recalibrate after any routine check and adjustment of tyre pressures.

[Kremmen]

How did you initialise the system ?

The original advice in my old Civic manual was to drive at least 15 miles after firing off the calibration, taking in all manner of bends and speeds so it can learn the expected rotational values

If you don't do the 15 miles then it can't calibrate hot tyres

[ColinB]

Most of the reports about TPMS false alarms seem to involve high speeds (motorways or fast dual carriageways). I wonder how many people actually reach those speeds when recalibrating? May be difficult if there’s no convenient fast road nearby. If not, then the system seems unlikely to have “learnt” the necessary parameters.

[Lord Voltermore]

I still think the Honda indirect TPMS system has its advantages.   With a direct system the pressure sensor transmitters in the tyre may need to be replaced or serviced if their battery runs low. In which case its sensible to get all 4 done.   Also a faulty sensor  would be a malfunction that would fail the MOT.  Here is a paste from the official MOT testers manual 

Tyre pressure monitoring system (TPMS)
The inspection of the tyre pressure monitoring system (TPMS) is for M1 vehicles first used on or after 1 January 2012.

The TPMS warning lamp (see diagram 3) will generally illuminate and go off again when the ignition is switched on. If the system has identified a previous pressure loss, the lamp will remain illuminated. This does not automatically mean the system has a malfunction. In the event of a system malfunction, the lamp may flash a number of times and then remain on.

Warning messages on dashboard displays are not a defect in their own right, but may assist the tester in determining that the warning lamp is illuminated because a malfunction exists.

If it is unclear the warning lamp is indicating a system malfunction and not a simply indicating that one or more tyre pressures are low, then advisory information should be added to the test result.
     
If the Honda system gives a false alarm it is technically still working as a warning device, albeit over sensitive .

 A  false alarm is a nuisance, but its only a matter of stopping, checking the tyres are ok, and then resetting the system.  Even if you have TPMS you should still check the condition and pressure of your tyres  regularly ,although you might not chose to do it  on a rainy night in a layby.     

[Peter5145]

When this first happened to me, just two weeks after taking delivery of my Jazz, I immediately pulled over and checked the tyres and discovered that there was no sign of loss of pressure in any of the tyres.  It's happened a few times since then but if the car feels OK I've felt confident enough to drive carefully to the next convenient services.  I thought the false alarms could be due to the tyres warming up and the pressures increasing but the handbook says "The low tyre pressure indicator will not come on as a result of over inflation."  I just recalibrate the system and the warning goes away - until the next time!  I also recalibrate after any routine check and adjustment of tyre pressures.

Good to know I'm not the only one!

I do as you say, but it's inconvenient having to stop and check the pressures on what seems like every other longish journey I make.

I can't just assume it's a false alarm, as I did have a genuine alert where there was a puncture and fairly rapid deflation. On this occasion I ended up driving about six miles before stopping to check. Perhaps with hindsight I should have stopped sooner, but obviously if you're on a motorway without hard shoulders that's impossible.

I might try the suggestion of resetting after a fast run to see if that makes any difference.

[ColinB]

I might try the suggestion of resetting after a fast run to see if that makes any difference.

Not sure that's what the calibration process requires. It asks you to cover the distance at a range of speeds and making turns in both directions during the calibration.

[Peter5145]

Not sure that's what the calibration process requires. It asks you to cover the distance at a range of speeds and making turns in both directions during the calibration.

I was under the impression that you just reset it at a particular point in time. Are you saying you somehow have to start calibration and then stop it?

[ColinB]

Not sure that's what the calibration process requires. It asks you to cover the distance at a range of speeds and making turns in both directions during the calibration.

I was under the impression that you just reset it at a particular point in time. Are you saying you somehow have to start calibration and then stop it?

You certainly have to start the calibration process manually, but it stops automatically. It's all in the Handbook around pages 443-444 (page numbers may vary with Handbook version).
"The calibration process requires approximately 30
minutes of cumulative driving at speeds between
40–100 km/h (25–62 mph).
"

[Peter5145]

You certainly have to start the calibration process manually, but it stops automatically. It's all in the Handbook around pages 443-444 (page numbers may vary with Handbook version).
"The calibration process requires approximately 30 minutes of cumulative driving at speeds between 40–100 km/h (25–62 mph)."

Thanks, I didn't realise that. As they say, always RTFM. Maybe that's why the light has a tendency to come on after driving on the motorway for 10-15 minutes.

Anyway, later today I'm making a trip of about 30 miles along mixed roads, so I'll initialise it before I start and see if that makes a difference.

[TnTkr]

My Jazz sometimes throws the alarm after some highway speed driving. But I have been able to locate the reason to be very slightly jamming rear brake caliper. It makes that wheel a bit warmer and thus increases the tyre pressure. After getting the brake calipers cleaned, the false alarms don't appear anymore until after next winter.

[peteo48]

When I had my Mk3 the false alarms drove me mad and, as others have said, they were triggered by Motorway driving. I did repeated recalibrations and, eventually, they went away.

I still feel the system is unfit for purpose. False alarms result in a lack of trust in the system so, when a genuine one comes along, you are tempted to ignore it.

The Mk4 does seem better in this regard.

[TnTkr]

I'm such an old school motorist, that I feel the flat tyre. I don't want or care about usually false warnings.

[dayjavoo]

I'm such an old school motorist, that I feel the flat tyre. I don't want or care about usually false warnings.

That's what I think, an experienced driver will usually 'feel' a deflating tyre.  However these TPMS aren't just optional extras but mandatory requirements on new cars since 2012 in the UK.  So they should work properly and presumably the car would fail its MOT if they don't.  I understand that the indirect TPMS work by sensing the increased revolutions that a deflating tyre would make as its radius decreases.  I don't quite see how warm tyres and presumably higher pressures from high speed driving could trigger a false alarm?

[ColinB]

... I don't quite see how warm tyres and presumably higher pressures from high speed driving could trigger a false alarm?

It shouldn't. It's a deflation warning system, and the Handbook, page 443 says:
"The low tyre pressure indicator will not come on as a result of over inflation."
Honda's use of the phrase "will not" suggests they're pretty certain about that. Whether that certainty still holds if the calibration hasn't achieved the required speed envelope isn't clear.