yesterday it showed me R32:28psi . today it went to R30:20psi !!!!

so i took it to an auto garage and had it checked. the pressure gauge were showing 32 on both rears.. still, on the trip-computer it showed me 30:20... so i asked the guy to raise that to 35psi.. and he did on all 4.. but the trip-computer still reads 32:28.

what am i missing here??

 

The TPMS always reads a couple PSI lower from my experiences.

Could be a sensor going out?

 

^maybe that... but i don't know for sure, and if i ask the stealership for a checkup and replacement, they're gonna ask for a huge chunk of money.

could a tire tread affect the PSI?

 

Tire tread wouldn't have any effect on the internal PSI. I assume all your readings are "cold", i.e. you haven't been driving the car for the previous two hours, etc.

One of the sensors may be flaky. Perhaps getting it reset will clear it up.


You do realize than when you add air, you have to drive the car for a while for the new pressure reading to register. The sensors only start reading when you speed gets over 20mph and they don't get picked up instantly.

 

yea, i know that^.. tho, i drove it for over 20mins today with speed ranging between 40-80mph, it still read 30:20. and after adding air, i drove it for over 45mins.. and "hot" reading was @ 32:28, while i had them set on 35psi at the garage.

reseting the sensor requires the dealership? there isn't a DIY so i can save my money?

 

Naw, it takes a special tool to do it. It's basically some kind of magnetic device that they touch to the valve stem. A lot of tire shops have a tool that can reset the sensors. Only the dealer can do the diagnostics on the computer side of the system.

 

...... stealership to the rescue. i'll probs take it to them after couple of months. but i'll be checking real PSI between now and then.

thnx for the input, guys.

 

another question... how can i tell which sensor is on which wheel?? cuz i think the rears are swapped.

i thought about releasing some air from one of the tires and check on the TPMS to see which one lost psi. but is there any other way?

oh, and btw, it's reading 32:16 now! very low.. i still didn't take it to the stealership, i'm trying to observe what's happening.

thnx

 

crazy idea, but maybe you should get your tire gauge out and check the tire yourself? looks like you have a leak...

 

i don't think it's a leak, cuz at spot when i had it filled with air, it showed on the filler gauge 35psi, and when i just moved to have the new reading, the trip computer showed 28psi. i wouldn't be loosing 8psi in 2mins, cuz otherwise i'd have a flat tire by now.