I am resetting TPSM but light remains on (all 4 tires are 50psi)

what year is your car? there's a tire pressure reset button somewhere?

 

You might have a bad sensor......you need to be able to diagnose which sensor is not reading properly. Your tires also are way over inflated.....32-40 would be a good range.

 

Each TPMS sensor has a battery in it. One or more of your sensors may have a dead battery, which would require you to purchase new sensors or a rebuild kit, or just ignore the TPMS warning light on the dashboard, but lose the safety feature it provides.

 

If you haven't already, drive the car for a week and see if it goes away. The light will turn off normally if tire pressures are correct with a bit of driving. You could also try a general reset by detaching the negative terminal on your battery for a couple of minutes and reattaching, but I think it's most likely a bad sensor. To diagnose which sensor it is I know using a Mini Vci cable and Techstream will allow you to read the tire pressures, and presumably figure out which sensor is not working correctly. I haven't done this personally.

I also have my tires at maximum sidewall (which is 51psi) and I do not have a warning light on. The warning light only comes on when the tires are too low in pressure (which has occurred to me many times from small leaks - 3 of my 4 tires are patched)

 

I remember the light staying on after inflating the tires after a tire was low until I drove it. I had to drive it a few miles before the light turned off, so see if your drive today clears it.

 

Well first of all, your profile say's 2003?
So I'm a bit confused.

Just for fun....
I'd lower the tire pressure down to the recommendation on inside door jam, instead of inflating to what it says on the tires.
Then repeat the process and see if the light goes out.

It may not, but I'd be curious.
Your tires are way over inflated especially in relationship to the manufacturers recommendations.

It causes a debate every time, but I pretty much just go with the Toyota door jam recommendation.
I believe the Max it says on the tire, is just the max the tire manufacturer believes the tire can be inflated to, but it's NOT a definition of what might be best for your vehicle.

I personally feel 50 PSI is way too high.

 

I tried my old Gen 1 at 42 front/40 rear for just a matter of weeks, long enough for it to pick up a bunch of rattles and squeaks it had previously gone 125,000 miles without developing. They were with me for as long as I had the car after that, even after backing down to a more civilized pressure. Pretty sure that 50 psi will eventually shake parts right off the car.

I'm guessing that the light staying on means there is some problem with the TPMS, aside from low tire pressure. Techstream/Mini VCI will say what the trouble is.

Interesting thing I learned with Techstream (on my Gen 3, anyway): the TPMS reset button sets the low-pressure warning threshold to be 6 psi below whatever pressure is currently in each tire.

Since I saw that, I've formed the habit where on rotation when I have to reset it, I inflate all the tires to 5 psi more than I want, then reset the TPMS, then bleed 5 psi off. That way the TPMS will warn me as soon as they've lost 1 psi from spec.

Contrast that with just setting them at, say, the placard pressures of 35/33, there's no warning until 29 front or 27 rear, which (if I remember right from when I was looking at load range tables several years back) takes a good chunk off load capacity....

-Chap

 

Thanks for the update.
Glad your TPMS seems to be working.

I still think 50 PSI is way too much.

 

50 PSI is too much. The sidewall max pressure is not a recommendation of what it should be pressurised to. It is the maximum pressure not to be exceeded. Considering that the tire pressure will increase as the tire heats up through use, the pressure needs to lower than this so the max is not exceeded.

I'm not sure why you have your tires so overinflated, but I can't see any good reason for it.

If your reasoning is that increasing them from the placarded 35F/33R to 40F/38R lowered the rolling resistance and improves fuel economy, then increasing it more will give a much better improvement. However, it doesn't work this way due to the law of diminishing returns, the most bang for your buck is increasing to around 39-40 PSI. Anything after this, it does not gain you any real improvement when weighed up against the danger you are creating for yourself.

When a tire is overinflated, the profile of the bottom of the tire (the tread area) becomes rounded (instead of the flat it should be) and causes your tires to wear unevenly in the center, and because there is less tire contacting the road your grip and stopping distance is reduced. Read you are creating a dangerous situation by having tires overinflated.

Just thought I'd mention it @MilkyWay in case you were unaware.

 

I have exact issue on my 2011 prius one. Reading horror stories from other members trying to get this issue resolve by the dealer, I decided to give America Tire a shot. I took my car there for FREE balance / rotation. They do the TPSM reset after tire rotatation as standard procedure. I mentioned to them about the TPSM light issue. They ran the TPSM scanner (Free of charge) and determine all four tpsm battery was weak. The signal couldn't send to car strong enough. that is the cause of the lights always on. So there are 2 options

1. Buy the TPSM from America Tire for $60 ea. They will install and program
2. Buy the TPSM from Amazon (Denso brand) then have America tire install it. As of 3/1/2019, amzn sell for $35 each. If you do this route, you might want to buy 1 or 2 extra incase one of them is defective, America can swap right away.

For convenient and I also need a new tire replacement, I chose option 1. Out the door cost for 4 new TPSM, installed and reprogrammed + 1 new tire = $320. This is way cheaper than taking to dealer.

 

Option number 3: do nothing.

 

But then the light stays on.
I don’t know if I would buy them on Amazon. I have heard a lot of bad stories about old stock being sold there.

 

Mines on 4~5 months out of the year, with the snow tires. Unless there's some inspection that'll pull the car off the road if there's a light?

 

But you could get a second set and program them in using tech stream if you wanted.

 

black tape, i know.... hahaha

because i plan to sell this car in few weeks so i want to make sure the next buyer is in good hand. else they will knock 1k off the asking price, lol