Tyre pressure sensors really sensitive to cold weather .is300h

[Colinb623]

Has anyone noted this ? It took me 3 attempts this morning to erase the tyre pressure warning light off the dash with the reset button due to the cold weather 

[LenT]

10 minutes ago, Colinb623 said:

Has anyone noted this ? It took me 3 attempts this morning to erase the tyre pressure warning light off the dash with the reset button due to the cold weather 

Yes, I’ve had the same warning on very cold mornings.  Usually disappears once the tyre warms up.  On one occasion it LED to my having the tyre valve sheered off and having to have a new TPMS fitted!  But that’s another story….

 But I don’t think pressing the reset button is the answer.  The warning light is telling you that one - or more - of the tyres is under inflated.  The reset button simply resets the pressure limit to whatever the tyre is recording.  So you’re now driving around with under inflated tyres!

The only answer is to get to an air supply, check the tyre pressures and re-inflate to the correct levels.  If it keeps happening, check the tyre and valve for leaks.  

And maybe buy your own inflator?

 

[wharfhouse]

As above - you should not erase the light and just carry on - it's telling you one or more tyres are under inflated... This may be due to the cold weather as tyres will be down a few psi in the cold and can drop below the trigger threshold - especially if they were a bit low anyway. However you have now set the warning lower than what it should be for recomended pressures. Best solution now is to get a good tyre pressure gauge and inflate all the tyres (when cold - so don't drive to a forecourt and do it there - inflate at home after standing for a good few hours) to the recomended pressure and then reset the indicator again. Once set correctly if the light comes on again in future don't reset it - always first check the (cold) tyre pressures and inflate to the correct pressure - then you may need to drive around for a bit until the light goes out on its own after it does the relevant checks. 

[PaulWhitt20]

I have a slow puncture in one of my tyres. The tyre people can’t find anything in the tyre so I just check the pressure weekly and pump it up if necessary. I first noticed this in the very hot weather when the TPMS light came on, but if you check the pressures regularly and they are correct you don’t need to reset the TPMS. 

[LenT]

3 hours ago, PaulWhitt20 said:

I have a slow puncture in one of my tyres. The tyre people can’t find anything in the tyre so I just check the pressure weekly and pump it up if necessary.

How old are your tyres, Paul?

It’s not generally appreciated that after about six years - depending on usage and exposure to UV light - tyres start to deteriorate .  You should have a 4-digit code on the sidewall.  The first two digits indicate the week of manufacture , the second two the year.

[PaulWhitt20]

3 minutes ago, LenT said:

How old are your tyres, Paul?

It’s not generally appreciated that after about six years - depending on usage and exposure to UV light - tyres start to deteriorate .  You should have a 4-digit code on the sidewall.  The first two digits indicate the week of manufacture , the second two the year.

Not exactly sure, the cars outside in the cold, and I’m inside in the warm, plus it’s dark. However I did have a new set of CrossClimates before my MOT in July. So the tyres age isn’t the problem, but good suggestion. Thanks. 

[wharfhouse]

6 minutes ago, PaulWhitt20 said:

Not exactly sure, the cars outside in the cold, and I’m inside in the warm, plus it’s dark. However I did have a new set of CrossClimates before my MOT in July. So the tyres age isn’t the problem, but good suggestion. Thanks. 

I had a cracked rim on a BMW once that caused a slow leak - probably caused by hitting a pot hole...

[LenT]

36 minutes ago, PaulWhitt20 said:

Not exactly sure, the cars outside in the cold, and I’m inside in the warm, plus it’s dark. However I did have a new set of CrossClimates before my MOT in July. So the tyres age isn’t the problem, but good suggestion. Thanks. 

Yes, you’re probably right there!

Phil also makes a very good suggestion.  

Another thought is to check the valve ~ which you may have already done!  A little blob of washing up liquid should reveal any bubbling caused by a slow leak.  

And a missing dust cap is often the cause by allowing grit into the valve.

[matt8]

On 12/3/2022 at 6:43 PM, LenT said:

Another thought is to check the valve ~ which you may have already done!  A little blob of washing up liquid should reveal any bubbling caused by a slow leak.  

This was the cause of my slow leak, observed during a wash of the car (bubbles).

I had the local tyre shop fit this for me: https://lexuspartsdirect.co.uk/product/lexus-is-phase-3-tpms-fitting-kit/