Tire Pressure Monitor

Yeah, that's the reading off from TPMS sensor. I dd not know 2020 Prius has that ability. Did you keep it very high before taking to the service? The TMPS sensor reading is usually very accurate, but to be sure I suggest checking with manual tire pressure gauge and adjust to the pressure on the door plate. It's 36/35 for PRIME but not sure for regular Prius.

 

That probably means either:
The did NOT check the pressure at the shop.
OR
They are morons who think the number on the sidewall is a "recommendation" and your left front one is leaking.

So, yes, you should put them back closer to the recommendation, do a "reset" on the TPMS and then look again in a few days.
Tire pressures are set COLD......meaning not having been driven and not sitting in the direct sun very long.

 

I'll differ from the other answers as the car manufacturers tend to emphasize comfort over performance and suggest a tire pressure that is lower than I would use. First check the tire sidewalls for their MAX low temperature PSI, You should never use a higher pressure than that MAX (Usually 44 PSI, but my preferred tire, the Nokian WRg4 is listed as 51 PSI). I inflate my Prius tires to 42 rear and 40 front even though this gives a somewhat harsher ride, the benefits are:

• Better handling
• Longer tread life (reduces tread edge wear)
• Higher MPG

My 2004 Prius had Toyo tires with very soft sidewalls and really needed the extra PSI or they would wear out in 15k to 20k mile. They lasted 40k miles for me at the higher air pressure. This is from experience gained in over 300k miles and 16 years of Prius ownership.

JeffD

ps: Thanks to the OP for pointing me at the ability to read the PSI from the app, I did not know that that capability existed in my new 2020 Prius. But you do need to look carefully at your left front tire for a slow leak.

 

If they initialised it with those pressures it will need re-initialising once you have them set correctly.
IIRC the warning comes on when the tyre pressures drop 20% (or it may be 25%) so I inflate them 20% (or 25%) higher than recommended pressure to initialise the TPMS, then drop the pressures down to 3-4 psi above recommended. That way I get an earlier warning, that is when they get under recommended pressures, rather than 20% (or 25%) below.

 

I see you are at California. In California theres a law that says something like "All under inflated tires will be inflated to manufacture specs, all overinflated tires will be left as is." Saw something like that in one if my service receipts

 

Maybe you've got a slow leak on that low one.

You don't need an internet poll lol: check pressure with a pressure gauge, and maybe take off the low one, check the tread for nails and spray it with soap solution, if needed.

 

What exactly makes you think that is a "law" ?
I know it's California but it sounds more like "store policy" to me.

 

If you need a source...
Tire Pressure Program.

 

Nice try. But nothing there says anything about NOT touching tires that are over-inflated.

Care to try again ??

 

I answered your question... It's law that service shops in California have to check and inflate tire pressure if it is UNDER inflated. The law does NOT require service shops to deflate OVER inflated tires. As a resident of California, I know this is law (and also cited the law), how is it so hard to understand?

 

You did not answer the question that I ASKED, nor did you properly address the part that I was disputing. (quote above)

So far, we have no evidence that there is a requirement in the rules for "all overinflated tires will be left as is."

Apparently the law says NOTHING about over-inflated tires.
Which does NOT prohibit doing something with them OR asking the owner about it.

 

Technically, they should not touch an over-inflated tire. Especially in the hot months.

This is because as the tire gets hot, hot air makes for more pressure. If they were to deflate the tire now, then at night when the temps come down, the tire becomes under-inflated as it cools down. But this is only by a few pounds of pressure.

The MAX PSI number on the sidewall has to do with load. The burst psi is much much higher. So don't worry about those, unless the dealer wanted to kill you or make you come back to get new tires.

All that said, the dealer is very ... scummy. Or inept. I took my Prius for one of the free services during the first 25k miles and when I got home, I checked the tire pressures.

The tech did a tire rotation, but never bothered to check the pressures. The front, which are now in the rear, had higher pressure than the rears, which are now in the front.

 

You asked if this was a law in California, which I confirmed it is. We are agreeing on the same thing here, Nothing wrong with asking the service provider to deflate over inflated tires, but not suggested as another poster pointed out.

 

Unless I'm missing something, there is nothing in the link you posted that references "overinflated tires."

 

Leaving "overinflated tires" part was anecdotal. I saw that in one of my ROs. My point is service stations in california are required to check tire pressures

 

As originally stated, it is NOT.
At least not based on the information you supplied.

 

Aha, the data is directly from the ECU. There are no location sensors in the car. So even if the sensor ID registration was done correctly, at the subsequent rotation they may not be located at the right corner of the car.