Yet Another Tpms Question!

[rayaans]

So the TPMS light has come on today - wife nearly soiled her panties! She thought she had a puncture or something.

Anyways - visually, the tyres look like they have a decent amount of pressure at the moment so will check in a few days.

BUT - do you have to reset this thing using the button under the steering wheel? Or does it disappear by itself?

Reason being, the manual is somewhat contradictory. It says it should go away on its own after a few minutes, but then also goes on to talk about initialization (resetting basically).

I guess I could reset it after filling to 36 psi but how do you this exactly? Im assuming its just turn the car fully on (foot on brake + power button) and then press and hold the reset switch until it flashes 3 times?

The worst part of this light is the fact that Im away until Friday night starting early tomorrow morning AND my wife is going to bug me about it on the phone every day until its sorted :/

[ColinBarber]

I would set the pressures to your liking and then do a system reset so that your pressures are set as the midpoint.

Yes with the ignition on, ideally in 'Ready', you press and hold until it flashes. You should then leave it switched on for a few minutes for the next polling to take place.

[Tel]

See previous Posts to resolve the issue!

Tel

[DJP]

I would set the pressures to your liking and then do a system reset so that your pressures are set as the midpoint.

Yes with the ignition on, ideally in 'Ready', you press and hold until it flashes. You should then leave it switched on for a few minutes for the next polling to take place.

Keep pressing the button until the light flashes 3 times, then release. Mine's just come on with only 500 miles on the NX clock. Think I may have a slow puncture already!

[rayaans]

OK so my wife got impatient - called me to say that the light was on in the afternoon and still on after a 10 minute drive so she went and put some air in.

Air readings were OK but as expected were relatively low for the car - 32,33,33,35.

She pumped them up to 37psi all 4 and it went by itself (no reset required) after 2 minutes or so.

[DJP]

Very industrious of her! I think you may well find the light will come back on again until you follow the reset procedure.

Sent from my iPad using Lexus OC

[rayaans]

Very industrious of her! I think you may well find the light will come back on again until you follow the reset procedure.

Sent from my iPad using Lexus OC

Ill have to see if it comes back on.

However, the manual states that the light SHOULD go off by itself after filling up with air. It also says the reset procedure should only be used when rotating tyres, going on long journeys etc. Nothing about routine air filling or when pressure drops due to natural temperature drops.

[ColinBarber]

The light should go out when you pump them up but the system may have been reset previously with the pressures at 40 psi or higher which means you are only just above the threshold for triggering the alarm again. Resetting the system when the tyres are set at your desired pressure will give you less false alarms.

[rayaans]

The light should go out when you pump them up but the system may have been reset previously with the pressures at 40 psi or higher which means you are only just above the threshold for triggering the alarm again. Resetting the system when the tyres are set at your desired pressure will give you less false alarms.

Thats what I fear - false alarms!

However, because I was bored, I phoned the dealer as to how it all works. They said that 4psi below what it should be and the light will turn on and it depends on the lowest tyre.

So, it was set to 36psi a month ago when the car was bought from the dealer. Lowest tyre was at 32psi so it was triggered. Pumping back up to 37psi will get rid of the light.

The dealer confirmed that you shouldn't ever need to reset the tpms unless you are of course rotating tyres etc

[DJP]

The manual disagrees with what your dealer says. As Colin posted above, initialising the system will prevent false alarms as the benchmark is reset to the new pressures.

[rayaans]

The manual disagrees with what your dealer says. As Colin posted above, initialising the system will prevent false alarms as the benchmark is reset to the new pressures.

Id assume its initialised at 36psi though so having 37psi is not going to make any difference really to when the light comes on or not.

36psi is recommended so surely the tpms should be left at 36psi? That way you know when you're below it. If I changed it to 37psi the light would come on at 33psi so that'll be more of a hassle as I don't think 33psi is actually that low for the car.

[Bob99]

With all the technology in the car it would have been good to have a display of the pressure for each tyre. This would show up a possible puncture which everyone worrys about or just normal leakage and / or cold temperatures. Mine came on when I was about to travel home a couple of weeks ago late at night, tyres looked OK and after a few miles it went off, the next day I checked them all and just reinflated to 36 psi as they were all around 32.

[DJP]

I agree a tyre specific reading would be better, especially with the lower profile tyres. My NX has 600 miles on the clock and I've a slow puncture (or leaking valve) but it's pretty easy to see. Hopefully just a puncture to have repaired this afternoon.