Low Tire Pressure Warning

[maxm]

I have the LTPW option on my -90 coupe. How does it work ?? Is it the same untill -96 ?
Max M

 

[vettl83]

The 90 and 91's have the same LTPWS's the 92-96 are different. You can remove the 90 and 91's sensors and no code will be set. The later versions will set a code if removed. I may be wrong here but the 90 and 91's just indicate low tire pressure when any tire drops below 25 psi. I believe the later versions indicate which tire is low. 84 CF 91 ZR-1

 

[maxm]

But the -90 does not have eny sensor in the tires. What year did they put sensors in the tires ?
Max M

 

[vigman]

The 90 SHOULD have sensors on the rims

It's a black box held on to the rim with the BIGGEST hose clamp you have EVER seen!


When you turn the key on a Service LPTWS light and a Low pressure light should come on for a second!

Late 88 was the first year it was available.


Vig!

 

[maxm]

Sorry but you must be wrong...the only sensor i can se is the sensor for the ABS. I got new tires during this summer and one day the light came on, i put some air in the tire and the light was gon. But how did the light know that there was air missing in the tire ?? Could the ABS sensors have something to do with it ??
Max M

 

[Tonylong]

I'm not trying to be a smart a$$, but the sensor are mounted INDISE the mounted tire,
in order to see if they are there you must dismount the tire from the wheel.
That's where the biggest hose clamp is mounted with the sensor mounted on it.
There may also be a sticker on the tire rim warning where to place the rim buster
on the tire dismounting device. The sensor is located on the side opposite the valve.
HTH

 

[vigman]

No MAX

That's the way this system works... get a shop manual!



Vig!

 

[6 Shooter]

Make Sure . . .

. . . anyone who works on a Vette's tire/wheels with LTPS are aware of the fact they should break the seal opposite the sensor.

I think some idiot shop worked on my driver's side front tire/wheel and broke it down wrong, ad damaging the sensor. They must have duct taped the sensor back together with 100 mph tape and more than likely didn't tell the previous owner.

The way I deduced it was 100 mph tape, shortly after my purchase I took her up to 135 and the tape gave up the ghost. I must say, a broken sensor doesn't sound good thrashing around inside the tire/wheel.

 

[BlackNBlue95]

Yea When I bought my vette I didn't think to look for the LWTPS Service light to come on.. the Low tire pressure light would light up.. I kinda figured it didn;t have the sensors on the rims because the guy put the Chrome ZR1 look alike rims on.. found out a few weeks ago the sensors were non existant when i mounted my new Goodyears on the rear and someond took the bulb out for the sevice light.. then I thought yea but I probably would have disconnected it.. kinda sucks I dont have a spare either.. ha I have the tire holder for it.. but no spare.. something else I should have checked when i bought it but it was destined to be my vette either way.. LoL now that i'm putting my diff in i am thinking of taking the mounts and hold down for the spare carrier off since I don't need it.. LoL
-Rick

 

[maxm]

Vig...i got the Hines manual...it says nothing abaut LTPW. I belive what you are saying but im still confused. I read somwere that the ABS sensors are messuring the rotation speed off the tire. then wen you loose air the weel gets another rotation speed and you get a light, something like that

So inside the weel is a sensor mounted whit a clamp...hmmmm
how is it powerd...battery ???
Max

 

[vigman]

ABS vs LTPWS

On the ABS there is a notched wheel on the wheel bearing for the fronts and on the splinded drive spindel for the rears

This is a Hall effect sensor where a coil of wire around a magnet is suspended ( about 1/8 of an inch away ) to the face of notched area.

Each time the HIGH part of the notch flies by you get a pulse, much the same way as the HEI ignition circut works.

This pulse train.. gets filtered so to the ABS system it looks like a square wave and the computer may keep track of each wheels rotation..

This system has NO connection to the tire ( as far as wheel internal pressure is concerned)

On the LTPWS there is a piezo electric generator ( like the electric spark generated by a good lighter) which operates when the wheel is in motion.. so no batteries are required,,, FOR YOUR YEAR... later models
(C-5) I believe have a watch battery for their pressure sensors.


Vig!

 

[vigman]

Every picture tells a story ( Scott's fix page)

http://scotfab.tripod.com/index2.html


Or a picture is worth 1000 words



Vig!

 

[maxm]

Now i understand. This was completly new to me. Thanx alot for the information.
Max