Tyre Pressure Warning

BMJD · December 22, 2018

My 2014 IS300h F-Sport's low tyre pressure warning light has been coming on for the last 2-3 weeks. I have been checking the pressure in each tyre almost daily and nothing seems amiss so I suspect that the problem is with a sensor. Has anyone experienced this before and how can it be fixed?

Tyres are worn but well within limits, no obvious signs of damage.

NemesisUK · December 22, 2018

If you've checked the pressures, when cold and all is correct, the pressures are as suggested on the door pillar label, then I'd suggest resetting the TPMS using the button on the lower dash panel.

Hadrian · December 22, 2018

I've had a similar thing happen to me on a couple of occasions, when we've had some cold weather overnight. The TPMS is extremely

sensitive. My local service centre confirmed this, and said they'd had a lot of people call in, thinking they had a problem.

BMJD · December 22, 2018

The first time it happened this winter was actually the first frosty morning so I assumed that was the cause, but it hasn't sorted itself out since.

Last winter, it happened when there was a lot of snow but as soon as that cleared, it went away

Martin F · December 22, 2018

1 hour ago, NemesisUK said:

If you've checked the pressures, when cold and all is correct, the pressures are as suggested on the door pillar label, then I'd suggest resetting the TPMS using the button on the lower dash panel.

Yep, try this.

December 22, 2018

I've had a similar thing happen to me on a couple of occasions, when we've had some cold weather overnight. The TPMS is extremely
sensitive. My local service centre confirmed this, and said they'd had a lot of people call in, thinking they had a problem.

I blame schools

Sent from my BV5800 using Tapatalk

BMJD · December 24, 2018

Over the last few days it has been on and off sporadically. This morning for example, it was on then went off after 7 minutes; pretty much the same on the return journey. I went back out again shortly afterwards and it didn't come on at all. The weather hasn't been too cold or variable so I'm not convinced that this is the cause of it. As I understand it, a fault with a sensor or the system would mean that the light would be blinking - which hasn't happened. I'm starting to think it's on the mulled wine or something 😂

Martin F · December 24, 2018

Have you tried resetting the TPMS yet as suggested ?

If not you are just wasting peoples time if you choose to ignore suggestions.

BMJD · December 24, 2018

18 minutes ago, Martin F said:

Have you tried resetting the TPMS yet as suggested ?

If not you are just wasting peoples time if you choose to ignore suggestions.

Yes, several times, the problem keeps occurring.

NemesisUK · December 24, 2018

Did you follow the procedure as detailed in the handbook?

Time to stop guessing and get the car on Techstream and read off any error codes

Martin F · December 24, 2018

3 hours ago, BMJD said:

Yes, several times, the problem keeps occurring.

Ok, so maybe helpful if you let people know what you have and haven't tried in future.

Agree with Nemesis get somebody to take a look who can read the sensors. Can always pop into your local dealer and see if they will take a quick look for you.

BMJD · January 12, 2019

I checked the tyre pressure on Dec 26th, reset the tpms and the light has not come back on since then. I jacked the car up a few days after that and inspected the tyres to make sure that there wasn't a nail or something in one and all looked ok. It's a bit of a mystery.

Hadrian · January 22, 2019

Out of interest, I wonder if any of you have had the warning light come up recently, with the onset

of freezing temperatures ?

Dealkent · January 24, 2019

I thought it was just me , so pleased to see this discussion here , my tyre pressure warning light keeps coming on too . It often goes off after about 30 mins of driving , but other times doesn’t go off . Where is the button to adjust it ? .

NemesisUK · January 24, 2019

6 minutes ago, Dealkent said:

I thought it was just me , so pleased to see this discussion here , my tyre pressure warning light keeps coming on too . It often goes off after about 30 mins of driving , but other times doesn’t go off . Where is the button to adjust it ? .

On 12/22/2018 at 10:44 AM, NemesisUK said:

If you've checked the pressures, when cold and all is correct, the pressures are as suggested on the door pillar label, then I'd suggest resetting the TPMS using the button on the lower dash panel.

One doesn't adjust it one resets the trip point to the current tyre pressure, so make sure they are correct first.

olliesgrandad · January 24, 2019

12 minutes ago, Dealkent said:

I thought it was just me , so pleased to see this discussion here , my tyre pressure warning light keeps coming on too . It often goes off after about 30 mins of driving , but other times doesn’t go off . Where is the button to adjust it ? .

I had exactly the same issue with my IS300h. Spoke to the service manager at my local Dealer who said it is a cold weather thing and if the pressures were okay not to worry. Only happened in very cold weatgt.

Uti · January 24, 2019

You set your cold tyre pressure on existing temperature. The real temperature of tyres will change about 0,1 bar/10 celsius. So if you set tyre pressure when outside temperature is +20 celsius (cold tyres) the real temperature of tyres is 0,2 celsius lower when outside temperature is 0 (zero) celsius in the morning. I think that the pressure warning is alarming when tyre pressure is decreased about 0,3-0,4 celsius of adjusted temperature. If you dont`t want any false alarms, you have to be careful that every tyre is at the same temperature when you set your TPMS-system. If one tyre is in the sun and the other in the shadow there may be more than 0,2-0,4 diffenrence in the real pressure.

Uti

Hadrian · January 25, 2019

As others have said, On the IS300h the reset button is underneath the lower panel, more or less in line with the steering column, and a couple of inches back.

A mirror and torch will help in the first time of finding it. A shame they couldn't have made it a menu item, maybe they have in later models ?

Dealkent · January 25, 2019

5 hours ago, Hadrian said:

As others have said, On the IS300h the reset button is underneath the lower panel, more or less in line with the steering column, and a couple of inches back.

A mirror and torch will help in the first time of finding it. A shame they couldn't have made it a menu item, maybe they have in later models ?

Just put pressure in all the tyres , all the same now , but the bloody light is still on ! looked in owners manual and picture shows a reset button but I could not see it !! After reading you’re post I will now go and have another look it must be very well concealed ??!!

Dealkent · January 25, 2019

This is very annoying now , eventually found the very well hidden reset button , followed instructions in the manual , it goes off , but then comes back on again . It’s 11 degrees out there today , it’s not really an excuse for these sensors to be over sensitive. I am now hopin* it just sorts itself out , next time I’m near the dealer, which isn’t often , I will go in and see If anyone can help ..

wharfhouse · January 25, 2019

1 hour ago, Dealkent said:

This is very annoying now , eventually found the very well hidden reset button , followed instructions in the manual , it goes off , but then comes back on again . It’s 11 degrees out there today , it’s not really an excuse for these sensors to be over sensitive. I am now hopin* it just sorts itself out , next time I’m near the dealer, which isn’t often , I will go in and see If anyone can help ..

In my experience there is little to no need to have to mess around with the TPMS - I have only had it come on once in over two years when I had one tyre that was down on pressure, just after I bought the car from the dealer, so it worked correctly. I made sure all the tyres were the same temperature (so not in sun/shade etc.) and set all the pressures to 36psi as per the handbook and the TPMS light went out and has stayed out ever since (I did not do any TPMS reset) - the tyre was OK - just a bit down on pressure. I do check my tyre pressures every few months and in particular make sure I add some air as temperatures drop in winter to maintain the cold pressure at 36psi - also all tyres lose some pressure over time so do need checking every few months if you want to maintain them within a sensible pressure tolerance. I also check tyre pressures after a dealer/garage service and interestingly have twice found that one tyre (same position each time) was low on pressure after a service (the other three being correct) - could be wrong but I think they have a different machine for each corner of the car at dealers and so I guess one was not working correctly. If the TPMS has been reset and is now not working correctly I would carefully go through the process again - so get the tyres stone cold (leave overnight) and make sure all are the same temperature (so not one in sun and one in shade etc.) and then set pressures correctly using a good handheld pressure gauge (the ones in the pumps are notoriously poor) and finally reset the TPMS (using the reset switch as below) to register the correct pressure. From then on it really should not indicate any problem unless one or more tyres really have lost a reasonable amount of pressure. If it is coming on, with air temperature changes we get in the UK which are not that extreme, then given my experience (of not having any issues) sounds like it could be a fault in the TPMS/sensors.

■ How to initialize the tire pressure warning system
Park the vehicle in a safe place and turn the power switch off.
Initialization cannot be performed while the vehicle is moving.
Adjust the tire inflation pressure to the specified cold tire inflation pressure
level. (→P. 568)
Make sure to adjust the tire pressure to the specified cold tire inflation pressure
level. The tire pressure warning system will operate based on this pressure level.
Turn the power switch to ON mode.
Press and hold the tire pressure
warning reset switch until the tire
pressure warning light blinks
slowly 3 times.
Wait for a few minutes with the power switch in ON mode and then turn
the power switch off.

Dealkent · January 27, 2019

When I checked the required pressure for tyres it says 25 ! , where are you get 36 from ? . I used air pressure machine in petrol station which you set digitally which then automatically goes to the set pressure. I will have another look at the manual and check the correct pressure. How can something so simple become so complicated?!

wharfhouse · January 27, 2019

36 psi all around (that's 2.5 bar - hope you weren't setting them at 25 psi as that is very low) for 17" wheels - not sure about other sizes. I would never rely on a forecourt pressure gauge - notoriously badly calibrated and tyres will be warm to some degree when you get there. I have an electric tyre pump (plugs into the car) and decent (digital) handheld pressure gauge. After leaving tyres to be stone cold (usually overnight) and all at the same temperature, I pump tyres up with the electric pump - usually a few psi over the stated pressure and then check with the hand held pressure gauge (which is more accurate than the one on the pump) and let them down to the correct psi. I do this every few months (only takes around 15 minutes for all 4 wheels) and never had a problem with the Lexus TPMS or the tyre monitoring on previous BMWs.