TPMS

Got a quick question. On my 21 tacoma SR my two front tires are consistently showing 31 PSI through the toyota ap it never changes. The rears will go up and down usually a pound depending on heat and if ive driven and the tires are warm or cold. On my 3 tire gauges they are at 35 pounds. I trust the gauges more than the ap for that but if something was wrong with the TPMS system I would like to get it checked out and fixed if its broken. Is that even covered by the warranty. (Aprox 8000 miles and bought in December 2020) BTW it is an SR so the tire pressures don't show on the information screen by the speedometer. All i have is a little tire light that lights up when low but it hasn't lit up. Thanks for any help

 

The TPMS is always off a few psi and sometimes takes a while to update the systems. I would probably just put the phone down and drive the truck until the light comes on from an issue. I don't even have TPMS on my tires anymore.

 

Just checking, you hit the TPMS set button under the dash after inflating? Not sure if the SR has that.

 

Yes I tried that but didn't fix it. Like my mechanic dad used to say, don't rely on your phone to tell you there is a problem with your car. The car will tell you (strange noises, smells, not performing right) and it's my job to do routine checks on fluids and air pressure for the tires and not wait for an ap to tell me

 

Trust the air gauge. If the gauges show 35 PSI rear and 31 front I'd add some air to the front and drive it, I like about 35 PSI all around. The purpose of the warning light is to inform you of a sudden loss of air pressure while driving. Lots of people bitch about having TPMS at all. My 07 Tacoma is the 1st vehicle I've owned with the feature, all 3 vehicles in the driveway have it now.

Twice since having a vehicle with TPMS the warning light came on while driving indicating I was loosing air in at least one tire. I had run over road debris and poked a decent size hole in a tire both times. Neither tire could be saved, but I was able to get off the road and stopped before they went completely flat. Without TPMS I'd have had a tire blowout while driving 70-75 mph and that may not have ended well.

I can replace sensors every 10 years or so for about $20 each. That's about $8 a year and worth the trouble to me. Once the sensors are 7-10 years old I order new ones and let the tire store install them the next time I buy tires. I don't wait until they go bad. Typical life is about 7-10 years. If I wait until they go bad I have to pay to have them installed. No tire store will charge anything to install them while mounting new tires.

 

I’ll start my pointing out that TPMS is more expensive the most peoples Amazon or slime gauges on here. Generally speaking it’s more accurate. To a PSI or 2.

This is because the gauges we buy, (l have longacre in the truck, and a older joes racing gauge in the garage, or maybe my wife put it in her JLR) are calibrated with a certain error percentage, for the good ones. For any of the long range shooting guys or pilots, you’d know that weather (atmospherics, station pressure etc) and altitude play a part in density of air, this effects tire pressure front gauges reading as well. The TMPS, at least in mine, seems to auto correct for this variation.

If you have a regular not $500 field calibrating gauge…then it is what it is. I use the TPMS as a reference to get around where I need to be when airing up, then I set the tire pressure with my gauge to make the PSI even across all 4 wheels. Speaking in generalities again, precision is more important than accuracy when you’re close enough in this case. I doubt any of you are using your taco’s in professional track racing. Ansi calibration spec for a 0-60 gauge is 2% error and for 20-41 psi a 1.2 psi margin of error.

When the tires are cold and I’m back down to lower elevation, I tend to get closer to what the TPMS says…in which case I default to the gauge to set tire pressure.