Low Pressure light

ares89 · 09-11-2007, 10:46 PM

OK.. i got the new rims on last week, on the light is on. How exactly is the tire pressure monitored because the stock rims i believe you need 32psi and with the new ones my bro was sayin they get 38psi(the alero was his before me so i was goin with what he said..)

[ion] C2 · 09-11-2007, 11:08 PM

dunno i went down to 25 PSI for the track and my light never came on

SIUlero · 09-11-2007, 11:50 PM

it actually monitors how fast the wheels are turning...when a tire is low on pressure, it acts like a shorter tire, and has to turn faster to keep up with the rest of the wheels. it would see the same thing if one tire actually IS shorter than the others too, and turn on the light

ares89 · 09-12-2007, 12:04 AM

i would have sworn the radius of the tires was the same between stock and the new rims... if the sizes are diff after all, is there a way to reset it so it doesnt have the light on all the time?

rustyballs_69 · 09-12-2007, 12:11 AM

It depends what tire and rim size you have too. My alero with the stock 16's and factory rubber is 44psi. I have a 2001 with all options except the leather, I don't know what tire size came on the 15 inchers if thats what you got.

This is out of the Haynes manual, The tire pressure monitor system will turn the dashboard warning light to let you know if any tire is 12 psi lower than recommended. If you change your tire pressures, get new tires or have yours rotated, the check tire pressure light may come on. To reset it, turn the key on (engine off), then push once on the reset button in the driver's side interior fuse panel. Press the button again after you see the oil change light flashing. When the check tire pressure light begins to flash, push and hold the button agian until a chime is heard, then let go.

ares89 · 09-12-2007, 12:12 AM

thanks.. will try that tomorrow when im awake.. heh

SIUlero · 09-12-2007, 01:24 AM

if all the new tires are of the same radius (as each other, same or different than stock doesn't matter), it shouldn't make a difference, the wheels will all turn the same speed together...it's only if you're running mismatched tire heights that you should have a problem

Cliff8928 · 09-12-2007, 02:14 AM

Quote:

Originally Posted by rustyballs_69

My alero with the stock 16's and factory rubber is 44psi. I have a 2001 with all options except the leather, I don't know what tire size came on the 15 inchers if thats what you got.

Ok, first thing is you don't fill the tire to the pressure it says on the sidewall! That is a MAXIMUM operating pressure. The recommended pressure is located on a label on the drivers door or jamb.

Kilroy · 09-12-2007, 02:34 AM

Quote:

Originally Posted by Cliff8928

Ok, first thing is you don't fill the tire to the pressure it says on the sidewall! That is a MAXIMUM operating pressure. The recommended pressure is located on a label on the drivers door or jamb.

That only applies if you are running STOCK wheels and tires. Change brands, and that sticker means nothing. Different brands and different types of tires could require different pressures.

SIUlero · 09-12-2007, 02:57 AM

Quote:

Originally Posted by Kilroy

That only applies if you are running STOCK wheels and tires. Change brands, and that sticker means nothing. Different brands and different types of tires could require different pressures.

The number on the tire is still only the max for the tire...the factory psi may not be exact for an aftermarket set, but it's going to be close to what should be used. best thing to do would be to get your vehicle's actual weight and contact the manufacturer of the tire for the optimal pressure. Most people won't go to that trouble though. In any case, DON'T run at max rated pressure...that's just asking for a blowout.

lonnie · 09-12-2007, 07:39 AM

I got rims and my light came on when I had a slow leak. Doesn't matter what sensor is measuring, all that matters is that you have a slow leak somewhere, and unless the sensor is bad then you need to check your pressure. I keep all my tires at around 40 psi, and when I got the light and checked I had like 30 in one tire hence the light. Fixed it and reset and no problems until I got another leak.....Damn screws and nails!

jayson_waltz · 09-12-2007, 09:20 AM

jeez peope, i run my tires at 30 psi, exately what it says on the door. I run the front at 28 psi around town in the winter.

teflone · 09-12-2007, 10:10 AM

Ok first of all.. it DOES measure pressure

Not radius...

It will only bring on the light when one tire is 12-15 psi under the average of the rest of the tires..

So if you have a bunch of slowly deflating tires, that deflate at the same rate.. its useless, because all the tires will be within 30 percent of each other

Now.. it does not read increases in tire presure, so you could theoretically reset your tires (fuse panel reset) to an extremely low pressure, and you'll never see the light again.. untill you reset your tires to a normal pressure

I have had issure with two tire slowly deflating..

My fronts were perfect all the time, new rubber no loss of air

My back two deflated slowly, and one fast than the other..

I would reset the TPM (Tire press. monitor) to 33-34 PSI
and the back tire would make it down to 20 psi before it would trip on the bad tire.. the other tire was 25

But that made the over all average that much lower, so it would take a while for it to trip..

Hope this helps

a full description is in the manual I believe.. I remember reading all this somewhere..

SIUlero · 09-12-2007, 05:01 PM

find me a tire pressure sensor on our cars...you won't, because they don't exist. The computer monitors the wheel speed sensor, like I said before...these aren't hummers, which do (did) have the option of a sensor specifically for tire pressure monitoring

[ion] C2 · 09-12-2007, 05:37 PM

he's an autozone parts specialist, don't doubt him teflone

Redog · 09-12-2007, 06:09 PM

Is it 30? I thought it was 35

teflone · 09-12-2007, 06:20 PM

Quote:

Originally Posted by [ion] C2

he's an autozone parts specialist, don't doubt him teflone

I dont care if hes the queen himself.. Im just telling you HOW it works..

wether it measures it that way or not, the point is still the same..

Read your manual..

[ion] C2 · 09-12-2007, 07:24 PM

<--sarcasm intended

TheEdgeofSanity · 09-12-2007, 09:39 PM

ok. if you read the manual, it says that it will only measure extreme changes in tire pressure (a blowout or nail hole) so chances are that there isn't any sensor in the tires not to mention that there isn't one when i take the tire and rim off. It probabily measures the loss of air by the way siulero said by having a certain ratio between lost psi to decreased radius and when a certain amount of radius is lost in a hurry, then the computer determines that these has been a large loss of tire pressure which makes the light go on. i think its funny how most people want to believe that the alero is as sophisticated as a corvette or hummer that have sensors for anything you can think...

TheEdgeofSanity · 09-12-2007, 09:41 PM

and, you have to keep in mind that the manuals are written so they make sense to any idiot that may be driving the vehicle. they simplify everything and usually don't go into detail on how systems work.