Tyre Pressure Monitoring Weird Behaviour

[LukeTim]

I’ve just put some air into my tyres for the first time as they were a bit low and I have a long drive coming up very soon, I found the manual says 2.5 bar/37 psi so I put 37psi into each tyre.

I’ve now scanned the car with the app about 30 minutes later and it’s now saying my tyres are at 0 bar! Curiously it’s not reporting any abnormalities.

There’s definitely nothing wrong with the tyres so I’m guessing this is an issue with the software/tpms. I did just plug in the granny lead I don’t know whether charging has an effect on the scanning.

Will this resolve itself over time or have I got a dud tpms?

 

[webhiker]

Not difficult to analyse.
What does the car main screen report as the tyre pressure?
What does the tyres look like? Totally flat?

A reading of zero indicates no connection

 

[Diggsy]

Did you drive it after filling the tyres? It won’t reset until driven for a short distance

Also - might need a tad more air in them. From memory, 2.5 is on the limit where it might start telling you the pressures are low

 

[AndyL61]

I’ve just put some air into my tyres for the first time as they were a bit low and I have a long drive coming up very soon, I found the manual says 2.5 bar/37 psi so I put 37psi into each tyre.

I’ve now scanned the car with the app about 30 minutes later and it’s now saying my tyres are at 0 bar! Curiously it’s not reporting any abnormalities.

View attachment 30279

There’s definitely nothing wrong with the tyres so I’m guessing this is an issue with the software/tpms. I did just plug in the granny lead I don’t know whether charging has an effect on the scanning.

Will this resolve itself over time or have I got a dud tpms?

When it's charging for reasons unknown the tyre pressures show zero , also interior temperature shows zero. Take it off charge and rescan and everything will appear normal again. Mine does this.

 

[LukeTim]

When it's charging for reasons unknown the tyre pressures show zero , also interior temperature shows zero. Take it off charge and rescan and everything will appear normal again. Mine does this.

Thanks, that was the issue. Off charge all is normal.

 

[fnegroni]

Also - might need a tad more air in them. From memory, 2.5 is on the limit where it might start telling you the pressures are low

2.5 is the right pressure.

What most people get wrong is that they expect the pressure to stay the same day and night, and inflate tyres when it’s sunny.
As a result the tyre pressures will be all over the place, plus at night the pressures will go lower and then the readout on the screen will update but the sensor has already detected the tyre was under inflated, because it was, given the temperatures dropped and the pressure was too low when the sensor took the readout of temperature and pressure.

Inflate to 37 psi in the early morning before sunrise, or evenings if car hasn’t been used for a few hours, and you’ll be fine… until the temperatures drop again. At which point you will need to do the same.

And then the temperatures will rise, and you will once again have to adjust them.

Of course one could simply massively overinflate them all and then instead of complaining about the TPMS, complain about handling, unusual wear and tear, etc etc…

 

[AshXP]

With the current temperatures ranging from 3 degrees to 18 degrees in the UK, this will affect your Tyres pressure display/ readings dramatically. As the Tyres expand and contract (which is normal), if you visibly look at them, they will be fine, but do not inflate them because when they go back to normal they will be over inflated which is dangerous. Once they warm up, or the outside temperature adjusts or they reset from stop start they will go back to normal.

 

[Rip Van]

2.5 is the right pressure.

What most people get wrong is that they expect the pressure to stay the same day and night, and inflate tyres when it’s sunny.
As a result the tyre pressures will be all over the place, plus at night the pressures will go lower and then the readout on the screen will update but the sensor has already detected the tyre was under inflated, because it was, given the temperatures dropped and the pressure was too low when the sensor took the readout of temperature and pressure.

Inflate to 37 psi in the early morning before sunrise, or evenings if car hasn’t been used for a few hours, and you’ll be fine… until the temperatures drop again. At which point you will need to do the same.

And then the temperatures will rise, and you will once again have to adjust them.

Of course one could simply massively overinflate them all and then instead of complaining about the TPMS, complain about handling, unusual wear and tear, etc etc…

No need to "massively overinflate". Try 1psi extra (cold) and see how it goes. Tyre pressure can rise by quite a few psi during your day. Wouldn't worry about it.

 

[siteguru]

Rule of thumb ... tyre pressure changes between 1 and 2psi for every 10°C change in temperature.

 

[tsedge]

Yes, it is utterly pointless on road cars trying to get the pressure exactly right, it will vary anyway with load, temperature, driving conditions, driving style etc...

 

[Rolfe]

I’ve just put some air into my tyres for the first time as they were a bit low and I have a long drive coming up very soon, I found the manual says 2.5 bar/37 psi so I put 37psi into each tyre.

I’ve now scanned the car with the app about 30 minutes later and it’s now saying my tyres are at 0 bar! Curiously it’s not reporting any abnormalities.

View attachment 30279

There’s definitely nothing wrong with the tyres so I’m guessing this is an issue with the software/tpms. I did just plug in the granny lead I don’t know whether charging has an effect on the scanning.

Will this resolve itself over time or have I got a dud tpms?

Since nobody seems to have addressed the initial point, this is a bug in the app. Sometimes it reports all the tyres as being at zero pressure when there's nothing wrong. It clears by itself.

If one of the tyres is actually registering as being under pressure then that tyre will still be flagged though. It's only the zero pressures that are caused by the bug.

 

[Lovemyev]

On the ZS EV each wheel ? has its own, coin cell battery powered TPMS sensor system.
Each wheel / tyre then reports back to the TPMS module, which will consume the cell battery power over time.
If there is a consistent zero reading from one particular wheel / tyre, then this may suggest that the battery ( which is not replaceable ) or the sensor has failed.
Other manufacturers favour monitoring the tyre pressures via the ABS system.
The system is powered via the 12 volt battery and is constantly monitoring the speed of each wheel ? and when it detects a wheel / tyre that is turning constantly at a different rate, which could be due to a slow puncture etc, it flags up a warning to the driver.
On VAG models it appears to flag a warning to the driver, when it detects a 3-4 PSI differential in a single tyre.
I have a suspicion that MG have set a similar criteria regarding pressure warnings.

 

[AndyL61]

Since nobody seems to have addressed the initial point, this is a bug in the app. Sometimes it reports all the tyres as being at zero pressure when there's nothing wrong. It clears by itself.

If one of the tyres is actually registering as being under pressure then that tyre will still be flagged though. It's only the zero pressures that are caused by the bug.

The bug in the app is when charging. It reports zero tyre pressure and no internal temperature. Once off charge it reverts back to normal. My Trophy does this every time I charge.

 

[Rolfe]

I didn't notice any consistency to it, but you could well be right.

 

[fnegroni]

Neither have I. For example I haven’t seen the TPMS issue. Ever.

 

[John T]

I’ve just put some air into my tyres for the first time as they were a bit low and I have a long drive coming up very soon, I found the manual says 2.5 bar/37 psi so I put 37psi into each tyre.

I’ve now scanned the car with the app about 30 minutes later and it’s now saying my tyres are at 0 bar! Curiously it’s not reporting any abnormalities.

View attachment 30279

There’s definitely nothing wrong with the tyres so I’m guessing this is an issue with the software/tpms. I did just plug in the granny lead I don’t know whether charging has an effect on the scanning.

Will this resolve itself over time or have I got a dud tpms?

From time to time my MG4 gives an audible and worded warning that the rear offside tyre is low but the display chows all 4 up to 2.5 bar, with the rear offside in orange print. When I bought the car I queried with the dealership having used a pressure gauge but was told I'd have to pay silly money for diagnostics
if there was nothing wrong.

 

[Davn]

I’ve just put some air into my tyres for the first time as they were a bit low and I have a long drive coming up very soon, I found the manual says 2.5 bar/37 psi so I put 37psi into each tyre.

I’ve now scanned the car with the app about 30 minutes later and it’s now saying my tyres are at 0 bar! Curiously it’s not reporting any abnormalities.

View attachment 30279

There’s definitely nothing wrong with the tyres so I’m guessing this is an issue with the software/tpms. I did just plug in the granny lead I don’t know whether charging has an effect on the scanning.

Will this resolve itself over time or have I got a dud tpms?

Happens a lot, normally I just hit the refresh and it tends to come up or you can check from the dashboard

 

[Giller]

The bug in the app is when charging. It reports zero tyre pressure and no internal temperature. Once off charge it reverts back to normal. My Trophy does this every time I charge.

Spot on. ?

As has previously been mentioned tyre pressures must be checked on cold tyres, even driving a mile to a garage will make a change. I haves compressor in my garage with a calibrated gauge so can check cold tyres but bit of a faff getting it up to pressure and pulling out the airline so having spoken with a few tyre specialists (I’m in the bike trade), treated myself to a MICHELIN Top-up mini rechargeable Inflator Pump which they’ve recently released. Now other Inflator pumps are available but love the quality and features of this thing, had it calibrated and it’s bang on so once a week I’ll be checking cold tyres and ignoring the systems figures, though not the warnings. I’m daft, I’m not stupid. ?

 

[John T]

Happens a lot, normally I just hit the refresh and it tends to come up or you can check from the dashboard

Where is the "Refresh"?

 

[Giller]

Arrows in a circle on the left.