I've had my prius since April and the tire pressure light keeps coming on. It's been in to the dealer 5 times now and they have yet to find out what's causing it. It doesn't come on when I'm driving in town but only when I'm going out of town on a trip. I make almost monthly trips that are approximately 180 miles one way. I don't go over any mountain chains or have any large increase/decrease in temperature. I've been documenting when it comes on and it seems to be about 1 1/2 hrs into our trip but it has come on earlier also. Basically, the light will come on, start blinking for several seconds and then stay on until the car is stopped. Then it'll turn off. However, I've also had it only stay on for a few minutes before it turned off. It's never on when I take it in to be looked at. The technicians at first checked the tire pressure and then reset the sensor. Then on the 2nd and 3rd visits they "woke up" the sensor and reset it again. On the 4th visit they decided it was time to change out the TPWS. Unfortunately, it's still coming on. I was in there yesterday and now they want to rip off the tint film that they had installed at their authorized window tint dealer. The first person I talked to said it was the metal flakes in the tint but the tint has no metal flakes, I checked. It's Llumar ATC35 film that is a "dyed polyester" per the technician at the shop where it was done. Now they're saying it's just too dark and that it's interfering with the sensors. Again, the light does not come on in town, just on semi long trips. Any thoughts?
Sorry to hear of your troubles but how is it that window tint interferes with a tire pressure sensor?
Just some idle thoughts, no real help with your core issue: I understand Tire Pressure Monitors are legislated, ie: you have to have them, at least, a new vehicle being sold has to. I think you're ok to remove them, or just swap in new tires without them. We got snows on separate rims without sensors, just after getting our Prius, and apart from a little light on the dash, no problems. It was a dealership install, so it looks like they're not forced to install TPM's. Tire Pressure Monitors are a commendable idea, I guess, but when they are the problem, very frustrating.
It'd be nice if you had a laptop with TechStream installed, so when the light came on you could try to figure out which sensor is causing the light to come on. Considering you've been there a few times for the problem, if they can't identify the sensor, I would push for them to replace all 4 under warranty and see if that fixed the problem. Maybe a call to Toyota Customer Care is in order. I know it's not a necessary part of the car to run, but as Mendel said, very frustrating.
I took a small piece of black electricians tape and placed it between my eyes and the tire pressure warning symbol (summer wheels), problem solved. You may find yourself qualifying for the lemon law clause, but I'd go to a different mechanic (dealer) before I wasted any more time.
Try following the initialization procedure in the attached service bulletin. It is possible that the techs just aren't doing it right, i.e. leaving in Ig-On for 5 minutes then turning off, after resetting. Mods, this should be in a Gen III forum.
I see where the TSB is listed for the MY 2011. Does this apply to the 2010 or is the TPMS different in the 2011?
Not sure if 10 and 11 are different. Kimo, the tint suggestion is related possible sources of interference described in the service manual. I doubt that it is the tint, but it could be interference from something else. Do you notice that you have the problem in a particular area of your long drive? Do you use a radio transmitter of any sort, such as Bluetooth or an MP3 player transmitter to a particular FM frequency on the car radio?
Common problem on Gen 2s: Have a good tire technician check the way your tires bead with the steel wheel rim. If the rims are cleaned and treated with the correct light adhesive the tires will comply with more confidence and it will abate your problem. I have this problem on occasion with my 2007 and 2009 hatchbacks. Fantastic cars. Annoying recurrent problem. Check your valves, too. You will especially see this with the first cold weather of winter when all the tires will lower in pressure. Give this idea a try. It may help.
