Powdered Toast Man Posted December 7, 2011 Report Share Posted December 7, 2011 The other day I got a tire pressure warning for my left front. It was a bit low (probably due to the cold weather) so I took it over to the gas station and topped up all the tires. Well, the TPMS warning for that wheel will not go away! The pressure reading is the same as the other 3 tires, so it's not low anymore. I checked the owners manual and it says that the vehicle may have to be driven for 20 minutes before the warning disappears. Well, did that, and it's still there. Any suggestions? Quote Link to comment Share on other sites More sharing options...
19InBlkJrny Posted December 7, 2011 Report Share Posted December 7, 2011 Could be a bad sensor. If under warranty, I would see if the dealer will do a "redress", meaning change out the gromets and seals. Other than that I'm stumped. Hope you get that handled soon. Omar Quote Link to comment Share on other sites More sharing options...
drb227 Posted December 7, 2011 Report Share Posted December 7, 2011 The other day I got a tire pressure warning for my left front. It was a bit low (probably due to the cold weather) so I took it over to the gas station and topped up all the tires. Well, the TPMS warning for that wheel will not go away! The pressure reading is the same as the other 3 tires, so it's not low anymore. I checked the owners manual and it says that the vehicle may have to be driven for 20 minutes before the warning disappears. Well, did that, and it's still there. Any suggestions? I recently had a nail in one of my tires that was causing a slow leak. I got the low tire pressure warning twice and each time I had to ensure that the tire was filled back to 36 psi before the warning would clear. It seems that the warning will not clear until you bring the tire fully back to what the pressure should be. I filled it once to 35 psi to match the other tires at the time and that was not enough to clear the warning. It wasn't until I got all tires back to 36 psi that the warning finally cleared. Quote Link to comment Share on other sites More sharing options...
Powdered Toast Man Posted December 7, 2011 Author Report Share Posted December 7, 2011 I recently had a nail in one of my tires that was causing a slow leak. I got the low tire pressure warning twice and each time I had to ensure that the tire was filled back to 36 psi before the warning would clear. It seems that the warning will not clear until you bring the tire fully back to what the pressure should be. I filled it once to 35 psi to match the other tires at the time and that was not enough to clear the warning. It wasn't until I got all tires back to 36 psi that the warning finally cleared. Aaah, maybe that's it. I think I got it up to 34 or so. It's difficult to gauge in winter because the temperatures keep swinging from below -20 to around -5ºC. I'll try inflating it some more and see if that clears the warning. Quote Link to comment Share on other sites More sharing options...
ChrisPollard Posted December 8, 2011 Report Share Posted December 8, 2011 Scary - I had the same thing on Monday night - left front tire. Stupid thing keeps going off every startup, even though all the pressures are the same. I'm having the same temperature problem as you ... it was -25 Monday night, today it's -6. Tomorrow is supposed to be about -14. Really hard to keep consistent pressures when the outside temperature is the variable affecting the TPMS readings! Too bad they couldn't put a temperature sensor in those things too - so it would self-adjust for outdoor conditions! Hmmm ... maybe I can patent that idea for a new generation of TPMS sensors.... nerner 1 Quote Link to comment Share on other sites More sharing options...
bramfrank Posted December 8, 2011 Report Share Posted December 8, 2011 Temperature compensation IS a feature in some sensors - I have that feature on one of my motorcycles. But then again, since the vehicle knows the outside temperature, any correction could be applied in the vehicle, rather than at the sensor. Even then, tire pressure is an absolute. You are supposed to have 36 pound presure when the tire is cold (i.e. in the morning). Simple enough to do if you own a compressor and have a good tire pressure gauge. Quote Link to comment Share on other sites More sharing options...
ChrisPollard Posted December 8, 2011 Report Share Posted December 8, 2011 But if you put 36psi in at -25 - then it warms up to -5 by the afternoon, you've had 20 degrees of temperature shift. That's 36 degrees Fahrenheit for our American friends. At 1psi change for every 10*F, that's a 3.6PSI shift (let's call it 4) - now your tire pressure is a "cold" 40psi before you head home from work! So if you were 'proper' and deflated at -5 to 36psi, when the temps drop back to -25 overnight, you will now be at 32psi cold in the morning. I don't know about you, but I'm not all in favour of inflating and deflating all four tires every time I get in and out of the vehicle as the temps change through the day just to keep the ol' TPMS happy. It should just be quiet if all of the tires are the same pressure and only set off lights and alarms if one tire is horribly out of whack with the rest. Or at least be smart enough to notice that hey, all four tires are now the same pressure again ... must be okay. Showing warnings for no GOOD reason is a fast track to me opting to simply ignore the dang thing. Quote Link to comment Share on other sites More sharing options...
BUGS Posted December 9, 2011 Report Share Posted December 9, 2011 Put nitrogen in the tires and no more temperature related fluctuations. Quote Link to comment Share on other sites More sharing options...
ChrisPollard Posted December 9, 2011 Report Share Posted December 9, 2011 It IS nitrogen in the tires from the factory. That's what the little green caps on the valve stems are to indicate. Not sure who told you nitrogen wouldn't fluctuate with temperature, but they lied. From "getnitrogen.org" ... What are the effects of temperature change on my nitrogen filled tires? The pressure in nitrogen filled tires will change when the temperature changes, just as it does with air filled tires, because nitrogen and oxygen respond to changes in ambient temperature in a similar manner. For example, when your vehicle is parked it will lose a similar amount of pressure for every 10 degree change in temperature, whether the tires are filled with nitrogen or air. The calculations for this change are based on the Ideal Gas Law. A good rule of thumb is this: For every 10 F degree change in temperature, the pressure will change by 1.9%. If a tire is filled to 32 psi at a temperature of 75 F degrees and the temperature drops 10 degrees, the tire pressure will drop to 31.4 psi; a difference of .6 psi. If a 100 psi tire is filled at 75 F degrees and the temperature drops 10 degrees, the tire pressure will drop to 98.1 psi; a difference of .9 psi. These fluctuations will occur as the temperature rises and falls no matter what the inflation gas. Fortunately, tire manufacturers are well aware of these conditions and design their tires and recommend their cold inflation pressure accordingly. However, nitrogen does not contain the moisture and other contaminants found in compressed air so, as you drive and the tires heat up, nitrogen filled tires will fluctuate less in temperature and pressure than air filled tires while driving. The bottom line is, you will still see pressure changes with nitrogen but, overall, your tires will run cooler and at a more consistent pressure than if they were filled with air. For more information please see the Effects of Temperature on Pressure which shows the expansion rates of dry air or nitrogen, in both a truck and passenger tire, as the temperature increases. It also shows how the vapor pressure of water increases as temperature increases and includes a brief explanation. Quote Link to comment Share on other sites More sharing options...
bramfrank Posted December 9, 2011 Report Share Posted December 9, 2011 Put nitrogen in the tires and no more temperature related fluctuations. I guiess you weren't paying attention when they discussed Boyle's law in high school? Quote Link to comment Share on other sites More sharing options...
Powdered Toast Man Posted December 9, 2011 Author Report Share Posted December 9, 2011 Yeah, I had the nitrogen filled tires and have fluctuations as usual. Anyway, I got the tire over 36 psi and it shut up. For the record, it doesn't give you a warning until the tire gets below a threshold pressure. However, to CLEAR the warning, you have to get it back over 36psi. Which is also kind of irritating because the metric TPMS readout is in KPA, not psi. Quote Link to comment Share on other sites More sharing options...
bigtsr Posted December 9, 2011 Report Share Posted December 9, 2011 "Which is also kind of irritating because the metric TPMS readout is in KPA, not psi." I haven't tried it but it appears at least on the 4.3 that you can change the read outs from metric to US. I checked with my dealership and they don't even have nitrogen availiable on site. Quote Link to comment Share on other sites More sharing options...
bramfrank Posted December 9, 2011 Report Share Posted December 9, 2011 Yeah, I had the nitrogen filled tires and have fluctuations as usual. Anyway, I got the tire over 36 psi and it shut up. For the record, it doesn't give you a warning until the tire gets below a threshold pressure. However, to CLEAR the warning, you have to get it back over 36psi. Which is also kind of irritating because the metric TPMS readout is in KPA, not psi. OK, so to help those who don't have a pencil and paper or access to the Internet or can't be bothered figure out what it is, 36 psi is slightly more than 248 kpa Quote Link to comment Share on other sites More sharing options...
ChrisPollard Posted December 9, 2011 Report Share Posted December 9, 2011 36 PSI shows as 250kPa on the EVIC, but still - I don't know ANYBODY, ANYWHERE that inflates tires to kPa. Even tire shops. And yes, you can roll through menus and change it to show PSI - but then it switches your odometer to miles, your speed to mph, and your L/100km to mpg. It would be nice if you could just push the right arrow on the wheel and flip between kPa and PSI like you can with km/h and mph under the speed display. Quote Link to comment Share on other sites More sharing options...
Powdered Toast Man Posted December 10, 2011 Author Report Share Posted December 10, 2011 36 PSI shows as 250kPa on the EVIC, but still - I don't know ANYBODY, ANYWHERE that inflates tires to kPa. Even tire shops. And yes, you can roll through menus and change it to show PSI - but then it switches your odometer to miles, your speed to mph, and your L/100km to mpg. It would be nice if you could just push the right arrow on the wheel and flip between kPa and PSI like you can with km/h and mph under the speed display. AGREED. Even the sticker on the side of the door has the recommended pressure in PSi. Quote Link to comment Share on other sites More sharing options...
bramfrank Posted December 10, 2011 Report Share Posted December 10, 2011 That isn;t how my EVIC works . . . . mine displays pressure in kpa and switching to US measure only affects the digital readout for the speedometer.display - nothing else is affacted. My TPMS displays in approximately 1 pound increments . . . 241, 248, then 265 kpa. I MUCH prefer the way the 300 worked, displaying in 1 kpa increments or in PSI - and the printed manual says that I shouldn;t be displaying pressure at all, but simply have an alert light - and the description of the 'premium' TPS shows a dot matrix readout that doesn;t match the vehicle either - then again it also says that Bluetooth is standard equipment. Quote Link to comment Share on other sites More sharing options...
bigtsr Posted December 10, 2011 Report Share Posted December 10, 2011 "That isn;t how my EVIC works . . . . mine displays pressure in kpa and switching to US measure only affects the digital readout for the speedometer.display - nothing else is affacted." Yes same as mine when using steering wheel controls but mine changes everything using the radio screen menus. My door sticker for the tires shows both KPA an LBS for desired pressures. Quote Link to comment Share on other sites More sharing options...
ChrisPollard Posted December 11, 2011 Report Share Posted December 11, 2011 Maybe the lockpick folks can make a mod for the 4.3's to allow an easy right arrow flip between PSI and kPa. That would almost be worth the hack in my world! Quote Link to comment Share on other sites More sharing options...
Cableguy Posted January 13, 2012 Report Share Posted January 13, 2012 I have a 2010 sxt with the 3.5 v-6 and 17 inch wheels at P225/65R17. I ended up bying some 16in steel wheel with some Hercules avalanche extreme tires at p225-70R16 for winter tires. The door panel says 32psi but I'm running my winter tires at 34psi at -10degrees C. I don't have the sensors so my TPMS light is on but I told my wife a black piece of electrical tape can get rid of the light. LOL! I'm not having any issues with traction. Quote Link to comment Share on other sites More sharing options...
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