2 cold mornings and tire pressure warning???

[bender]

ok, so what is the deal?

2 cold mornings now (like 48 degrees) and i got a tire pressure warning. both stated on the computer and the 2nd time i also got a lighted indicator.

i assume its the air being affected by the cold like a racecar's rubber.

thoughts?

...very annoying

[bender]

ok, so what is the deal?

2 cold mornings now (like 48 degrees) and i got a tire pressure warning. both stated on the computer and the 2nd time i also got a lighted indicator.

i assume its the air being affected by the cold like a racecar's rubber.

thoughts?

...very annoying

[Hummer3]

For every 10 degree drop in temperature a tire will drop 1 PSI. The opposite will happen with an increase in temperature also.

[bender]

so i'm supposed to just deal with it?

umm, no

[Hummer3]

I would increase the tire pressures about 5 PSI for the winter months and drop it 5 PSI when warmer weather comes.

[sredish]

Not necessarily deal with it. What happens, and what he said is, the pressure will drop as the temps drop, so when it's cold out, the pressure in the tires will be lower.

You can add air to the tires to make the light go away or you can just go ignore it and the heat will raise the pressure and make the light turn off. As we go into the fall, the temps will drop. There's nothing wrong with just adding another 5 lbs of air if your light is coming on. Simply put, if your light comes on, then check the pressures and do what you feel needs to be done.

[timgco]

There is an issue wth MANY H3's and those damn sensors. Do a search in teh tech section and yo'll find a couple of threads on this. Also, unless your dealer with reapace the BCM, you will contine to have the issue like many of us.

[H3 Hummer]

Put the tires at least 35 if the light goes off in the morning at any temperature above 0 then something is wrong with the sensor.

GM told me the light is set at 26 PSI but this seems low.

[f5fstop]

There are some trouble with some systems; however, On the off-road tires, the cold psi is supposed to be 35 psi (not sure of psi on the standard suspension).
If they are not at the correct cold psi, there could be problems with cold mornings/hot days. I had the same problem in the fall and spring with my Vette which turned on the message at 25, and the tires were supposed to be at 30 psi.

[wannabeH3]

pumped mine up to 35 a month ago and finally last week it went off again... ill just have the dealer replace it when i take it in for the 5000 service

[usetosellhummer]

Moms Buick has them and sometimes I have to hit the reset button in the side of the dash. I don't like them and if you have any non-dealer tire work done you better check em or disable them (dealer may not)

[richk]

The sensor system sucks. Mine goes off everytime I leave the H3 sitting for more than a few hours. I am waiting for my next service to have it looked at.

[f5fstop]

Never had a problem with mine, and the nights are starting to drop quite a bit from daytime highs.
I can't imagine a dealer disabling something that is required by Federal regulations.

[EFnetOper]

Air pressure sensors are required by federal regulations? Since when?

I have had this issue as well. Yesterday, my low pressure light came on and I had 33 PSI in all 5 tires when checked. This seems too sensitive to me.

[HummerNewbie]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by EFnetOper:
Air pressure sensors are required by federal regulations? Since when? </div></BLOCKQUOTE>

It had been in the works for a while now and I believe that all '05 was the last year that they were not required.

[EFnetOper]

Maybe the Fed should also require them to not be so sensitive too. 2 psi change is a bit too sensitive esp when all wheels were exactly 2 psi off.

My wife had to get a ride to work because she was afraid she would end up with a flat.

[usetosellhummer]

they are not required and they suck. disable them! get a tech to do it

[HummerNewbie]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by usetosellhummer:
they are not required and they suck. disable them! get a tech to do it </div></BLOCKQUOTE>

Thought I read a year or so ago that they were required by '06?

[f5fstop]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by usetosellhummer:
they are not required and they suck. disable them! get a tech to do it </div></BLOCKQUOTE>

They may suck, but you don't know the law, so why act like you do? The Federal Regulation is FMVSS (Federal Motor Vehicle Safety Standard) 138 - Tire Pressure Monitoring System.

FMVSS 138 requires that a phase-in period for tire pressure monitoring systems is as follows: 20% of all new cars must comply by Sept. 1 of 2005, 70% by Sept. 1, 2006 and 100% by Sept.1 of 2007

Therefore, GM (as I believe all manufacturers) will install the system on all new launched vehicles; as is the H3.
So, yes they are required, but not they didn't have to be on the H3, it only made sense to GM do design them in from the start.

As to sensitivity, I believe the spec is 25% variance from the tire pressure noted on the tire pressure placard. For the H3, this is 35 psi so if the sensors drop below 27 psi the system will activate.

I highly doubt if any tech will disable them, since it would be considered a violation of Federal law. In addition, I don't believe there is a way to disable them via a Tech 2. Probably have to have a complete different calibration.

Let's also take into consideration how many of these sensors are out there on many cars. GM does not manufacture these sensors, and the companies that do are selling to other manufacturers. This forum is small majority of the H3s sold, so ten or twelve people on this forum complaining does not constitute a large problem.

The largest problem due to the warning, as recorded by engineering is simply the customer does not have the correct air pressure in the tires. On an H3 it is supposed to be 35 psi, and checked when COLD, not HOT.. Therefore, if the tires are set correctly, and the vehicle is parked on a day when it is 85 degrees, and that night it drops to 45, the tires will register approximately 31 psi. This should not be enough to set off the system; however, if the tires are set at 31 psi cold, and they drop 4 psi overnight, then yes, the system may activate.

The reason for this regulation is the general population has no idea about checking air pressures in the tires. Most believe that the oil change shop once every three months is good enough. Problem with the oil change shop is that many adjust the tire pressures according to the label on the door, but the tires are hot. So, pull in your Hummer with hot tires, the guy checks the placard and sees 35 psi, adjusts your tire pressure to 35 psi, and when the tire cools it will lose 3 or 4 psi. Now the ignorant person is driving around and in a few months the ambient temps start to drop. Well, one morning said customer starts his vehicle and the system tell him he is low on air. Off to the dealer he goes, and the dealer has to give him a quick description on how to check tire pressures.

I have known people for years who have had these sensors in their Vettes, I have had them for years, and it seems only on this forum is there that many complaints. Now, I'm not saying there are not bad sensors out there (I had one on my '03 Vette), and I'm certainly not saying people on this forum do not know how to check their tire pressures. People who visit forums like this are usually pretty darn good car/truck people, but the regulations were made for people out there (and they are the majority) who have no idea that tires have air inside them.

Just remember, for any vehicle you own, and if they have sensors, read the recommended inflation pressure on the tire placard, and go with that recommendation, and make sure the tires are COLD (at ambient temperature). Also, understand, they will lose pressure as temps drop, and sometimes air will leak through an aluminum wheel due to porosity of the wheels.

[richk]

Even the dealer can't get rid of my TPM messages. Yesterday the H3 was in for service and they themselves set the tire pressure, re-calibrated the system, poked, prodded, etc. They are dumbfounded. Meanwhile I got tire low messages leaving for work this morning and going to lunch today. And it is not cold out today. Its a wonderful nice sunny day.