TPMS

[marineboy]

Out to shops today and shortly after setting off got message ‘front right tyre loss of pressure’. Stopped and checked the pressure, 33psi (normally 36). No obvious nail/damage. So continued (carefully) to shops and back home when I jacked the car up and had a good look all round the tyre. Again, nothing to see. So I inflated back to 36 and left it.  Just checked it again after 3 hours and no change. 
 

It’s possible that since I last checked it the tyre has lost pressure as they often do over time. Re the TPMS, I’ve had one or two false alarms in my Golf over my 11 years of ownership. I think that it works via the ABS sensor and can be activated if a tyre picks up some mud which alters its rotation characteristics but there was no evidence of that. 
 

Has anyone had a similar experience?

[Doofy]

Temperature can affect it 

[marineboy]

14 minutes ago, Doofy said:

Temperature can affect it 

Yes I get that but why just one tyre? Or did you mean the sensor on that axle?

[Ootohere]

How long ago were the pressures checked and set when cold, or similar temp til todays?

 

Good that it indicated a change since last checked pressure and the TPMS reset.

If reset now and all well good if it warns again if there is a change at some point.

 

It is just the circumference it knows, and a over heating bearing or sticky brakes can heat up a wheel / tyre, or sitting with the sun hitting a tyre.

The pressure was lower though so a win. 

[Seasider]

What pressure were the other three tyres, or didn't you check them?  If the front right tyre has a slow puncture, then eventually this may set off the low pressure warning.  I've had a number of false alarms over the years with my Fabia and Kamiq when going over an uneven bit of road at speed, e.g. an expansion joint on a bridge.

[Paws4Thot]

54 minutes ago, marineboy said:

Yes I get that but why just one tyre? Or did you mean the sensor on that axle?

There is an ABS sensor on every wheel. If only one tyre was (not) in the sunlight I'd expect it to be at a different pressure to the others.

[marineboy]

1 hour ago, Seasider said:

What pressure were the other three tyres, or didn't you check them?  If the front right tyre has a slow puncture, then eventually this may set off the low pressure warning.  I've had a number of false alarms over the years with my Fabia and Kamiq when going over an uneven bit of road at speed, e.g. an expansion joint on a bridge.

Yes I did check the other tyres. All at 36. And I’ve just checked the suspect one and it’s still 36. I’m thinking perhaps that it does have a VERY slight leak and over the last few weeks since I checked all the tyres its pressure has reduced to the point where it triggered the sensor. 

[Routemaster1461]

2 hours ago, marineboy said:

Yes I did check the other tyres. All at 36. And I’ve just checked the suspect one and it’s still 36. I’m thinking perhaps that it does have a VERY slight leak and over the last few weeks since I checked all the tyres its pressure has reduced to the point where it triggered the sensor. 

 

You normally need 6-8psi pressure loss to have the system give a warning. That is how it has been on all of my cars with indirect TPMS.

[Ootohere]

Not a hard and fast rule though.

Easy enough with an accurate tyre pressure gauge.   Set pressures, reset the TPMS then after all well let one down by 4 psi. 

There can be maybe a little pressure loss and some tyre tread wear, it is only the circumference and rotations of the wheel being measured.

 

A more sensitive system and a warning is a good thing as running 5 psi low because regular checks done is not 'Simply Clever'. 

[Warrior193]

On 21/02/2024 at 19:30, Routemaster1461 said:

 

You normally need 6-8psi pressure loss to have the system give a warning. That is how it has been on all of my cars with indirect TPMS.

My winters appear to be foreign body magnets, regular slow punctures from screws, etc 😒 - my TPMS reliably flags at approx. 0.5 bar / 7PSI.

Edited 22 February by Warrior193
add emoticon

[marineboy]

Interesting comments re the amount of pressure drop needed to trigger the warning, ie 6 to 8 psi. The fact that my offending tyre was only 3 below the others (and possibly a bit less than that), and there has been no further reduction in pressure over the last few days, leads me to think that the warning was triggered either by a bit of debris on the tyre or sensor or a software glitch. 

[Ootohere]

Or just because the pressure once home was only 3 psi lower than when set.  But maybe if you are a tyre pressure guage when the warning activated and checked pressures it might not have been only 3 psi.   This same subject comes up regularly.   Good actually people get random warnings because in the owners manuals it advises to do test checks.