how does tpms work ? where's that function on the car ? can you see on the display screen all 4 tire pressures ? or does the icon only come up when your tires are flat ??
Simply put, you use the "SET" button under the dash (near the OBD port) to set the pressures in the tires to the ECU memory. If the pressure drops 8 (i believe) PSI, then the light will come on until the pressure goes back to within the 8 PSI. No, you can not see the pressures on the display. Unless someone can confirm otherwise, the only way to see the actual pressures is to have TechStream and a cable to read the pressures on a display.
Fixed my second tire on this car due to a nail in the tread last weekend. I prefer the older style TPMS that used differential tire rotation as measured by the ABS sensor. It worked when you switched wheels, no fuss, no muss.
Indirect TPMS? Yeah but it won't be as accurate as a direct TPMS. For example if one tyre is more worn than the others
Thanks for clarifying. Although, 8PSI would be just about 25% using factory settings. I'm not sure where I actually saw or got the 8 PSI number, and for all I know, I could have pulled it out of thin air, it sounded good, and I thought it was therefore right lol. You just never know for sure in my world.....
I just assumed that you took the difference between what you saw and what you set it at lol. I say this because we have members that do fill the tyres well above the recommended 35/33 so it's more of a "make sure the information is clear" rather than assume everyone's at the factory setting.
My TMPS indicator lit up last night after I came out of the movies. I checked all 4 tires with my tire gauge and they measured 32 lbs front and 29 lbs back. I drove home without too much concern. This morning I filled them up to 36 lbs all around and the TMPS light went off within a 1/2 mile. I guess the colder temps dropped the tire pressures enough to trigger the sensor. I'm glad they worked - I'm typically diligent about checking my tires but haven't done so since my last oil change.
As to temperature changing PSI I think the rule of thumb is 10 degrees F = 1 PSI drop/rise. But only 36 PSI and front same as back? I check my tire pressure in a garage as close to 70 degrees as possible (warmer in summer, cooler in winter), the pressure drops or rises with temp during use, all that matters is setting it in a reasonable range when the car has been sitting for several hours. The PSI I choose from is: 50/47 high (short trips or warm winters) 48/45 med (long trips or summer use) 45/42 low (winter below freezing) But I have 51 PSI sidewall max tires. If I had 44 PSI I'd probably make that 45/42 high 42/40 med 40/38 low Many priuschat members have found no uneven tire wear at high PSI and the ride harshness doesn't change much once you get above 35 PSI so if you are at 36 now you won't notice much change going to 42/20 or similar.
I've tried running them at 40 psi but I found the ride too harsh, especially going over the bot dots, and it seemed more difficult to keep a straight track down the road. I typically run them at 38 lbs front and 35 rear, but I'm going in for my 20K sevice in a couple days and while they rotate the tires, they don't seem to check psi closely. I've notice no unusual wear and I know they'll likely last another 15 - 20k before needing to be replaced.
I think the TPMS is great. It's come on twice in my car and both times I was getting a flat. It allowed me to pull over promptly and safely and saved the tire from being destroyed.
I run 40/38 in mine and find the ride just fine. I think a lot of it has to do with the tires themselves - as in their makeup, etc. I found the Yoko Avid S33's to be much louder and harsher at 40/38 than my Michelin Energy Saver A/S tires. My Bridestone Blizzaks (Forget the actual model #) that I run in winter at 40/38 are probably in the middle of the two tires. Is there any scientific evidence to show this? No. It's basically how I feel they feel.
I run my OEM Yokos (summer) and Hankook iPike's (winter) at 38 psi all around. On our crap New England roads I get my teeth rattled if I go harder. Haven't had TPMS light yet for me though my wife caught a nail in a tire and obviously the light lit up while the spare was on.
