well as the title says, my tire pressure light keeps coming on after some driving. I check the air pressure and it reads about normal (37psi). I don't know what gives?

I know the pressure will fluctuate depending on the outside temperature. It has been about 77F around here lately. Anyone know how it works exactly? From what I remember, when its hot the air in the tire expands?

Another question...is the tire pressure light only an indicator that a tire(s) is low in pressure or too high?

 

Why is the pressure so high? I believe the door plaque says 30 psi front and rear.

 

You are correct, depending on the tire you're running.

 

I had this issue as well - the indicator light would seem to come on if I had been driving at 75 or so for a while and then got in traffic doing 40.

Took it into the dealer where they quickly realized it was because I had my spare on (other tire was punctured - got it replaced but just kept that one as my spare). They had to register the sensor with the car which has (so far) prevented any recurrence of the issue.

As for the high/low pressure - the manual has more detail on it. IIRC, it detects only low pressure which is ~26psi for the sedan.

 

Make sure you check the tire pressure when the tires are cold. The best time would be early in the morning after the car has rested over the night.
The recommended pressure for stock tires on a 05 G35x sedan is 30psi.
My delaership had it set to 37psi when my car was deliverd and i drove about 400miles without noticing. The ride was very bumby and harsh. I then realised it could be the pressure and found them to be 37psi.
I immediately lowered to 30.5psi and it looks good so far.

Is it confirmed that the tire pressure sensor does not detect High pressure and detects only Low pressure.
Is 26psi the low pressure limit?

 

from section 2-12 of the 2005 manual (page 82 of the pdf):

I don't remember any chime when my light came on, but I usually have the windows open or the radio on...

 

hmmm interesting...i'll check the pressure tomorrow morning, I've already driven the car today. When i DID check the pressure and it read 37psi that was after some driving during the day. It was pretty warm.

There is no chime when the light comes on. The only thing I can notice which is somewhat like a pattern is that the light comes on when its warm out and i've been driving about 30 minutes.

 

Seems like a faulty sensor... Mine came on once with a chime - definitely hard not to notice the sound. Right rear was low (nail puncture). Seems to me that since it's consistent and no chime, there's a short or bad sensor. I'm sure a trip to the dealer is on your "to do" list.

 

ahh i see...damn i took it into the dealer last week...damn advisor said it would get looked at. Time to raise some hell...

 

My 05 has a long, single BEEP when the sensor illuminates.

 

From what I understand, the pressure sensor will detect too low and too high pressures.
The stock pressure for your ride is 30 psi cold. I used to run 32-33.
Check them cold and adjust.
C.

 

Awesome bit of info...Thanks!!

 

Well i checked the pressure this morning and it read the same (about 36psi) I checked the door jam and it said the pressure should be 33psi. So i lowered all the pressures to that amount. Hopefully the tire pressure light doesn't come on.

 

From my understanding, when cars are shipped, their pressure is set to about 50psi. This is so that tires don't go flat over the overseas trip.

The higher the pressure, the "bouncier" ride, better gas mileage, less handling.
Lower tire pressure, more grip on the road, lower gas mileage, more wear on treads.

 

Any way to eliminate the beep or chime or whatever I am about to hear when I drop on my new 19" Hiro's that arrived yesterday?!?!?!