Low pressure tyre warning

[purplemike]

Hi
My EV4 new Trophy has started to constantly warn me that two tyres need attention. However the car status check reports that all tyres are at the correct 2.4 and when I've taken it along to a garage to check them, none of the tyres need a top up.
Quite irritating......... any ideas thankfully received

 

[fnegroni]

The correct pressure is 2.5 not 2.4

 

[Pigeon]

Might be worth buying an accurate tyre pressure gauge to set the pressure precisely...some systems seem to be quite sensitive to differential pressures...even slight differences.

Last week I had a curtsey MG4 that did the same on the 2 rear tyres...topped up and went away....I think theres a sticker inside the drivers door with the correct pressure?

 

[siteguru]

37 psi is the standard pressure all round. The specs also say 2.5 bar, but 37 psi is actually 2.55 bar.

 

[Lovemyev]

TPMS systems are generally looking for any disparities in the increase / decrease of speed of one or more tyre, in relationship to the other tyres.
I have found on a few cars now, that a trigger point is usually caused when it detects a differential of about 2 - 4 PSI in a tyre.
Had the very same happen only 2 weeks ago while driving a 7 seater people carrier in America !.
TPMS was triggered, checked the pressures at a gas station and one of the rear tyres was about 3 PSI down on the other readings.
It had no facility to dismiss the TPMS light in the settings of the car.
After checking the pressures and topping up the affected tyre, the TPMS light went out on the next start up.
It never returned for the rest of your stay.
Man them things can eat the juice !.
15 MPG is about your lot .

 

[jonathan childs]

Hi
My EV4 new Trophy has started to constantly warn me that two tyres need attention. However the car status check reports that all tyres are at the correct 2.4 and when I've taken it along to a garage to check them, none of the tyres need a top up.
Quite irritating......... any ideas thankfully received

Our new MG4 SE is exactly the same, driving me bonkers

 

[Deleted member 14300]

Our new MG4 SE is exactly the same, driving me bonkers

The two rear tyres are same on mine.

 

[Rolfe]

I've merged this thread into the ongoing one about tyre pressure warnings, to keep all the information and advice in the same place and save everyone going through the same thing again.

Read back through the thread for the required information.

 

[tonybridge]

This yesterday

 

[Rolfe]

That's downright weird. Nearly as weird as the fact that, when I deliberately let air out of my left front tyre (to check the wheels hadn't been switched when the tyres were changed) the pressure went down to 2.2 BAR, but I didn't get a low pressure warning!

How come you get three significant figures on the app, anyway? (Sorry, I should have looked closer. Still weird though.)

 

[fnegroni]

This yesterday

Sorry I don’t see anything wrong with that.
Your tyres are all under 2.5.
The TPMS has some tolerance and three out of four are within that tolerance level but the rear tyre highlighted was outside of that.
The system is programmed in such a way that small fluctuations in pressure don’t trigger the warning, but they won’t cancel the warning either.
IME it works really well.
You better inflate those tires

 

[siteguru]

That's downright weird. Nearly as weird as the fact that, when I deliberately let air out of my left front tyre (to check the wheels hadn't been switched when the tyres were changed) the pressure went down to 2.2 BAR, but I didn't get a low pressure warning!

How come you get three significant figures on the app, anyway?

3? It only shows to 1 decimal place? Ideally it should show to 2. (Or show the pressure in psi without any decimal if necessary).

 

[Rolfe]

Significant figures are not the same as places after the decimal point. Look it up.

However, it seems I was reading the B of Bar as an 8.

And I had my annual eye test the day before yesterday, everything perfect! Oops.

 

[tonybridge]

Significant figures are not the same as places after the decimal point. Look it up.

However, it seems I was reading the B of Bar as an 8.

And I had my annual eye test the day before yesterday, everything perfect! Oops.

Sorry I don’t see anything wrong with that.
Your tyres are all under 2.5.
The TPMS has some tolerance and three out of four are within that tolerance level but the rear tyre highlighted was outside of that.
The system is programmed in such a way that small fluctuations in pressure don’t trigger the warning, but they won’t cancel the warning either.
IME it works really well.
You better inflate those tires

Errr... what’s wrong with it is that there is nothing wrong with it….

 

[Rolfe]

Exactly. All the tyres are fine, and yet the flag says "abnormal". Ghosts in the machine again.

 

[fnegroni]

Exactly. All the tyres are fine, and yet the flag says "abnormal". Ghosts in the machine again.

no the rear right is low. Lower than the others. It was provably at 2.3 when the warning was triggered, it came back up to 2.4 but to cancel the warning it is not sufficient.
Think of it as a trigger range: the pressure must dip below 2.35 to trigger the warning, but must rise above 2.45 to cancel it.

And more over, the TPMS sensor also measures how quickly the pressure drop took place.

Bottom line: put tyres back up to 2.5 and keep an eye on the one reported.

 

[GaryMG4]

Had the same happen tonight after going to the theatre, right rear low but all showing 2.4 warning remained all the way home but it was 1 degree outside. Ill check them in the morning and add another .1 bar and see how it goes.

 

[tonybridge]

no the rear right is low. Lower than the others. It was provably at 2.3 when the warning was triggered, it came back up to 2.4 but to cancel the warning it is not sufficient.
Think of it as a trigger range: the pressure must dip below 2.35 to trigger the warning, but must rise above 2.45 to cancel it.

And more over, the TPMS sensor also measures how quickly the pressure drop took place.

Bottom line: put tyres back up to 2.5 and keep an eye on the one reported.

So… what is the point of this warning, if the displayed values are wrong?! This was yesterday, today there was no warning - and I haven’t put a few Bars into the tyre overnight.

 

[Rolfe]

no the rear right is low. Lower than the others. It was provably at 2.3 when the warning was triggered, it came back up to 2.4 but to cancel the warning it is not sufficient.
Think of it as a trigger range: the pressure must dip below 2.35 to trigger the warning, but must rise above 2.45 to cancel it.

And more over, the TPMS sensor also measures how quickly the pressure drop took place.

Bottom line: put tyres back up to 2.5 and keep an eye on the one reported.

Oh, I see.

Weirdly, when I let a tyre down to check the left-hand ones were on the right axles, the display went to 2.2 but I never got a low pressure warning.

So… what is the point of this warning, if the displayed values are wrong?! This was yesterday, today there was no warning - and I haven’t put a few Bars into the tyre overnight.

It got warmer and the pressure rose. But it's likely to go off again next time it gets cold. Better get them all up to 2.5 cold. That'll stop it.

 

[fnegroni]

Oh, I see.

Weirdly, when I let a tyre down to check the left-hand ones were on the right axles, the display went to 2.2 but I never got a low pressure warning.

Was that a front or rear tyre?