Tempremental Tire Pressure warnings?

This is the first car I've had with tire pressure monitoring. All was OK initially, then I got a warning on one tire about a month after getting the car. The tires were all a bit low, with one of the front ones being a bit lower. We were on a trip in the mountains and since the tires were only a little low, so I just "topped up" all the tires to specs once at home assuming it may not have been filled quite correctly.

Today I got another warning! Again, just a bit low. One front tire was showing 29PSI on the MID. Looking back, both times were when it was particularly cold outside, so can see it being temperature related. Is this a case of me needing to tweak tire fillings based on weather to keep warnings at bay? The problem may always have been there, but with TPMS now am I just seeing the issue? I don't want to be dealing with warnings all the time, but don't want to be overfilling to avoid them either?

How do 'yall deal with this?

will

 

@Trollbait: I think it is the same tire, but wasn't paying too much attention the first time. However, it is all four tires that are reading low, just one tire shows 1PSI lower than the rest (measurement error) which I guess was enough to get the low pressure alarm. After the first alarm I carefully filled all four tires to their rated pressures (35 front, 33 rear) plus about a half pound "just because". Looking at the TPMS's afterwards they showed a pound or two lower as I recall, but felt it was within tolerance of my gauge vs the TPMS's.

I don't mind needing to change pressures by season and in fact pretty sure by heading to sea level shortly will need to do so for that reason, but at least here in Colorado, swings can easily be 40-60 degrees back and forth over a few days many times per season. Surely this system isn't sensitive enough that I'm going to have to inflate/deflate every decent-sized temperature swing?

Since I'm about to head to the lowlands, maybe just before the trip I inflate a bit extra now, knowing it will get lower as I descend? Folk caution against over inflating, but if the tires are supposed to be at 33/35, I'm assuming something like 35/37 isn't terrible knowing it will be less within a day?? I did get what I believe to be a good quality tire pressure gauge, so using it as the reference.

This is "laws of physics" stuff, so sure my tires pressure was changing a lot on my Gen1 too, but I just didn't have something measuring and checking it the whole time. Now I see and get alarms, before I didn't. I'm thinking it doesn't matter if it is my gauge or the TMPS's that are the more accurate, it is the TPMS's that are generating the alarms, so should fill to what they say is correct over my gauge.

All sorts of new "problems" by going high tech!

will

 

Thanks @rjparker and @Trollbait. I got the tires up to the placard level cold before the trip and looked at the pressure several times while on the road trip. So exactly 35/33 cold and while driving the front has varied between 37 and 39 and back 35-37. That seems a bit higher than I'd like, especially given I feel they are reporting low compared to my nice tire pressure gauge

@rjparker, how to you initialize the TPMS's? I set them to specs cold the day before the trip and nothing else. Before I was getting a warning when one tire dropped to 29 which is about 25% below 36, so looks like it was reporting correctly.

will

 

OK, hopefully that is the case and I'm over-reacting after alarms. Both were related to the "first freezes", one in the mountains and one at home.

will

 

@HacksawMark: Good news is the only time tire pressure is reading low is on a sudden temperature drop, so pretty confident it isn't a leak. Now that I'm looking for deltas it is OK. But, I'm going to keep looking!

 

@rjparker and @Trollbait: OK, will do some trolling of the manuals. Yes, I do have downloaded versions as I wanted to start reading them before I even got the car! Alas I suffer TEGO easily (The Eyes Glaze Over) when reading that much, so will do some TPMS searching and see what to do.

For some reason I had convinced myself that reported tire pressure would go down as I went down in altitude, so figured being a bit high in Denver would be OK once we got to the lowlands of the east. To my surprise the cold tire pressure went up! Guess I'm not good at guessing on laws of physics. Now that we're going to be in the lowlands for 3-ish weeks, will go ahead and adjust pressure for here.

will

 

Interestingly, I measured the cold tire pressure here in Atlanta, so close to 5,000 feet lower than Denver and the tire pressures were all within a pound of in Denver. But, as I agree with @vvillovv, way too many other variables. Temperature is 50 degrees warmer, the car isn't empty as it was before loading it up for the trip and probably a few other things too. Given the TPMS is measuring +-2lbs from spec I decided to just leave the tires they way they were. They'll like go back up to +4/5 lbs once on the road again, but going to declare that fine and I'm trying to be more precise than is practical.

After the first 1800 miles of this road trip pretty dern'd impressed with the car. If all goes well I can make it from Atlanta to Disney World in one tank + battery with some reserve. It took one and a third in my Gen1.

will