XF and XFR ( X250 ) 2007 - 2015

Freak'n TPS

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Old 12-11-2018, 08:38 AM
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Default Freak'n TPS

So my TPS warning lights came on this morning and freaked out. Turns out it was cold this morning and my tire pressure slipped down to 30PSI and the TPS thought that was a problem. Stopped and put 4 PSI in all wheels and the lights went out, but now my tires will be over pressurized when they warm up.

Who ever thought that the TPS was a good idea...
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Old 12-11-2018, 09:15 AM
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Was adopted early on in Europe, no surprise there but here in the US it was Federally mandated following the Firestone Tire disaster that caused hundreds of deaths due to under inflated tires.

Anyhoo, I'm guessing your question was rhetorical.

34 psi cold shouldn't result in tires exceeding their maximum recommended pressure when heated. What size wheels?

 
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Old 12-12-2018, 09:36 AM
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Don't shoot the messenger.

If it's cold and your tires are below specs, then you need to put air. Why would it ever be bad that the car is telling you that you have a real problem?

If it heats up and now you are above specs, you need to let air out.

Don't you just hate the real world?
 
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Old 12-13-2018, 08:07 AM
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>Don't you just hate the real world?

But come on 30PSI and the light comes on?? That's a little bit over intrusive if you ask me. But now I know.

The interesting thing is, the signal came from the wheel that was a problem when I bought the car last January. When I test drove it, the warning light was on. Between the test drive and purchase inspection that tire failed to hold air so they replaced the valve/sensor. I took the car home and the next morning (New Years Day...) the tire was flat. AAA came to help me change and we found the donut spare down to ~30PSI... =:-0. They pumped it up, I brought the car back to the dealer the next day and they began looking at things.

Turns out, in prep'ing the car for sale they replaced all the tires... But one turned out to be bad, so the replaced that new tire with a fresh new tire and everything was good.

Until the light came on for that wheel this week.

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Old 12-13-2018, 12:21 PM
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i have a dent in the rim and air escapes in the cold weather. every 2 weeks i get the low pressure warning. bought an easy pump for $20 at autozone and im good to go
 
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Old 12-13-2018, 06:59 PM
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It's pretty normal to add a few psi of air once the winter sets in and the temp drops (brining down tire pressure) and release a few in the spring. That way you are usually in the right range.
 
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Old 12-14-2018, 07:51 AM
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>It's pretty normal to add a few psi of air once the winter sets in and the temp drops
Ya, thanks, understand that
But what surprised me was that it signaled with a reading of 30psi in the tire. That seemed quite over-sensitive to me.
Now I know
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Old 12-14-2018, 09:55 AM
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Most of our cars call for 36psi on the door placard. 30psi is over 15% low, and TPMS certainly SHOULD be warning you at that point. Also, that 36psi spec is cold pressure. If you check in the summer at 95 degrees or especially if after driving even a short distance the reading should be 38 or 40.
 
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