Tyre Pressure Settings & TPMS warnings

This is what mine says, I'm getting the valve on the 0.0 tyre fixed this week

SmartSelect_20221121_133806_MG iSMART.jpg
 
I am going to make a guess that the TPMS system on the MG4 is very similar to the other MG EV’s.
A lot of TPMS systems work by each wheel constantly cross checking the speed differential between each wheel 🛞 and then triggers an alert if one wheel rotation conflicts with the preset settings, I believe.
A tyre that has a puncture will be traveling at a different rotational speed as the wheels which are reporting correctly.
On VAG group cars this is done via the ABS system, via a speed ring on each wheel hub.
If the recommend tyre pressure on a VAG group car was 36 PSI - but the owner had set ALL the pressures to a identical 40 PSI then reset the TPMS it would be happy, because they are all identical.
I my experience of the VAG & BMW system, are that they trigger when ONE wheel losses more than about 2 PSI over the other wheels, regardless of pressure they where set at.
But the MG system is different as it has a sensor built onto back of each of the tyre inflation valves on each wheel, powered by a coin cell battery in the sensor.
I have found that the MG system read outs do fluctuate around a fair bit, even on the same day !.
If the car is parked with one side of the car in direct sun light, the pressure read out in those two tyres will be higher.
As you would expect of course, but the system must have the capacity to adopt to this fluctuation, is what I am saying.
We had our first TPMS warning flag up about two weeks ago, in our ZS EV facelift.
Totally out of the blue and for no apparent reason ?.
One wheel triggered, then after a couple of minutes the other wheels started to trigger warnings ⚠️ one after the other !.
When I checked ALL of the tyre pressures, the one that first triggered was about 2 PSI down on the the other three, to be fair.
I reset ALL of the tyres and double checked them with TWO different tyre pressures gauges all reading bang on 41 PSI.
When I booted up the car, all four TPMS sensors where still triggering the alarm.
I was just about to set off for a drive ( to recalibrate the sensors ) but then all the warning ⚠️ lights went out and the bonging stopped.
The sensors has taken about 20 seconds to talk to the car and was happy with what it had seen.
The car had NOT even moved at this point !.
I know the pressures are bang on, but I did keep checking what the car was reporting.
Very close, but the was a sight difference between the pressures reported by the car.
We have not received any further TPMS warnings to-date.
Today the weather is extremely wet and a bit chilly.
I have just checked and the App reports that all pressures are absolutely identical, strangely enough.





B7965770-2E25-4B64-AD9C-3A213BA66431.jpeg
 
Lovemyev said:
I am going to make a guess that the TPMS system on the MG4 is very similar to the other MG EV’s.
A lot of TPMS systems work by each wheel constantly cross checking the speed differential between each wheel 🛞 and then triggers an alert if one wheel rotation conflicts with the preset settings.
Click to expand...
In that case, I'd be checking if all the tyres are the same size. 🤔
 
MiddletonMark said:
Hi Everyone,

How do I activate the TPMS display/info please?

MG4 SE

Mark
Click to expand...
It’s on the iSMART app when you press the ‘vehicle status’ button.

Otherwise if you want to see it in the car, it’s on the screen at the steering wheel. Press the button on the right of the steering wheel that looks like pages, then move the stick left or right to scroll through the screens ‘pages’. TPMS shows the tyre pressure there
 
Lovemyev said:
I am going to make a guess that the TPMS system on the MG4 is very similar to the other MG EV’s.
A lot of TPMS systems work by each wheel constantly cross checking the speed differential between each wheel 🛞 and then triggers an alert if one wheel rotation conflicts with the preset settings, I believe.
A tyre that has a puncture will be traveling at a different rotational speed as the wheels which are reporting correctly.
On VAG group cars this is done via the ABS system, via a speed ring on each wheel hub.
If the recommend tyre pressure on a VAG group car was 36 PSI - but the owner had set ALL the pressures to a identical 40 PSI then reset the TPMS it would be happy, because they are all identical.
I my experience of the VAG & BMW system, are that they trigger when ONE wheel losses more than about 2 PSI over the other wheels, regardless of pressure they where set at.
But the MG system is different as it has a sensor built onto back of each of the tyre inflation valves on each wheel, powered by a coin cell battery in the sensor.
I have found that the MG system read outs do fluctuate around a fair bit, even on the same day !.
If the car is parked with one side of the car in direct sun light, the pressure read out in those two tyres will be higher.
As you would expect of course, but the system must have the capacity to adopt to this fluctuation, is what I am saying.
We had our first TPMS warning flag up about two weeks ago, in our ZS EV facelift.
Totally out of the blue and for no apparent reason ?.
One wheel triggered, then after a couple of minutes the other wheels started to trigger warnings ⚠️ one after the other !.
When I checked ALL of the tyre pressures, the one that first triggered was about 2 PSI down on the the other three, to be fair.
I reset ALL of the tyres and double checked them with TWO different tyre pressures gauges all reading bang on 41 PSI.
When I booted up the car, all four TPMS sensors where still triggering the alarm.
I was just about to set off for a drive ( to recalibrate the sensors ) but then all the warning ⚠️ lights went out and the bonging stopped.
The sensors has taken about 20 seconds to talk to the car and was happy with what it had seen.
The car had NOT even moved at this point !.
I know the pressures are bang on, but I did keep checking what the car was reporting.
Very close, but the was a sight difference between the pressures reported by the car.
We have not received any further TPMS warnings to-date.
Today the weather is extremely wet and a bit chilly.
I have just checked and the App reports that all pressures are absolutely identical, strangely enough.





View attachment 12932
Click to expand...

No, you’re confusing different types of tyre pressure systems.
The system you describe that measures wheel rotation is a basic tyre pressure WARNING system, and will just tell you a tyre is soft by means of a warning light/sound.
These systems do not display pressures.
You’ve no clue how soft the tyre is until you use something external to measure it.

What the MG has, along with most other cars now, is a tyre pressure MONITORING system, that shows pressures live.
It appears the MG system does need some rotation of the wheels to kick the batteries into life and display pressures.
This seems to be a battery saving feature (each valve has its own wee battery)
Some cars will give you pressures even though the car is stopped.

Two distinctly separate systems.
One is a very basic warning that a tyre is softer than the rest
One actually tells you how much air is in each tyre at any given moment.
 
bowfer said:
The system you describe that measures wheel rotation is a basic tyre pressure WARNING system
Click to expand...
The VAG system works via the ABS system and has no TPMS battery powered sensors in each wheel.
It measures and compares the rotational speed across all four wheels in milliseconds and feeds that info back to the module and then back to the driver if it detects that one wheel is turning slower than the three other wheels due to a possible puncture.
It is good a detecting a fault, when there is a 4psi differential in pressure in that suspected tyre.
When a wheel rotation has taken place, there is no requirement for a relearn process.
TPMS system on the ZS EV Gen1 will require each sensor to be recoded to the new position on the car.
The improved system on the Gen2 model does have a relearn facility and no recoding is required to each sensor.
BMW uses a similar system as VAG via the ABS system.
 
bowfer said:
Two distinctly separate systems.
One is a very basic warning that a tyre is softer than the rest
One actually tells you how much air is in each tyre at any given moment.
Click to expand...
Agree. My old (2012) Golf had a warning system; my Insignia (and this MG4) are monitoring systems.
 
Lovemyev said:
The VAG system works via the ABS system and has no TPMS battery powered sensors in each wheel.
It measures and compares the rotational speed across all four wheels in milliseconds and feeds that info back to the module and then back to the driver if it detects that one wheel is turning slower than the three other wheels due to a possible puncture.
It is good a detecting a fault, when there is a 4psi differential in pressure in that suspected tyre.
When a wheel rotation has taken place, there is no requirement for a relearn process.
TPMS system on the ZS EV Gen1 will require each sensor to be recoded to the new position on the car.
The improved system on the Gen2 model does have a relearn facility and no recoding is required to each sensor.
BMW uses a similar system as VAG via the ABS system.
Click to expand...
Are you saying that this VAG system gives you a measure of tyre pressure (via the rotation/ABS)? If yes, HOW? Yes, it knows if one tyre is different to the others, but it can't know what the actual pressure is.
 
Lovemyev said:
The VAG system works via the ABS system and has no TPMS battery powered sensors in each wheel.
It measures and compares the rotational speed across all four wheels in milliseconds and feeds that info back to the module and then back to the driver if it detects that one wheel is turning slower than the three other wheels due to a possible puncture.
It is good a detecting a fault, when there is a 4psi differential in pressure in that suspected tyre.
When a wheel rotation has taken place, there is no requirement for a relearn process.
TPMS system on the ZS EV Gen1 will require each sensor to be recoded to the new position on the car.
The improved system on the Gen2 model does have a relearn facility and no recoding is required to each sensor.
BMW uses a similar system as VAG via the ABS system.
Click to expand...
Yes, that is how the VAG system works but as you've already said, the MG system is a different type - each sensor has a battery as bowfer has described.
 
siteguru said:
Are you saying that this VAG system gives you a measure of tyre pressure (via the rotation/ABS)? If yes, HOW? Yes, it knows if one tyre is different to the others, but it can't know what the actual pressure is.
Click to expand...
No, it doesn't, it just tells you that "a tyre" has low pressure. (That's my experience across 3 different VAG vehicles in recent years).
 
tsedge said:
Yes, that is how the VAG system works but as you've already said, the MG system is a different type - each sensor has a battery as bowfer has described.
Click to expand...
Yes I am aware that the MG sensors have a coin cell battery powering each sensor in each wheel, it was in the first line of my post 31 see above.
"The VAG system works via the ABS system and has no TPMS battery powered sensors in each wheel".
Therefore unlike how the MG system works, it requires a battery feed sensors in each wheel.
The VAG system has the ability to locate both the current AND future location of that wheel, if that wheel has been subjected to a wheel rotation, that is recommended every 5,000 miles by VAG.
BUT you are totally correct, the VAG system only has the ability to notify the driver of the correct position of any affected tyre by pressure loss.
It does NOT have the ability to display the actual tyre pressures figures to the driver, maybe I should have been a little clearer here sorry.
The TPMS system on the ZS EV differs even between Gen1 and Gen2 models.
Gen1 sensors have to be factory / dealer coded to THAT location on the car and will be fine if the wheel is removed ( say a puncture repair ) and then refitted to the very same location.
But you are unable to carry out a front to back rotation, without having to have the sensors recoded again.
So, in affect that wheel / sensor has to remain in that same location or you will need a recoded.
If the sensor develops a fault or the battery fails, it need recoding as it is unable to relearn the new position on the car.
 

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