Tyre pressures "need adjustment"

[TonyFR]

RAV4 PHEV '21: I am getting warnings that the pressure in 2 tyres are low (2.2 bar cp 2.3 bar for the other 2) and need adjusting. The MFD shows me the pressures and when I have been travelling a while the pressures rise, of course. Even when they are all at 2.3 display still shows that those same 2 need adjustment. And if I stop and restart, I still get the message for those 2 tyres. If there were a fault with the sensors I would not expect to see the pressures displaying accurately, whether considered "incorrect" or OK. I changed to my winter tyres (on the same wheels) a few weeks ago but I cannot relate this directly to that event since the messages have only started to occur more recently. Is there a re-set mechanism?

[Roy124]

On your last, yes, there is a reset procedure.   I had to use it on my YC when I reset pressures from delivery to correct. 

[Nick72]

6 hours ago, TonyFR said:

RAV4 PHEV '21: I am getting warnings that the pressure in 2 tyres are low (2.2 bar cp 2.3 bar for the other 2) and need adjusting. The MFD shows me the pressures and when I have been travelling a while the pressures rise, of course. Even when they are all at 2.3 display still shows that those same 2 need adjustment. And if I stop and restart, I still get the message for those 2 tyres. If there were a fault with the sensors I would not expect to see the pressures displaying accurately, whether considered "incorrect" or OK. I changed to my winter tyres (on the same wheels) a few weeks ago but I cannot relate this directly to that event since the messages have only started to occur more recently. Is there a re-set mechanism?

Are the pressure transducers in the tyre as part of the valve assembly? Always wondered where they were but haven't been bothered to Google it.

Just wondering how it works when you change tyres?

[philip42h]

15 hours ago, TonyFR said:

Is there a re-set mechanism?

Accessed via the steering wheel control and instrument cluster > Vehicle Settings > TPWS > Set Pressure. See the OM section 2-1. Instrument cluster for full details.

Make sure that all four tyres are inflated to the correct pressure before doing a reset - the system simply takes the present values as definitive and sets the low pressure warning at a percentage lower ...

[philip42h]

9 hours ago, Nick72 said:

Are the pressure transducers in the tyre as part of the valve assembly? Always wondered where they were but haven't been bothered to Google it.

Just wondering how it works when you change tyres?

Yes - it's all built into the TPMS valve.

So all you have to do when changing a tyre is to NOT damage the valve when removing or refitting the tyre, and then simply pump the new tyre to the correct pressure.

Changing wheels is rather more problematic because the valves go with the 'old' wheels and the system needs recoding to recognise the new valves ...

[Nick72]

27 minutes ago, philip42h said:

Yes - it's all built into the TPMS valve.

So all you have to do when changing a tyre is to NOT damage the valve when removing or refitting the tyre, and then simply pump the new tyre to the correct pressure.

Changing wheels is rather more problematic because the valves go with the 'old' wheels and the system needs recoding to recognise the new valves ...

Philip,

This is good to know. 

Thank you.

Nick

[Cyker]

They just took the valves out of my old rims and put them in the new ones when I changed mine (I would have added new ones but they ere £72 each! That's more than the rims or the tyres!)

[Rambler56]

One trick to avoid erroneous cold weather alerts, inflate the tyres to 2psi less than required, reset TPMS, then put the additional 2psi in each tyre, giving you a couple of psi 'wriggle' room.  Some sensors are notoriously sensitive when tyres are set to the correct pressure and a temperature drop is enough to set them off.

[Nick72]

14 minutes ago, Rambler56 said:

One trick to avoid erroneous cold weather alerts, inflate the tyres to 2psi less than required, reset TPMS, then put the additional 2psi in each tyre, giving you a couple of psi 'wriggle' room.  Some sensors are notoriously sensitive when tyres are set to the correct pressure and a temperature drop is enough to set them off.

Great tip.

[TonyFR]

On 12/10/2023 at 9:42 AM, philip42h said:

Yes - it's all built into the TPMS valve.

So all you have to do when changing a tyre is to NOT damage the valve when removing or refitting the tyre, and then simply pump the new tyre to the correct pressure.

Changing wheels is rather more problematic because the valves go with the 'old' wheels and the system needs recoding to recognise the new valves ...

My tyres have been changed 5 times now on same wheels (summer > winter and reverse) with no problems for the sensors. My warning messages disappeared today as the temperature has risen from around zero to 12 and the tyres all went up 0.1 bar to celebrate. Think I'll go for Rambler56's tip!