GM / General Motors: Low Tire Pressure Alarm

Generally the wheels are equipped with a strain gage that sends a
signal that activates some type of enunciator when the air
pressure drops below a predetermined setting.


mike hunt



"" wrote: 

RJ wrote: 

Contrary to the opinions of others, I can tell you the truth according to the
Helm manual. In the Antilock Brake System, you have wheel sensors that can
determine whether each wheel is turning, or locked, or whatever. The sensor
does this by counting revolutions of the wheel. As long as all four wheel
sensors count the same number of revolutions for a given distance traveled,
then it is assumed that all four tires have the same circumference and hence
the same tire pressure. You can get into a weird situation if you have
mismatched tires and/or pressures. If the system sees (for example) 100
revolutions on three tires, and 99 revolutions on the fourth tire, then that
passes. But if it sees 100 on three and only 90 on the fourth, then the system
will display a warning. It is calibrated to warn by the time one tire is ten
pounds low, as compared to the others. That is a lot. Typically, it will alert
before one tire is five pounds low. Mine alerts at about three pounds low.

---Bob Gross---

"<RJ>" wrote
 

Read Bob's post for how your vehicle works. On some
other GM vehicles, there are actually sensors that are
built into the valve stems (very special valve stems) and
they are also small transmitters that will send a signal
to the vehicles computer if a tire is low. Whenever you
rotate tires on this type of system, you must relearn each
tire to it's new location. Special tool for it, and wouldn't
you know, it doesn't come with the owners manual.

Ian

Thats really "rocket-science" amazing !
Thanks so much for the explanation.

<rj>


On 24 Oct 2003 19:01:55 GMT, com (Robertwgross) wrote:
 

<rj>

Think about what you are just said then think of how a
differential works and what happens when your make a turn.
once you have done that you will realize why your theory can
not possible be correct. New regulations require all vehicle
to have tire pressure sensors and not all vehicle have ABS, is
another clue. The pressure detector that sends the signal is
inside each wheel.



mike hunt



Robertwgross wrote: 

to relearn the tire sensors on a vette, just use a regular magnet.. using
the prompts on the dic, it works like a charm.... Bobo

"shiden_kai" <com> wrote in message
news:X%gmb.1084$.. 

"Bobo" wrote
 

Hey, good idea....Bobo. I realized that the tool is simply
a magnet, but didn't pay much attention to the fact that
probably any magnet will work.

Ian

<com> wrote

 

Phew....you better stop now, my good man. You are way
out to lunch and really don't have a clue about what you
are talking about. Just drop the subject and folks will
forget about your stupidity in a week or two.

Ian