False TPMS Alert

[MakaveliX]

Was driving down a long A-Road this morning when my TPMS light came on, so did the safe thing and came off at the next junction and checked the tyres.
They were all 3 PSI over what they should be. ( Fronts should be 35, rear should be 33, but they were Front 38 and Rear 36 ) I then reset the TPMS light once the tyres had cooled down back to 35 front 33 rear

I monitor my tyre pressure closely every week so I never over or under inflate.

This is the second time since owning the car this has happened, it wasn't a particularly hot morning ( if anything quite cold ) and I had only been driving for 25 mins or so at 50mph.


Any advice regarding this ? As It's a horrible feeling to be going down a long A-Road or even motorway and then the TPMS light comes on.

Perhaps ensure the tyres are 35/33 go for a drive and then hit the TPMS set button after they have warmed up ?

I have indirect TPMS ( Mazda 3 ) which doesn't tell you the pressures via the infotainment but I believe it measures wheel rotations via the ABS sensor

[MakaveliX]

georgeyboy12345 said:

Take it to a tyre shop and have them check. I bet you have a nail in one of them

The tpms system also gives an alert when the pressure increases, that's why it went off. It has happened before on a very hot day.

[MakaveliX]

T6 vanman said:

Or you may have a tiny air leak

No air leak. When I got home and the tyres had cooled down, all the pressures were spot on.
As said, it seems to give an alert when the pressure either increases by 3 psi or of it decrease by 3psi. In todays instance it had increased by 3psi and then I got the alert

[MakaveliX]

Shaw Tarse said:

Same car as here and https://www.pistonheads.com/gassing/topic.asp?h=0&...

I knew I made a thread about this before but couldn't find it, thanks

I'll take the advice and go for a short drive then set the tpms

Still begs the question as to how all of my tyres had increased by 3psi on a cold morning at 50mph.

I've driven much longer journeys before and never had that alert.

Edited by MakaveliX on Sunday 26th February 17:10

[MakaveliX]

Aunty Pasty said:

The psi going up during a drive is quite normal. The axle rotation TPMS system is looking for differences between rotation speeds between wheels on the same axle.

Thanks for the info.
I checked them immediately and it was 38psi both at the front, and 36psi both at the rear.

Once I had left the car for a couple of hours they had returned to the standard of 35 psi front and 33 psi rear.

[MakaveliX]

Cool thanks guys. Not gonna lie I did panic when it came on as of all the places it was a fast and long A-road

What I don't get is, I've driven for hours before and had no alert however I drive for 25 minutes this morning and it gives an alert. Perhaps it had something to do with the atmospheric pressure.

So basically if it happens again just pull over at the next safe space, ideally service station or the next exit off the motorway/carriageway ( not hard shoulder) and give it a good check. I do have greenflag as a safety net. I also check my tyres without fail every week

[MakaveliX]

cuprabob said:

We know

Perhaps when the alert came on one tyre was at a different rotation and then shortly after when it warmed up they were the same, hence why the pressure on the front axle was the same and the pressure on the rear was the same when I checked a few minutes later.

[MakaveliX]

cuprabob said:

.. or perhaps youre over thinking it

Just keep checking your pressures regularly, as your doing, and accept the system is fallible.

Fair enough thanks

[MakaveliX]

mrmichaelsankey said:

.

Could be a sensor issue? I note yours may be based on rotation? Abs sensor playing up?

No issues I don't think.
If any one tyre fluctuates by 3psi, up OR down, it gives an alert. Just the way it works I think. Annoying because it can give a false positive if the tyre pressures increase during a journey

[MakaveliX]

Byker28i said:

Welcome to MAzda TPMS - we had a nightmare with our Mazda 6 over our many years of ownership.

They are really sensitive to differences between tyres. Mazda have a solution where they reset the system then take it for a constant 50mph drive for 20mins, but it didn't cure ours. It was in and out for years trying to fix the fault. In the end we just used to ignore it and mute it everytime. Terrible system.

You do have to make sure you change tyres on the same axle at the same time, expensive if you get a puncture. Mazda's solution suggested to us was to change all 4 tyres - at £200 for each wheel!

Thank you for the helpful information. Yeah these mazdas are great to drive but do have their own flaws ( as I'd assume most cars do )

Tyres are all pretty much brand new Michelin PS5s.

At least you can empathise how annoying it was to worry thinking I had a flat tyre when everything was completely fine.

3 times since owning the car the light has come on, and only once was it actually correct. Owned the car for 4 months

First time down country roads the tyres got hot and gave a false alert.
Second time was a lifesaver because I actually did have a fast puncture which thankfully got fixed
Third time was yesterday down an A road when it was a false alert

Difficult to just ignore it, especially on fast roads where you have to wait for an exit to actually check the tyres and not knowing whether it's another false alert or not.

If only it had direct tpms where you can monitor the tyre pressures via the cars infotainment system. That would be an ideal solution

[MakaveliX]

cuprabob said:

You're making the assumption those systems don't have issues as well.

Are they not more reliable generally though?

[MakaveliX]

Happened again today.
20 minutes down the motorway the light comes on. Got to my destination 25 minutes later, tyre pressures were all fine.
Reset the light, drove home, no tpms light. Same as last time

Would it be best to take it to an indy or would it have to be mazda ? I am under warranty, but their "diagnostic" charges are ridiculous.

The only pattern I can see is when driving around town, no issues. But if I set off on a longish journey on the motorway or a-road, the light comes on half way there.

I have no tpms valves, it's the indirect system which uses the ABS sensor I believe.

[MakaveliX]

As usual No light for 10 days or so. Until I hit the same long A-Road today and it came on.

Driving round town, no light. Driving on fast long roads, light comes on

The baffling thing is, it comes in on the way there, then i turn the light off and it stays off for the whole journey back

Worth contacting mazda or not?

Edited by MakaveliX on Sunday 12th March 17:45

[MakaveliX]

cuprabob said:

No, as I doubt they will be able to resolve it.

Sadly, I think you are just going to have to live with it.

Understood, thanks

[MakaveliX]

TGCOTF-dewey said:

The Honda systems are utterly awful. They're a well known issue. Mine goes off on EVERY long drive.

They're more dangerous than not having one.

Yeah same here with the Mazda.
Most my driving is short local journeys so it is not a big deal.

But if I hit the A roads for over 25 minutes or the motorway, the light usually comes on.
Can be a bit worrying just ignoring it - but suppose the best thing to do is just check the pressures before any long drive ( which is what I do now for peace of mind )

[MakaveliX]

Weird thing with mine is...
Long drive on the way there light comes on... Reset light.

On the way back, light doesn't usually come on ?

Maybe it's because my car prefers the drive to a destination and not from

[MakaveliX]

I agree it can be dangerous and that is why I made this thread.

All I do now is check me pressures regularly, make a note of them, and before any motorway or long journey check the tyres with a digital gauge then ignore the light if it goes off.

Seem to get less false alerts when the weather is warmer. But even when I do get them it's always always on long journeys

[MakaveliX]

Seems as though I was not calibrating it properly.
The correct procedure is to pump the tyres up to the desired pressure, hit the TPMS button, then go for proper drive ( ideally 50mph for 15mins ) and that should sort it.

What I was previously doing, was hitting the TPMS button then driving 10 mins down the road and therefore was not calibrating properly.

IF anything was off with the ABS sensors, then there would be error lights and the TPMS light would come on at random times, not just when on a longer journey down the motorway.

Seems alright now but will keep an eye on it.