Ongoing issue with loss in tire pressure

That's what I have to think.
Like I said, It's not rocket science, air is leaking. And there has to be a finite amount of reasons it can be leaking.
Strange though that it would manifest with 3 out of 4 relatively brand new tires. But I suppose it can happen.

 

It may not be the actual tires that are the problem.
There have been cases in the past where the rims actually leaked.

You need the services of a good old-fashioned tire mechanic to actually look for the leak, wherever it may be.

Also it's time to contact the Toyota warranty help line.

 

Questions of responsibility aside, for me its not worth the time and aggravation when a quick trip to the tire shop can resolve the issues for very little cost.

The simplest explanation being the most likely, the car was driven over something and picked up the leak(s). Again, any competent tire shop can answer all questions. Being right isn't always so important, it doesn't matter when its so easy to resolve. If it does turn out to be a defect in materials or workmanship then there's ample recourse to pursue that with Toyota. If it turns out to be road hazard, its not Toyota's problem.

 

Although a tire shop could "possibly" resolve this issue faster, there are to may variables and cost liabilities given the limited read of a forum thread. By the way, FOD means Foreign Object Damage which would put the responsibility back on the owner and Tire Warranty included with the new car handbook/package. Assuming this is not the case and it being a two month old car....Dealerships problem. I stand behind my recommendation. YMMV.

 

I would ask what the Mfg date on the door is.
If there was a long time maybe the tires were just at 29 psig at the dealer and with winter coming on they went down another 3 psig. And maybe a nail in the one tire.

 

Anyone know when/where the TPMS valves are installed? Factory or Port of Entry?

 

What the dealer or tire shop should be doing but which you can do in a few minutes:

1. With fully (35PSI+) inflated tires. Take a bucket of water, some detergent like Ivory soap known to bubble up, mix into a dense with soap mixture. Take to car. Remove hubcaps if present. Slosh the mix heavily over inside of rim area especially where rim and tire meet and over entire valve. Observe if and where bubbles form.

2. Tighten valve stems (the metal portion only visible after you take the cap off).

If they haven't done both, they aren't really trying.

Mention that you will have to report the issue to the National Highway Traffic Safety Administration as a safety issue when you discuss it with Toyota corporate. If not quickly resolved, do report it to NHTSA.

 

While that works for some situations (most), sometimes the wheel needs to be removed from the car and immersed in a tank of water.......and left there undisturbed for maybe a half an hour.

 

And none of the basics that Easy and I suggested simulate running the tire under load on the road. But they are the basics.

 

Most of the suggestions here are standard industry practices (SIP) used to detect leaks on wheel assemblies. Sharing one's preference or "what they should do" is fine for others reading that might not already know, but the situation here is different.

Again with the premise she did not run over a box of tack nails or something...

The young lady who started the thread has a 2 month old car with three tires that have leaked down at least twice until the TPMS flagged her @ between 500-700 miles each time, with the Dealership not finding or fixing the problem. Should she have either changed out the flat one before it was ruined or called for the "included" 24/7 free roadside assistance?...YES...which is why they probably charged her for the replacement tire. HOWEVER...considering the history, age, lack of miles on this vehicle and their apparent inability to fix this problem, her Dealership and Southwest Regional (best guess from her post) should be jumping though hoops begging for her forgiveness, doing everything they can to fix this now...in addition to giving her money back on the tire. Folks don't get me wrong for saying this (not that I care), but most Dealerships take advantage of women...and we all know it.

 

That this occurs only while running suggests valve stem seal with rim, or rim porosity or rim crack.

 

I'm not sure that is true.
Maybe the car runs every day......and it wasn't being checked very often either.
But I agree with the possible causes.

 

Just bumping the thread.

This problem is so curious, I'm hoping the OP returns to let us know what eventually was discovered.