# Low pressure tire sensor problem



## Beckman (Oct 3, 2005)

Hey guys,

My low tire pressure warning light came on out of the blue this morning.

I immediately pulled over and inspected the tires. I didn't put a guage to any of them, but they all looked fine. 

The last time this happened was when I had just purchased it from the dealer. I suspect they let a lot of air out of the tires for a softer ride.

Anyway, last night was our first freeze. I wondered if that could have anything to do with it. It was warm by lunch, went out for a drive, and no change.

Anyone have any ideas? Do things things go bad l lot? How hard are they to diagnose and replace?

Thanks, Beck


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## aslondon (Nov 3, 2007)

Happened to me the other day - out of the blue. It was right after the temp had dropped into the 40's. I let the truck sit for 4 hours and check it, sure enought 2 tires were at 28lbs and 2 were at 30lbs. Damn thing worked just fine. I aired them up to 35lbs (factory spec). BTW the light does not go out until you start driving for a short distance (maybe a mile or two).


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## Z_Rated (Apr 29, 2006)

Common issue with this system. As for what it is, I'm not certain, but it seems to be temperature related. Other possible variables include elevation and electro/RF interference. Suggest getting a tire gauge and keeping it in the truck with you so you can be sure. 

My feeling is the system is nice to have, but should not replace the fact that you should still keep an eye on things yourself. The system has its bugs, but has never failed when low as far as mine goes.

Anymore questions, just ask. Z


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## azrocketman (Oct 5, 2005)

Basic physics guys. If the volume stays the same and the temperature decreases then the pressure goes down. The opposite is true; if the volume stays the same and the temperature increases then the pressure goes up. Set the tires to the factory specification or do a science project to see where the system triggers.

Steve


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## Z_Rated (Apr 29, 2006)

azrocketman, very true, but the issue is even if the pressures stay above the stated trigger value the system has been known to go off. I have heard of increasing the pressures to help the situation, but that usually means to air up above the factory specification. 

As for testing, my own system triggers as stated in my manual at 28psi. On the occasions that my TPMS has faulted all tires were close to specification with the factory BFG Rugged Trail tires. In the valley it works well, but at 4000' and above I get faults near power lines at various temps with normal pressures.

Overall the system works for me, Z


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## drexel18 (Nov 15, 2007)

Same thing happened on my 07 Frontier CC on our first real cold morning. Checked all four tires with air gauge and they were all 31 psi cold. Dealer checked and set to 36 psi and light is now out. I know a cold tire pressure will increase as the tire heats up. Just can not figure out how 4 tires could all lose 5 psi each in 4,000 miles since I bought the truck new in August...


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## spidey (Apr 3, 2007)

Happened to me when winter hit to. Checked my tires on the Sunday in my garage and they tested fine. WEnt out Monday morning and it went off. Was because the pressure dropped becausae the temp was about -35 outside. Aired up and it never came back the entire winter.

But the following fall it happened agaian because of the cold


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