Tire Pressure Monitor System

[RMSAZ]

I was driving my H3 up a mountain (9000 ft elevation and about 30 degree temp drop). The tire pressure monitor warning came on when I was at the top of the mountain. It stayed on until I was back down to about 4000 ft. I didn't have a tire gauge available on the mountain, but when I checked the tires the next morning, they were all at 35psi. I expected to lose a couple of pounds of pressure on the climb, but not enough to set off the warning. Does anybody know the tolerance on the warning system?

[RMSAZ]

I was driving my H3 up a mountain (9000 ft elevation and about 30 degree temp drop). The tire pressure monitor warning came on when I was at the top of the mountain. It stayed on until I was back down to about 4000 ft. I didn't have a tire gauge available on the mountain, but when I checked the tires the next morning, they were all at 35psi. I expected to lose a couple of pounds of pressure on the climb, but not enough to set off the warning. Does anybody know the tolerance on the warning system?

[hyperion78]

maybe it was telling you the pressure was too high. The drop in ambient air pressure due to the climb would have increased the pressure inside the tire. I forgot to check my tires when I was in Utah during the summer and I had driven there from Ohio, and all the tires were at like 70 PSI.... I was like OH ****...

[dchou1107]

i have been having issues with my tire pressure monitor coming on and off. When i last checked my tires i was at 36psi which should be fine. I think that i have a defective sensor but it is hard to pinpoint at this moment.

[DeLeon]

I have the exact same problem.. it goes on an off from time to time... I will ask the dealer to check it next week, I will let you know what they can find.

[RMST]

Every car that I know of that has that technology has problems with it.

[richk]

Mine comes on about once a week and stays on for about 10 minutes then goes away. Looks like the system has bugs. I am going to complain at my next oil change.

[timgco]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by dchou1107:
i have been having issues with my tire pressure monitor coming on and off. When i last checked my tires i was at 36psi which should be fine. I think that i have a defective sensor but it is hard to pinpoint at this moment. </div></BLOCKQUOTE>

Ours does this too. The dealer has had one shot at it too. They are looking into it though. 36 psi is what are 33's are set at.

[RMSAZ]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by hyperion78:
maybe it was telling you the pressure was too high. </div></BLOCKQUOTE>

Good point. I was thinking that the affects of temperature (-30F change) and altitude (+7000 ft change) would offset (i.e., tire pressure increases about 0.5 lb per 1,000 ft of increase in elevation, but tire pressure decreases about a lb per every 10 degree F). But since I did not let the tires cool, the temperature effect was opposite of what I expected. The tires were actually hotter than when I measured them, so the net result was probably about a 6 lb increase in tire pressure.

[f5fstop]

The system is supposed to compensate for barometric pressure from an input from the Manifold absolute/barometric pressure sensor, that signals this manifold and barometric pressure to the powertrain control module. Algorithms are written to compensate for altitude changes.

[RMSAZ]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by f5fstop:
The system is supposed to compensate for barometric pressure from an input from the Manifold absolute/barometric pressure sensor, that signals this manifold and barometric pressure to the powertrain control module. Algorithms are written to compensate for altitude changes. </div></BLOCKQUOTE>

I follow what you are trying to say with regard to engine control, but I don't know how that relates to Tire Pressure Monitoring. The actual pressure inside the tire changes, which is what the system should monitor. It doesn't matter if the tire is at sea level or 15,000 feet - too much pressure is too much pressure.