Yeah, what can I say. Did not feel too smart. One of my wheels has been loosing about 6 pounds a week for a month or two but I had not taken it in to have them sand the bead to re-seal the rim. You know, the infamous leakage with 12 year old chrome plated aluminum rims. Procrastination...

Anyway, I was getting a pretty hard pull to the left but it did not dawn on me to check the tire pressure as I just did a few days before after I returned from a trip. It was a bit down at 28 psi. I keep a nice little portable pump in my car. Refilled to 34 psi. Not sure what happened but the tire deflated to about 12 psi and I was driving around for 2 days this way in crazy NYC traffic...

What is disappointing is how pointless the tps system is. It never turns on if I have low pressure. Only if I rotate my tires. Rim is fixed for now but I have a feeling new rims will be needed to totally fix the issue.

Funny, I even called the local Toyota dealer to schedule a check of my alignment as they were the last shop to do an alignment after replacing inner and outer tie rod ends. I thought something loosened and the alignment was off.

 

Wow...that's crazy the TPMS didn't light up. Are the TPMS working? Sounds like that one sensor may be dead.

 

The system in the 430 is based on the wheel speed sensor and revolutions. It triggers no problem if I rotate my tires but not when the tire was at 12 psi. Yeah, it's pretty useless.

 

TPMS is part of ABS system on the LS so its constantly active comparing wheel rotation to detect any lockup/slide on any of the wheel(s). If the ABS system isn't getting data from a wheel it will immediately fault and deactivate the ABS system. It does seem strange that one tire was down to 12 psi (which should change diameter pretty significantly) without throwing a low pressure warning on the TPMS. Suggest you get all tires up to recommended pressure and reinitialize the system so it has a new base data point on all tire diameters going forward.

 

I'll try to re-initialize the system. It is odd. As I mentioned, when I rotate it does trigger the system. ABS essentially is the wheel speed sensors.

 

When the LS is in motion the ABS reports instantaneous tire rotation speed for each tire/wheel along with current mph speed data to the TPMS. The TPMS divides each tire's rotation speed into current MPH speed to come up with a number that represents each tire's current diameter. The TPSM system compares that instantaneous calculated diameter number to the diameter numbers stored in its base line data set created when the system was last initialized. The system works because a tire that has lost pressure since the system was initialized with that tire at full pressure will have a higher rotation number because that tire is smaller in diameter and now has a greater rate of rotation per given mph speed than when it was at full pressure (and had slightly larger diameter). The system is sensitive to small changes so it is common for it to fault when tires are rotated as now none of the tires match the base initialized settings because of minor variance in tire pressure and size. Hopefully it is clear that it is critical to initialize the system when all 4 tires are in good shape and at full pressure.

 

Something seems wrong. I've had one wheel low and it triggers immediately. Problem is when you have them all dropping at same time, and then TPMS senses no tires are rotating faster/slower than others. One bad one should have triggered.

 

I have battery operated sensors on my 014 TDI, each wheel has its own. Great safety feature.

I had a nail in my pass rear couple years ago on my LS.. Sensor went on just north of 20 lbs and it alerted me so I was able to get it patched and not be stranded.

 

The WRX also has tpms sensors at each wheel. I believe by law all newer vehicles have to have it.

My system has never alerted me when a tire is 5 - 10 pounds low. At 20lbs low you would think it would. If I remember correctly the system takes about 25 miles to calculate the warning.

Like when I lost a front tire at 75 mph on the highway. The system triggered 30 min after I put the spare tire on...

 

Interesting. Had the same experience with a puncture (at about 40 mph) on right front tire on one of my '06's. Tire deflated quickly. I drove on it flat to the nearby Lexus dealer (they changed it complimentary). The TPMS warning never came on. I check my air pressure every couple weeks anyway and don't rely on the TPMS system. My '09 Sienna has the inflation sensors at each wheel.

 

I think in 07 or so is when they started putting in sensors at each wheel. I like the systems that actually tell you the pressure at each tire. Most cars don't have this. I have had to do the bead sanding procedure for all 4 wheels so far. Maybe new rims are in order next summer.

Loosing a front tire at 75 mph was not pleasant. A piece of metal or something cut a 3 inch hole in the sidewall. Went flat in less then 8 seconds.

 

Ouch, glad yur ok Lav.. Nobody is gonna ride me on getting a dieselgate Touareg? She is a torquey lil devil.

 

Lav, you are experiencing the environmental hazards of driving in the northern (and congested) states.

 

I have somewhat had the same issue. I have reinitialized a couple of times when one of my tires has gone low, but never got an indicator of low tire pressure. Recently one of my tires was down to 20 pounds and I never received the low indicator light. I have been watching my tires recently just to be cautious.

 

Atlanta had pretty bad traffic as well but the roads are in much better condition. This will be my first year living in a state that gets a good amount of snow. Have the snow tires and wheels ready and I'm considering some kind of underbody coating.

The tire incident happened about 8 months ago near the Atlanta airport.