TPMS problem - yet again

[johnatg]

This morning my tyre pressure warning light came on as soon as I started the car. On checking the display, one of the pressure readings was illuminated in yellow, although it was still transmitting pressure. The pressures were quite low, but I put that down to the low temperature (-6 deg). As I drove the tyre warmed up a bit and the pressures rose - even the one showing a problem.

Does this mean that the sensor in that wheel has a low Battery? I guess I'll need to get all 4 replaced - the car is 8 years old today. I understand that the batteries can be replaced with a fit of a fiddle - maybe I should get 4 new sensors but keep the old ones with a view to fitting new batteries.

Any recommendations, preferably avoiding Lexus dealers?

Apologies for the blurry photo - it was long exposure on night vision.

 

[NemesisUK]

Or does it just mean you need to up the cold pressures to account for the low ambient temps of winter? I always have to top up the pressures in the winter, then drop them again come the milder months..

[F.A.]

Same happened in our GSF. The warning light turned off when the flagged up tyre got to 2.3 Bar. I increased the pressure and it solved the problem, so  @NemesisUKexplanation is spot on. 
 

 

[LenT]

2 hours ago, johnatg said:

This morning my tyre pressure warning light came on as soon as I started the car. On checking the display, one of the pressure readings was illuminated in yellow, although it was still transmitting pressure. The pressures were quite low, but I put that down to the low temperature (-6 deg). As I drove the tyre warmed up a bit and the pressures rose - even the one showing a problem.

Does this mean that the sensor in that wheel has a low battery? I guess I'll need to get all 4 replaced - the car is 8 years old today. I understand that the batteries can be replaced with a fit of a fiddle - maybe I should get 4 new sensors but keep the old ones with a view to fitting new batteries.

Any recommendations, preferably avoiding Lexus dealers?

I had to top up all four tyres today - and all by the same amount - due to minus ambient temperatures.  So I think Peter’s right.  You should check the Manual to see if your TPMS provides a low Battery warning - I don’t think mine does.

As for Battery replacement, it can be done but I for one wouldn’t contemplate it.  After all, you’ve still got to get the tyre off in the first instance to get at the valve.  In terms of age, you could well be in that area, but mileage (ie the total time the TPMS has been active) is also a factor.

Presuming that you have now inflated the tyres to the correct pressures, then you could try resetting the TPMS and see if that eliminates any warning lights.  If it doesn’t, then at least you know the pressures are correct.

What are your tyres like?  If you were contemplating fitting a new set, then I would be inclined to replace the TPMS valves at the same time, as you’re having to remove the tyres anyway.

When I had to replace a TPMS valve, a large local tyre retailer was able to supply and fit a compatible unit for £65.  If you tie a new valve set in with the new tyres, you can probably negotiate a deal.  But it can’t hurt to put the same proposition to your local Lexus dealer.  You may be surprised!

[DavidCM]

My Tpms has been playing up on the last 2(freezing)days as well.I know that temperature has an effect on tyre pressure and once they warm up,either in sunlight or warmth from friction or brake discs,the warning light disappears.

I think it would be wise,as Peter says,to increase the pressures for a while

[johnatg]

Thanks, chaps. A bit of air solved the problem.

Interesting that another one or more tyres can show the same low pressure but only one is flagged up on the display.

[NemesisUK]

8 minutes ago, johnatg said:

Thanks, chaps. A bit of air solved the problem.

Interesting that another one or more tyres can show the same low pressure but only one is flagged up on the display.

Probably down to 'rounding up/down' as the display only shows integers 

[F.A.]

1 hour ago, NemesisUK said:

Probably down to 'rounding up/down' as the display only shows integers 

Yes, I noticed that the remaining three tyres changed from 2.2 bar to 2.3 bar a while before the tyre with the warning light did.