Lexus on TPMS

[malcolmw]

I thought this was quite good coming from Lexus themselves:

http://blog.lexus.co.uk/tyre-pressure-monitoring-system-what-is-tpms-and-how-does-it-work/

 

[cruisermark]

" however some vehicles from other manufacturers adopt a more rudimentary indirect method that uses existing wheel speed sensors to ‘measure’ tyre pressure by detecting differences in the rate of wheel rotation. "

This is what they use in the LS430 !

[NemesisUK]

Don't they term the indirect system TPWS, a warning rather than monitoring system?

[Britprius]

The system with monitors in each wheel although not always utilised actually transmits more information than is usually displayed. The system not only transmits the real pressure "not just a low set pressure" it also sends a different code for each wheel, the tyre temperature, and the level of charge of the batteries for each sensor.

John.

[Ala Larj]

On 5/24/2018 at 1:32 PM, malcolmw said:

I thought this was quite good coming from Lexus themselves:

http://blog.lexus.co.uk/tyre-pressure-monitoring-system-what-is-tpms-and-how-does-it-work/

 

"If any appear to be deflated yet undamaged you should try to re-inflate them to the correct pressure and reset the TPMS (see subheading below)."

I had a slow puncture last year whilst on a touring holiday in Scotland where I was losing .5 and .7 bar overnight on one tyre. I just pumped it each morning and never reset anything. Didn't seem to cause a problem.

Also in the table it says that the GS reset is in the software menu but in my handbook it states that I have a button somewhere behind the steering wheel. 

 

 

[sorcerer]

On 5/24/2018 at 2:31 PM, NemesisUK said:

Don't they term the indirect system TPWS, a warning rather than monitoring system?

It must monitor the pressures so that it knows when to give a warning, so a case of "you say potato I say potato" methinks

[NemesisUK]

13 minutes ago, sorcerer said:

It must monitor the pressures so that it knows when to give a warning, so a case of "you say potato I say potato" methinks

No, don't think so. TPWS uses the rotational speeds of the wheels to determine the rolling circumferences. If a tyre deflates that circumference will change and so will the rotational speed. The TPWS doesn't know the tyre pressures, it just reacts to a change and it needs to be quite a significant change, approx 25% IIRC.

 

[rayaans]

And worth remembering that once you've set it, you don't need to keep doing it over and over again. 

Set it once and leave it be.

[sorcerer]

1 hour ago, NemesisUK said:

No, don't think so. TPWS uses the rotational speeds of the wheels to determine the rolling circumferences. If a tyre deflates that circumference will change and so will the rotational speed. The TPWS doesn't know the tyre pressures, it just reacts to a change and it needs to be quite a significant change, approx 25% IIRC.

I didn't know that Peter, thanks.

[Jayw13702]

Are the tpms sensors corner specific?

Reason for asking is I’m at a tyre centre and want the rears put on the front, I’ve been told that it can’t be done as the tpms system will tell me incorrectly which wheel is punctured.

So by moving rear to front if a rear has a puncture the tpms system will tell me that it’s a front that faulty as the frequency that the sensor transmits cannot be changed!!!!

I thought that by resetting the tpms it will tell the computer which wheel has what frequency sensor


Sent from my Iphone using Tapatalk

[Britprius]

The 

2 hours ago, Jayw13702 said:

Are the tpms sensors corner specific?

Reason for asking is I’m at a tyre centre and want the rears put on the front, I’ve been told that it can’t be done as the tpms system will tell me incorrectly which wheel is punctured.

So by moving rear to front if a rear has a puncture the tpms system will tell me that it’s a front that faulty as the frequency that the sensor transmits cannot be changed!!!!

I thought that by resetting the tpms it will tell the computer which wheel has what frequency sensor


Sent from my iPhone using Tapatalk

No the sensors are not corner specific. However I marked each wheel on the inside with an indelible marker "1 to 4" in line with the list of monitors on Techstream. This enables me to go to a specific wheel if Techstream shows a problem such as a low monitor Battery.

If the car shows through it's own display which wheel has a problem "mine does not" this would affect the readings, but would then not allow tyre rotation to even out ware.

Lowering the pressure of one wheel at a time will show which monitor is in which wheel while being monitored in Techstream.

John.