Tire Pressure LIght issues?

Is anyone having issues with the tire pressure light? On my new (< 2000 miles) Gen III, the tire pressure light has come on flashing - indicating there is a problem with the system, not just tire pressure. After about 25 minutes, it goes off. Took it to the dealer once and they didn't find anything wrong (the light wasn't on at the time) and they told me they just added air to the tires.

It seems to happen to me early in the morning - I leave for work at 5:30 AM. After about 15-20 minutes driving, it starts flashing, then goes off after another 20-25 minutes. Since it's flashing, it's thinking it's not related to tire pressure and/or temperature.

Two days ago, the same thing happened in my wife's new Prius. Her's came on in the afternoon though, on the way home from work.

In both vehicles, turning the car off, then on again, makes the light go away.

 

Well, given that the light was flashing, which indicates a system problem, and not on steady, which indicates a tire pressure issue, I did not try resetting the TPMS. That's my next step, but thought I'd ask here first.

 

Good point. Both were purchased from the same dealer, although one was shipped from another dealer a ways away. Still, I'll have them re-initialize the system next time I bring the car in.

 

I'm 99% sure I found the problem. Page 444 of the owners manual states: "If the ID code of the tire pressure warning valve and transmitter is not registered, the tire pressure warning system will not work properly. After driving for about 20 minutes, the tire pressure warning light comes on after blinking for 1 minute to indicate a system malfunction."

This is exactly the behavior I am seeing. I'm dropping it off at the dealer Saturday to get it fixed.

 

Took it back to the dealer yesterday. They checked the error codes, reset the codes, and re-initialized the system. Said they left the car on for over 30 minutes and the light did not come on. The real test will be when I drive it to work tomorrow.

 

Sad to say, but my tire pressure light came on again this mornign :-( Same behavior as before I took it to the dealer.

 

It wasn't a tire pressure issue. The light came on after 20 minutes of driving and it was flashing. This indicates a problem with the montioring system, not a tire pressure issue, per the manual. The behavior I was seeing was described EXACTLY on page 444 of the manual, where it describes how the system behaves when it has not been initialized.

I have not seen the light come on again, so perhaps it was finally fixed.

 

An update: I've been having this problem on and off since I first got the car - almost 18,000 miles ago. It's been back to the dealer 7 times to get fixed. On the eight time, after filing a complaint to get the car replaced under my state's lemon laws, they discovered the problem: Interference with the tire pressure sensor signals from the LEDs I used to replace the license plate lights. More details in this post. Just wanted to get this out there for future reference. I never would have suspected LEDs could cause interference with RF signals (and I'm an electrical engineer), but apparently they can.

 

They replaced the tire pressure computer in my car too, but that didn't fix it. Would be interested to know if you replaced the license plate bulbs with LEDs. That was the cause of my problem.

 

As an FYI, Toyota also investigated a couple other areas with me: 1) window tint. I have ceramic window tint, so that wouldn't interfere with RF signals, but if you use metallic tint, it might. 2) Cell phone charger - plugs into electrical system. A cheapo model might send feedback into the electrical system. 3) my daily commute - did I drive by any high-power radio or cell antennas. (Personally, I think they were grasping at straws with this one.) Basically, check your car for anything you might have added that could block radio signals or that connects to the electrical system (which could cause feedback).

Since your light is flashing, it's not a tire pressure issue, so resetting the system won't do anything. It's a system issue. Can you determine any pattern to when it happens (other than after 20 minutes)? For instance, is it only happening when your lights are on? When it's below or above a certain temperature? When you are in a certain part of town?

I was also getting very frustrated, but just be patient. Toyota really was fantastic with me. Check your state's lemon laws. In Arizona, you have to give the dealer 3 or 4 chances to fix it. If they can't, then you can file a claim. Actually, there is a handbook that comes with your manual that details what to do if you want to file a claim. Forome states, like Arizona, Toyota requires that you file an arbitration request first. The nice thing is that the arbitration results are binding on Toyota, but not you, so if you don't like the results, you can still go to court for a new car. But I would recommend going down that route. It gets their attention and it's no cost or harm to you.

Document every time you've taken the car in to get this repaired. Use https://auth2.toyota.com/owners/apps/mytoyota/auth/ssl/OwnersLogin.do. This will let you access the dealer's records for you car. I used the info from here when I filed my arbitration claim to document repair attempts.