Uneven tire pressure?

Fill them up to a higher pressure like 45 and then air them down to the correct psi .

 

get a good tire gauge.

that being said, nothing is going to give you the kind of accuracy you're looking for, put the ocd to bed.

 

The onboard sensors are not perfect.
Neither are a lot of manual gauges.
Neither is the "automatic" feature of the pump probably.

Worrying about a 1 PSI difference is foolish.
Why are you running 42 ?

 

Post 2
Over fill and bleed down.
Remember to do this when the car has sat overnight.

Maybe your issue is you are checking pressure after driving?

Digital tire pressure gages that read in .5 pounds are not too expensive.

My rant: We send "missions to Mars", yet a accurate tire gage that reads in 1/10 of a pound is not readily available.
I am not a fan of dial gages because of that .5 pound accuracy and my OCD LOL

Good luck wished.

 

If you're talking about the reading on the dash (screen,) it's probably the sensor inside the tire.
It's not a 'bad' sensor it's just not voting the party ticket in this cycle.
That happens.

If you're going to be this OCD about the tire pressures, then get a decent HAND gauge.
I use dial-types, but then I have too much bench time calibrating electronic pressure and temperature sensors to put much faith in them, and like the US Government, Toyota gets their sensors from the LOWEST bidder.
Dial gauges also do not require batteries that fail when you REALLY need them.

OK?
So...

As others have mentioned, run your tires up to the max sidewall pressure with the "not"-free nitrogen.
Then drive home, and wait a while.
Have a pop
Read up on what the Saints are up to, and maybe dig some old Mardi-Gras beads out of the grooves in your tires.
Then?
Use the bleed-valve (little button on the stem of the gauge) to adjust the individual tires to YOUR desired pressure....or.....the pressures indicated in the sticker in your door jam if you're that kinda person.

THEN....
Note the values indicated on your dash and/or infotainment system.
If one of them is off?
Then it's OFF....but don't be too hard on it.

TPMS stands for Tire Pressure MONITORING System....not Measuring.

You're looking for trends.....not absolutes and the purpose of the TPMS is to illuminate a light when there is a significant drop in your tire pressure(s) in a vain attempt to thwart the beneficial effects of Natural Selection.
It's sort of like the backup cam.
A nice visual aid, but if you have a three-digit IQ you're still going to use the mirrors...


Good Luck!

 

The underlying pressure measurement is inherently analog. In any analog measurements, a single unit difference between two measurements doesn't necessarily have any meaning at all. It is definitely nothing to be concerned about.

All analog measurements contain both noise and sensor accuracy uncertainties. When two measurements by different sensors differ by a single increment, the actual difference could be as high as (2 increments plus 2 times the sensor accuracy plus measurement noise). Or it could be as low as (Zero minus 2 times the sensor accuracy minus measurement noise), i.e. a negative number.

Yes, that means your 42 psi tires could actually have less pressure than your 41 psi tire. This possibility covers only a small part of the probability distribution, but is quite possible and not rare at all.

Before fretting over possibly nothing, get some tire pressure gauges that read and are calibrated down to 0.1 psi or better. The fact that many tire pressure systems round to the nearest 1 psi comes from the fact that this amount is not significant.

 

My rant: complaints that compare the cheapest consumer products against $3 Billion dollar projects.

If these consumers were willing to spend $billions, they could buy vastly more accuracy than 1/10th of a pound. Heck, they could probably get 0.1 psi for just $dozens. But few consumers are willing to pay extra for that accuracy.

 

^ The $3b project is mostly labor.
That's why Elon is getting fantastically rich by lofting cargo to LEO at less than $3,000 a pound.
He's LITERALLY the Henry Ford of space "exploration."

The last sensor array that I helped build and calibrate for dot.navy.dot.mil was for a fantastically expensive....ah......"study" in exploring the idea of detecting abnormal vortices in certain parts of the ocean...perhaps caused by large mobile objects that might cause these....ah.....disturbances in what might normally be a fairly predicable profile.

Think of it perhaps as a good method of tracking our oppressed marine mammals....

Anyway.....we were given specifications for things like thermistors and WE did what ANY OTHER contractor/subcontractor does....which is look for the cheapest source for these parts. This was long enough ago that I LITERALLY went and bought some thermistors from Radio Shack to use in a test array to validate the larger array, and we later sourced the same units from THEIR distributor because they were cheap....and "good nuff."
We did the same thing for pressure sensors, and some other stuff.
We used C.O.T.S. (commercial off the shelf) absolutely as much as we could to avoid the $300 hammer......which is almost always a commercial hammer, bought specifically for a small number of platforms that has to be "certified" to work on that platform....sometimes by civil serpents, sometimes by contractors overseen by civil serpents.
Trees are felled by the hectare (sometimes, literally!) to document these efforts.
All too often the $15 hammer is bought by a "disadvantaged"-owned firm that receives an RFH (request for hammer) from a contractor.....buys it from Sears, adds a handling fee, and sends it on to the contractor without even bothering to remove the "CRAFTSMAN" label.
These are the GOOD guys, because you at LEAST get a decent hammer for your $300.

That's why MY rant is people expecting dot.gov stuff to be orders of magnitude better than COTS while fussing and cussing at the $300 hammer.

Thing is?

NASA does not build satellites, and people that DO build them use the cheapest parts that they can find when and where a COTS solution is possible......
.....just like car companies that will punch out 300,000 examples of a particular car and EXPECT a failure rate of faaaaaar less than one in 10,000 pressure sensors.

Believe it or not?
Car manufacturers actually source good parts.
They HAVE to....Because UNLIKE NASA, they have to operate within a real-world budget and strive to make a profit.

 

1 PSI isn't going to make a speck of difference - stop worrying.

 

And possibly premature wear out of bearings and suspension. And then there’s dental filling repair...

 

One psi on one tire?? Better get that puppy back up to 42 psi right now or it'll cost about a pint of gasoline over the lifespan of the car.

As @alanclarkeau said, one psi won't make a bit of difference. Especially once you're up to 40 psi anyway.

 

Im not a fan of over fill the tires. I keep mine in spec , My AWDe is 36psi front, 35 rear. Anyways, get a good tire gauge. the ones on the air pump aren't accurate.

 

The other thing to consider, no gauge is correct anyway, particularly if you've driven there, as they warm/heat up as you drive. No 2 tyres heat up exactly the same, as they're doing different things, so by the time you get there, unless you live next door, a ONE PSI difference will probably not be ONE anyway.

I pump mine to 280 FRONT, 270 REAR at the pump - then drive home - next morning when cool, they're roughly as specified. If I'm going to drive any distance, before I set off I re-check them, again in the morning when cool. But normal commuting, as @jerrymildred says, it might save you a teaspoon of petrol over the life of a car.

With Nitrogen - it's not worth the bother, unless you drive past - unless you're driving an 18 wheeler Jumbo Jet, there will be no measurable improvement on regular 78% Nitrogen.

42 (psi) might be too high anyway - I'd rather pay for an extra litre of petrol over the life of the car than to be replacing bushe$ and damper$ etc (or as someone mentioned, tooth fillings). Have you checked TOYOTA's recommendation? In almost all size combinations, TOYOTA stipulates a different pressure front&rear, not the same - and it's nothing like 42.

 

What units are those Alan?

I usually go by the higher of the two, set all for to that. And maybe 1~2 pounds over, no more.

 

kPa

The difference between front/rear can be for handling. I had a FWD Renault which, from memory was (in PSI then) 27 front, 35 rear. The mechanic at service set them both the same. And it was almost impossible to drive, massive oversteer.

 

I would also point out using a higher in pressure than spec, you are actually decreasing the contact patch of the tire to the road. By going with higher pressure , your tire are budging in the middle

 

Yes, possibly - that was definitely the case with old Cross-Ply tyres - Steel Radials tend not to do that anything like as much, if at all, except beyond certain limits. (You could do that by reading the "MAX PRESSURE" off the sidewall and set it to that - as I've heard suggested in the past).

But - yes, you could be correct IF TOYOTA have ALREADY specified pressures at the upper end of that scope, in order to achieve better economy.