Low pressure tyre warning

[fnegroni]

Before (warning) & After photos (cleared). Not triggered today, 18deg ambient.

Thank you, but you didn’t show the alarm text
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[tsedge]

The system seems a bit weird.

I had an MG4 hire car in France recently and its tyres were low (and inconsistently inflated), one tyre was at 2.3, two at 2.4 and one at 2.5 (when cold). Weirdly the system complained about the tyre at 2.5, not the 2.3 tyre!

I suppose it is possible the tyres had been swapped onto the wrong wheels but it had only done 10,000km.

 

[Rolfe]

Or just blow them up to 2.6 bar all round, forget about it and enjoy the car.

You'll still get the warnings if you do that. 2.7 seems to work for me.

There will be a hundred threads just like this in the next few weeks now we are going into autumn and the ambient temperature is dropping...

Just put a bit more air in all of the tyres, as they are just on the threshold of triggering the warning and when it is cold they drop just enough to set the warning off/

There is already a long thread on this subject

Low pressure tyre warning

Last night on my way home I suddenly got a low pressure tyre warning. When I called up the tyre pressure screen all the tyres were at 2.4 or 2.5 BAR, including the one that is supposedly low. When I scanned the car with the app this morning, same thing. Low pressure warning but all tyres...

www.mgevs.com

All new threads on this WILL be merged into this one, and posters invited to read the entire thing...

 

[fnegroni]

All new threads on this WILL be merged into this one, and posters invited to read the entire thing...

As punishment for their sins. ?

 

[Rolfe]

Precisely.

 

[StuartMG]

Had searched for a thread similar to the problem my MG4 LR seems to be having right now and infact seems to have had a number of times before! For the last few weeks at least I've been reminded multiple times about the right rear tyre being low when in reality it's not (inspected visually and it's not apparently different than any other). The car has always hated the back rear right tyre and has told me before about it being low when it hasn't had an issue or puncture. It seems to tell me if it's lower than 2.4 bar but will then on the move rise in line with the others, e.g to 2.5 bar and sometimes switch off (or not!) This is usually always on start up not when the car has been going for any duration.

More recently I'm now being told the back left is also an issue. Again all the readings are roughly around 2.4-2.5 bar each tyre. As before, I inflated all the tyres a little bit more recently to try and reset the warning and this worked for about 1 week before the warnings have come back again.

To not get complacent I do regularly check the tyres physically but I'm getting a bit fed up with it now. Seems to be far too sensitive to natural day to day changes a typical car tyre would be expected to see. Reading some of the replies on this thread should I be aiming to just put it to about 2.7 bar and hope for the best? Is this a known issue for other users (and unlikely one MG has acknowledged I would guess)?

 

[tsedge]

Had searched for a thread similar to the problem my MG4 LR seems to be having right now and infact seems to have had a number of times before! For the last few weeks at least I've been reminded multiple times about the right rear tyre being low when in reality it's not (inspected visually and it's not apparently different than any other). The car has always hated the back rear right tyre and has told me before about it being low when it hasn't had an issue or puncture. It seems to tell me if it's lower than 2.4 bar but will then on the move rise in line with the others, e.g to 2.5 bar! This is usually always on start up not when the car has been going for any duration.

More recently I'm now being told the back left is also an issue. Again all the readings are roughly around 2.4-2.5 bar each tyre. As before, I inflated all the tyres a little bit more recently to try and reset the warning and this worked for about 1 week before the warnings have come back again.

To not get complacent I do regularly check the tyres physically but I'm getting a bit fed up with it now. Seems to be far too sensitive to natural day to day changes a typical car tyre would be expected to see. Reading some of the replies on this thread should I be aiming to just put it to about 2.7 bar and hope for the best? Is this a known issue for other users (and unlikely one MG has acknowledged I would guess)?

When you drive the tyres get warmer and their pressure increases - this is normal
and expected which is why setting tyre pressures should be done when they are cold.

If you set them to 2.6 or 2.7 it should resolve the problem.

Precise tyre pressures don't matter for road cars. Yes, if you were track racing in a formula, you'd want to get them right, but even in track racing there's a zone in which tyres work well and pressures and temperatures vary a fair bit within that.

Nothing bad is likely to happen if you pump them up a little more.

 

[Rolfe]

Had searched for a thread similar to the problem my MG4 LR seems to be having right now and infact seems to have had a number of times before! For the last few weeks at least I've been reminded multiple times about the right rear tyre being low when in reality it's not (inspected visually and it's not apparently different than any other). The car has always hated the back rear right tyre and has told me before about it being low when it hasn't had an issue or puncture. It seems to tell me if it's lower than 2.4 bar but will then on the move rise in line with the others, e.g to 2.5 bar and sometimes switch off (or not!) This is usually always on start up not when the car has been going for any duration.

More recently I'm now being told the back left is also an issue. Again all the readings are roughly around 2.4-2.5 bar each tyre. As before, I inflated all the tyres a little bit more recently to try and reset the warning and this worked for about 1 week before the warnings have come back again.

To not get complacent I do regularly check the tyres physically but I'm getting a bit fed up with it now. Seems to be far too sensitive to natural day to day changes a typical car tyre would be expected to see. Reading some of the replies on this thread should I be aiming to just put it to about 2.7 bar and hope for the best? Is this a known issue for other users (and unlikely one MG has acknowledged I would guess)?

The answer is to inflate the tyres to 2.7 bar cold. It's not too much, and bye-bye warning pings.

I had my first ping of the season 30 miles into a 950 mile road trip in mid-August! I had one or two more after that, always when the ambient temperature had dropped. The tyres were all showing 2.5-2.6 bar. I got out my foot pump, got them all to 2.7 bar, and no trouble since. It will be interesting to see what happens when the evenings start to get really cold. It may be that "2.7 bar cold" will need to be re-assessed in terms of what "cold" actually means. But this works.

 

[fnegroni]

For the record this is the tyre gauge I use and matches the tpms sensor with enough accuracy I never get any warnings. I keep my tyres at 37 psi ambient temp. Measured when cold in the early mornings

https://amzn.eu/d/eAMcU0u

 

[Ian Key]

For the record this is the tyre gauge I use and matches the tpms sensor with enough accuracy I never get any warnings. I keep my tyres at 37 psi ambient temp. Measured when cold in the early mornings

https://amzn.eu/d/eAMcU0u

Yes it's worth getting an accurate tyre gauge. I now know my digital tyre inflater reads high so I set it at 2 psi more than I want to compensate.

 

[Rip Van]

Yes it's worth getting an accurate tyre gauge. I now know my digital tyre inflater reads high so I set it at 2 psi more than I want to compensate.

I use an old footpump to do my tyre pressures with the dial set to about forty and check it with a digital topeak(38psi).

 

[siteguru]

My digital compressor seems to be fairly accurate ... I set it to 37.5 psi and the car reads 2.6 bar (after a relatively short distance of movement, so minimal heating applied).

 

[benflugel]

Mine bonged this week with the lower temps. I've pumped them up to an indicated 2.7 on my pump. Oddly, car the car reads 2.6 for the front two and 2.7 for the back which is fine.

Bongs and warnings gone.

But yes, mine was similar to others. One single tyre reporting 2.5 was the culprit despite the one other showing 2.5 and the other two as 2.4. Who knows what it's looking for!

 

[apndavies]

Hello

Apologies if this has been discussed, but am baffled as to why I get low pressure warnings on some tyres, but not others, when the reported pressure is identical?

ALso - am I right in saying 2.6 bar is the pressure it should be?

Andrew

 

[Rolfe]

Merged. Have a read of the above thread.

I had my second warning of the season on Tuesday. The first was on 20th August, after which I pumped them all up to about 2.7 bar and all was well. But here we go again. All the tyres showing lower than I had them, cold weather of course.

I pumped them all up to what looked like just over 2.7 bar on my pump, but when I started to drive the car they were all showing 2.6 bar. That went up to 2.7 bar after a bit, and 2.8 bar before the end of the trip. Anyway, it's shut the warnings off. For now.

I was always pretty lackadaisical about tyre pressures. Just left it to the garage at servicing and MOTs. Or with the Golf, with its single warning light telling you neither which tyre nor how low, got the garage to check it when it bonged. The MG4 sure has ways of making you pay attention and keep those tyres the way it wants them.

 

[JonnyG]

It would be well worth everybody in the UK pumping their tyres up a touch now it has got a lot colder (0c here in Leeds last night?).

It will save a lot of similar posts about the warning !??

I usually have mine at 39psi (Xpower thing = 2.7 bar)) and they had all droppped to 36psi yesterday morning.

 

[Anon70]

Probably something as simple as two different teams writing the code for different bits of the system

Tyre pressure display team brief
Round any tyre pressure reading to 1 decimal place

Tyre pressure warning team brief
Use the absolute reading from the tyre monitoring system to trigger a pressure warning when pressure less than 2.30

Add those together and you get pressure warnings when the monitor is recording 2.25 to 2.29 but displays of 2.3

 

[Rolfe]

It would be well worth everybody in the UK pumping their tyres up a touch now it has got a lot colder (0c here in Leeds last night?).

It will save a lot of similar posts about the warning !??

I usually have mine at 39psi (Xpower thing = 2.7 bar)) and they had all droppped to 36psi yesterday morning.

I'm tempted to make this thread sticky for a bit!

 

[securespark]

How would you know they have actually put nitrogen in and not air which is 78% nitrogen anyway.

Yeah!

Donkey's years ago when I had a Maestro VdP, I used to get Hankook tyres from Selecta Tyre in Buxton. This must have been some time between 1990 and 1994.

They offered me Nitrogen and I tried it once. But, as you say, air is mostly Nitrogen anyway and I didn't think it was worth the extra.

 

[georgeOfCentralCoast]

Yeah nitrogen is not worth it. Unlike an aircraft, I don't store my tyres at sub zero temperatures and then expect stable pressure under a sudden emergency brake (landing). Nor do I have more than one brake disc rotor, the one I do have is much better ventilated and so I don't expect my tyres to explode by design due to brake disc heat during a rejected take off at full weight, so the 19% oxygen and water vapour in them is not much of an issue at all.