Tyre pressure warning light.

Hadrian · August 8, 2018

Today I had the Tyre pressure warning light come up.

I checked all tyres and pressures seemed ok, although I did put a bit more air in just to make sure.

The light is still showing though, how do I reset it ? Most of the articles I see, talk of holding in the TPMS button, which my car doesn't have, AFAIK.

It flashes once when the ignition is turned on.

Maybe it's down to the weather ?

ianhu · August 8, 2018

If you have an is300h the button is on the steering column. About a foot down from the wheel.

I think the button has to be pressed after engine off turn to IGN then hold button for about 3 to 5 seconds.

I've had tpms issues had to fix with techstream though to add new sensor.

Good luck

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Andrew888 · August 8, 2018

For the life of me I cannot see it on mine (TPMS Reset) (2016 MY)

Hadrian · August 8, 2018

Thanks for the reply. The problem is, there are so many versions of the is300h.

I went over the road to the Lexus service centre and a chap kindly came out and showed me where the button is..

It is more or less where you said, but very difficult to see. you would need a mirror in the footwell to be able to see it.

he said it's very common for the light to come on, as they are so sensitive. A lot of people just leave the light on, which

is ok until you get a puncture.

matt8 · August 8, 2018

You have to be on your knees outside the car to see the switch. It runs almost parallel to the floor.

NemesisUK · August 8, 2018

One only needs the reset button if one changes the benchmark pressure i.e. increasing pressures for full load conditions.

Hadrian · August 8, 2018

1 hour ago, NemesisUK said:

One only needs the reset button if one changes the benchmark pressure i.e. increasing pressures for full load conditions.

It can activate for a number of reasons, temperature changes being just one.

NemesisUK · August 8, 2018

1 hour ago, Hadrian said:

It can activate for a number of reasons, temperature changes being just one.

Indeed, check tyre pressure cold is a must.

Not had an issue with over-pressure, when temps drop winter time I always adjust.

I wonder what the tolerance is on the warning?

ianhu · August 8, 2018

That's very true.

I was resetting mine with techstream and for a day or so the tpms would not illuminate when the car was running. Until day 2 then it would flash for a few minutes and stay lit constantly. This would go on until I next reset it. Then the same repetition would start again. I got the suspect faulty sensor changed. And the garage told me the car will learn about the new sensor. Tripe. A week later still hadn't changed the behaviour.

Perhaps on some cars that might be the case and works!? I don't know. Certainly my car wasn't learning any such thing.

Out came techstream and I inputted all sensor id 's into techstream wizard, it finally accepted all and the new tpms ID values and since then no issues.

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Hadrian · August 9, 2018

9 hours ago, NemesisUK said:

I wonder what the tolerance is on the warning?

Not a lot apparently. The chap who sorted mine out, says it's a very common issue.

Just a shame there's nothing (I could find) in the users manual. I shall print something out for the benefit of the next owner.

Hadrian · August 9, 2018

8 hours ago, ianhu said:

That's very true.

I was resetting mine with techstream and for a day or so the tpms would not illuminate when the car was running. Until day 2 then it would flash for a few minutes and stay lit constantly. This would go on until I next reset it. Then the same repetition would start again. I got the suspect faulty sensor changed. And the garage told me the car will learn about the new sensor. Tripe. A week later still hadn't changed the behaviour.

How do you tell which sensor is giving the warning ?

NemesisUK · August 9, 2018

Tyre pressures are displayed in the cluster, scroll through the options

ianhu · August 9, 2018

They don't display in the cluster on my 2014 is300h, and I don't think anything is in the manual about displaying the individual pressures,. Just the warning light. I think displaying the pressures on the cluster came in more recent models. Although I would like to hear the same from someone who has the exact same model and year as mine.

Anyway, a guy at the tyre place had to check each wheel by holding a close proximity tpms tool. One didnt read and the other 3 did.

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rayaans · August 9, 2018

4 hours ago, Hadrian said:

How do you tell which sensor is giving the warning ?

On the IS you don't.

It's just a case of warning you that the pressure is low so you need to check all 4 tyres. Could be more than one that is low.

Hadrian · August 9, 2018

Thanks, I thought that was probably the case.

I didn't realize that all vehicles have to be fitted with TPMS now.

ianhu · August 9, 2018

Bloody lexus..... They gave the individual pressures in the cluster to more recent buyers of the same car.

Little things like that bug me.

My car came with no sat nav. They reckon it couldn't be added afterwards. Guess what... It can and was (by me) , small ecu update made it all work OEM style.

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rayaans · August 9, 2018

5 hours ago, ianhu said:

Bloody lexus..... They gave the individual pressures in the cluster to more recent buyers of the same car.

Little things like that bug me.

My car came with no sat nav. They reckon it couldn't be added afterwards. Guess what... It can and was (by me) , small ecu update made it all work OEM style.

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Did they? Because I don't think the facelift has individual tyre pressures available.

You can add sat nav to any Lexus. Most dealers aren't prepared to do this so will just say it can't be done. Makes sense to me though, just get a car with a better spec.

ianhu · August 9, 2018

I got this car roughly 3k cheaper because it was repossessed by finance company from the previous owner. Then £250 for the second hand nav unit.

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Hadrian · August 9, 2018

14 hours ago, NemesisUK said:

Indeed, check tyre pressure cold is a must.

Yes, I've just found that out. Today is a lot cooler than yesterday, and the warning came back on. At least I know

how to cancel it now. 🙂 I assume when you cancel the light, that resets the pressure limits. ?

I'm not sure what the pressures should be on mine, with Dunlop sports fitted. I can't make head nor tail of the figures on the door pillar.

I have them at about 34 psi at the moment.

rayaans · August 9, 2018

Pretty sure they should be 36psi. Reset after filling up otherwise it won't give a warning as soon.

Then just leave it. You don't need to keep resetting every time you top up

NemesisUK · August 9, 2018

58 minutes ago, Hadrian said:

At least I know how to cancel it now. 🙂 I assume when you cancel the light, that resets the pressure limits. ?

One can cancel the light by increasing the tyre pressure to above the set pressure. Each time one 'cancels' the warning by using the button one initialises the the system and the current tyre pressures are used as the new benchmark, whether they are correct or not.

Hadrian · August 9, 2018

57 minutes ago, NemesisUK said:

Each time one 'cancels' the warning by using the button one initialises the the system and the current tyre pressures are used as the new benchmark, whether they are correct or not.

Yes I imagined that was probably the case...........I'll go up to 36psi now

Thanks all.

Has · June 19, 2020

The problem starts once you reset the TPMS by pressing the button under the steering column. Most do this after a puncture repair. The trick is to lower the pressure in all 4 tyres to 26psi, reset the TPMS by pressing the button. After 3 flashes of the illuminated icon, release the button. Now inflate all 4 tyres to the recommended 36psi. That should now stop the TPMS warning light from coming on.

ColinBarber · June 20, 2020

12 hours ago, Has said:

The problem starts once you reset the TPMS by pressing the button under the steering column. Most do this after a puncture repair. The trick is to lower the pressure in all 4 tyres to 26psi, reset the TPMS by pressing the button. After 3 flashes of the illuminated icon, release the button. Now inflate all 4 tyres to the recommended 36psi. That should now stop the TPMS warning light from coming on.

By doing that you are only going to get a warning if a pressure dropped to something like 22 psi. That is far from ideal.

Has · August 8, 2020

I have had this recurrent problem of the TPMS warning light coming on. I had used a home tyre inflator which was faulty. The tyres inflated to 36psi pressure were in reality only 28psi! So I had relied on my domestic inflator and should have been more vigilant. Mea Culpa!