Damn TPMS 😮

[MG Clive]

On my way round to a mate's to show off the new Xpower this morning, the tpms showed the n/s rear was low on pressure, so I stopped to have a look, it looked ok and it was only 236kpa whereas the rest were 240kpa, so I carried on.

It was still on when I got there, but then as I was going through a few things with my mate, it randomly went off. Had a cuppa and a chat etc, then an hour later I came home, tpms ok until I got home and the damn thing came on again.

Anyway, I put a bit of air in the tyre, but I couldn't get the warning to go off no matter how much air I put in the tyre, or let out, and no matter how much I drove round with different pressures in the tyre.

But the daftest thing is that you don't appear to be able to manually reset it, or even change the units to psi or bar.

I'm quite flummoxed, is this just one of those quirky MG things, or is there a known fault or cure for this?

 

[siteguru]

As a test I'd suggest to slightly over-inflate each tyre (then return to normal setting after the test) in turn and go for a short drive - see which tyre on the display shows the higher pressure.

My guess is that the wheels have been off for some reason and haven't been fitted back to the correct corners. (Each TPMS sensor is hard-coded to the car to represent a corner ... so if the left front and rear were swapped for example then a higher pressure added to the LF wheel would show in the car as the LR wheel).

 

[JonnyG]

It's very annoying !! but I've found inflating them all to around 270kpa and then driving regularly at that pressure for a week the warning eventually goes away. 270kpa is OK in the heavier Xpower IMHO and maybe good at reducing the the vibe too (see other posts). As you say there is no way to manually reset. So to check you don't have a faulty sensor you will need some testing at higher pressures.

 

[siteguru]

Interesting that you're both talking about pressure in kPa ... the UK cars usually show pressure in bar. (kPa is probably more useful, as you at least get a bit more granularity vs 0.1 bar which is 10 kPa ... your displays are probably updating at 4 kPa intervals which is 0.04 bar)

 

[JonnyG]

Yep, they round to the nearest 4 kPA on mine. I pump mine up to just over 39psi when cold (& doublecheck with another pressure guage) and the car dash still does'nt update for ages, and even then still shows a slightly lower equivalent kPA (around 260 /264). However I hav'nt had any warnings so happy days

 

[MG Clive]

Thanks guys, I've actually inflated them all to 38psi, so I'll see how it goes from there. If there was a bloody tpms fuse I'd chuck it in the bin.

 

[JonnyG]

Yeah I like the VW system (Mk 7 & 8) better where there is no TPMS, you can reset the pressures manually and any underinflation is still detected by the speed and rotation. It meant you could swap tyres around and also swap to a second set of Winter alloys/tyres with no hassle

MG would have been better spending the money on interior lighting rather than TPMS system IMHO !!

 

[tsedge]

Yeah I like the VW system (Mk 7 & 8) better where there is no TPMS, you can reset the pressures manually and any underinflation is still detected by the speed and rotation. It meant you could swap tyres around and also swap to a second set of Winter alloys/tyres with no hassle

MG would have been better spending the money on interior lighting rather than TPMS system IMHO !!

Yes it is better for that, but I always found the VW system annoying: "Somethings wrong with one of the tyres" meant I had to stop and check them all rather than be able to check the pressures on the screen and decide whether to keep driving.

 

[rjhfandclf]

I have exactly the same problem, which started several months ago, and it's on my list for the 1st service next week. It's totally random and bizarre - usually either or both rear wheels, and when checked on the driver's screen or the app, it will frequently show the front tyres as being identical or marginally higher/lower by 1 x 4-kPa notch (I don't know what the tolerance is before triggering the warning) while app only occasionally shows anything variable as it has rounded bars! Manual checking shows totally different readings but all identical. This happens either at set-off, or after short or long trips. NB The wheels have never been swapped around in its first year.

I will see what Perkins in Rayne say, and also get them to check the pressures all round to check my own Wolf pump for accuracy. They say they will do a software update for other issues (but not sure if relevant to this issue). I'll report back if anything of interest.

NB My old Mercedes TPMS was always spot-on.

 

[Wildthing]

My Xpower showed a low pressure after just 10 miles on the way Home after purchasing the car new. I checked all the tyres and found them all at the same pressure! Since then it regularly shows the same fault on the very same O/S/R, even though though the car has had all new wheels and tyres! (upgraded to 20" OZ wheels with 255/35/20 tyres) which it's had since just one month old. I just can't see why I cannot travel more than 20 or so miles without this fault showing. Obviously the new wheels were fitted with new TPMS valves. I can only think it must be the cars computers at fault. I will agree it is better running at 40psi, although I have never had the dreaded vibes.

 

[MG Clive]

Weirdly I had the warning for the o/s rear yesterday, and it went off after the next stop/start, so I know I don't have any punctures. I'm putting it down the over sensitive sensors due to the colder weather and subsequent lower pressures, so I'm ignoring it as a fault.

 

[cjmillsnun]

Interesting that you're both talking about pressure in kPa ... the UK cars usually show pressure in bar. (kPa is probably more useful, as you at least get a bit more granularity vs 0.1 bar which is 10 kPa ... your displays are probably updating at 4 kPa intervals which is 0.04 bar)

Mine is a UK MG4 Trophy ER and shows in kPa.

 

[cjmillsnun]

Yeah I like the VW system (Mk 7 & 8) better where there is no TPMS, you can reset the pressures manually and any underinflation is still detected by the speed and rotation. It meant you could swap tyres around and also swap to a second set of Winter alloys/tyres with no hassle

MG would have been better spending the money on interior lighting rather than TPMS system IMHO !!

TPMS is a legal requirement on new cars now I believe.

 

[John1941]

Happens cold weather short runs. Reported at my first service and sorted.

 

[Bricktop X PWR]

My Xpower showed a low pressure after just 10 miles on the way Home after purchasing the car new. I checked all the tyres and found them all at the same pressure! Since then it regularly shows the same fault on the very same O/S/R, even though though the car has had all new wheels and tyres! (upgraded to 20" OZ wheels with 255/35/20 tyres) which it's had since just one month old. I just can't see why I cannot travel more than 20 or so miles without this fault showing. Obviously the new wheels were fitted with new TPMS valves. I can only think it must be the cars computers at fault. I will agree it is better running at 40psi, although I have never had the dreaded vibes.

Get yourself over here pal and post up some photos!

MG4 X Power Roll Call and mods.

 

[mikgle]

Yeah Im having the warnings come on occasionally, always seem to be the rear ones especially the offside rear.. about 2.4 bar cold it comes on. I inflate them to about 2.5 / 2.6 and this seems to solve it. Happened a couple of times over the last few months but we have done a few long trips,
Often on the app it shows 0.0 bar, even though it says no abnormal faults on start up.
I will be sure to notify the garage at the next service in January and see what they say, and report back in due course..

 

[mikgle]

Happens cold weather short runs. Reported at my first service and sorted.

What did the garage do to sort it? is there some sort of calibration they can do?

 

[rjhfandclf]

I will see what Perkins in Rayne say, and also get them to check the pressures all round to check my own Wolf pump for accuracy. They say they will do a software update for other issues (but not sure if relevant to this issue). I'll report back if anything of interest.

Well, I just got the car back from its first service - which I have to say Perkins delivered without blemish - full software updates and every query looked-into. The TPMS was high on the 'niggle' list, and their response was exactly as has been proposed by others above - but moreso. They said that the problem occurs when pressures are set too low (I had checked all mine at 250 kpa immediately before the service). They further advise for all Trophy and X-Power cars with the 18"+ wheel sizes to pump them up to 3 bar (300 kpa) or 43.5 psi all round - which they say that they did ...

... However; there is still a small issue with this in that although the car now shows 300 kpa on the screen, I have since checked the tyres to see if my pump agreed - and it didn't - and neither did the pump supplied in the car's tyre repair kit, nor two manual gauges that I also tried ... all agreeing at 285 kpa / 41.5 bar. So I suspect that maybe the garage used either the car's screen for measurement (unlikely and probably impossible with the car motionless), or their own pump gauge is wrong. After four separate equipment tests, one tends to suspect that the car's TPMS reads about 5% high (in my case).

Either way, at least the TPMS hasn't so far faltered since is it stands, so I will leave well alone and just monitor it. The other more important factor from all this is that the service report showed that all the tyres were also 0.5 mm more worn (after only 4,500 miles) along both edges - most likely due to underinflation - so hopefully that should also at least get no worse now.

 

[salty]

Interesting, I know 40 psi, all round is recommended on here, and can ease the vibe problem on X Power's. But they are saying, 43.5 psi all round. Could be worth a try.

 

[dsimpkins]

Anyway, I put a bit of air in the tyre, but I couldn't get the warning to go off no matter how much air I put in the tyre, or let out, and no matter how much I drove round with different pressures in the tyre.

How far did you drive as it won't detect the change in pressure until it's covered enough distance. Had same thing after a recent puncture repair. It wasn't until I'd driven for about 0.5 mile before it cleared the warning.