Low tire pressure sensor

[Bob Burns]

Yesterday was the coldest day of the season so far, 27 degrees. When I
went out in my '08 Outback, the tire pressure light was on. Temp
outside was 30 at that time. I went back home and got the other car.

Later in the day, I checked and pumped all the tires up to 34 psi.
Sticker is 32 front, 30 rear. One of the tires was at 28, the other 3
at 30.

Today I went out with the temp about 35. Low pressure light was on for
about the first 5 minutes, then went out.

So, what's happening here? Is the sensor sensitive enough to pick up 28
psi? Is this just an effect of the low temp? Should I just ignore it
on cold mornings?

TIA!
--
-------------------------------------------------------
"Every day is Saturday when you're retired."

Bob Burns
Mill Hall PA
(email is a spamtrap)

 

[Greg]

Most systems will trigger a warning at 2psi below spec.

 

[Bill Bradley]

I have a 2007 Legacy 2.5 GT, and, several times, without it being really
cold (> 50 F) my light has gone on (why it can't tell WHICH tire, which
might have cost $5 more, is crazy), and...all tires were at or above (and,
sometimes, I even filled them above) the required pressure.

Every time, even though I seemed to be at the right or higher pressure, the
light didn't go out for over 20 minutes of driving.

 

[bigjim]

Tire pressure systems seem like another thing to pull the fuse on nd
forget about that government mandated garbage. Disble DRL's and
airbags too. Darn guvmint dont need to take care of me!

 

[Frank]

Tire pressure systems seem like another thing to pull the fuse on nd
forget about that government mandated garbage. Disble DRL's and
airbags too. Darn guvmint dont need to take care of me!

I'm with you. My wife mentioned this about new Forester. I await her
sensor to come one!

 

[tcassette]

Yes, I found that measured pressure a bit below about 30 pounds can trigger
the alarm. Plus, most pressure gauges probably have about the same accuracy
tolerance as the tire sensors; worst case, you may measure 32 pounds and the
tire sensor says you have 28, when in fact you have 30. That said, I have
never received a low pressure alarm when maintaining the 32/30 psi per the
sticker. As noted in the manual, a few miles of travel may heat up the
tires enough to clear the alarm. I agree that the system should tell you
which tire is low, but it is better than nothing. Just notice all the folks
with dangerously low tire pressure next time you are out in traffic.