mrlexus12

Hey guys

first of all my cars tpms is way off. Computer tells me my tire pressure is 28 psi in all 4 wheels. I checked it manually with a pressure gauge and the pressure in all 4 tires is a sweet 34 psi.

how do I recalibrate my car’s sensors to ACTUAL TRUE pressures? Is my independent analog gauge off? I doubt so. It is high quality Made in Italy pressure gauge.

secondly the tire warning light is on and I have reset it and it does not reset.

st1800

I don't think there is any way you can calibrate the tire pressure readings. Most tire pressure gauges are off, doesn't matter how much you paid or where it was made.

Try disconnecting the battery neg cable for 15 mins, and then reconnect and reset the the tire warning light. You'll lose some radio, etc presets, but worth a try.

Tootsall

You could also bleed a couple pounds off one tire and see if TPMS picks up on the change. That’s what I’d do first to see if the system is working properly.

12jimmyjam

I’ve noticed that the cars guage differs from the ones used at home and at gas station auto pumps on my 13 es300h.

Mike728

Mine have always been within a pound, so pretty accurate. I would get a second gauge, just to make sure. The reason your light is on, is due to the vehicle showing 28 lbs.

st1800

"The reason your light is on, is due to the vehicle showing 28 lbs."


^^^^^

jamestpc

Do you have a second set of tires stored in the garage that also have sensors in them? I know my winters on their rack sometimes chime in and messes up my readings while in the garage...

Tootsall

Mine do that too, I get “—“ but within half a block the readings are fine.

SpaceGravy

TPMS systems are notoriously spotty, even with premium Japanese engineering such as in a Toyota product. You could buy aftermarket sensors, a programmer and re-do them all but it's quite costly even when you do the work yourself. Another system that is not spot on accurate is the mpg computer estimate. I've gassed up on a dry tank and done the calculation and my actual mileage shows to be about 2 mpg higher than it really is. First world problems indeed :-)

Tootsall

Say whut?

TechNut

I’m not sure how this relates to the TPMS topic of this thread, but my observation is very similar. If I am understanding your comment correctly, you are saying your dash shows about 2 mpg better than you get when calculating by hand. Our mileage typically runs 1.5 to 2.0 mpg lower than the dash gauge when calculating by hand. It varies somewhat with seasons and type of driving.

SpaceGravy

Yes, I didn't say that very well but the computer's calculation of the mileage I was getting was about 2 mpg better than when I did the calculation myself. I've just never really heard of these estimates being very good but Toyota/Lexus are probably the most accurate of the bunch.