Tire Pressure Warning System Reset Switch -- Can't Find

[crcr]

Hi, I have a 2004 Highlander. Today the Low Tire Pressure Warning Light came on. I checked all my tire pressures, and they are all even, so I'm not sure why it came on. I did put new tires on about 2000 miles ago, and am carrying a higher pressure than before -- 40# vs about 32# before, so perhaps, but this is the first time the light has come on.

At any rate, for now I just need to try resetting the Tire Pressure Warning System, so I looked in the Owners Manual, and it told how to do it, and showed a picture of the switch, which is below, but I cannot find that switch on my Highlander. It appears to me in the illustration that the switch is in the lower part of the dash. Anyone have any tips on why I am not finding the switch on my Highlander, and where to find it?

[O8HLLTD]

When my TPMS went off, it turned out to be the spare. I had checked all four and they were fine, but didn't even think about the spare. Just a thought.

[05Moose]

First of all, the TPMS light will stop showing when the tire pressure is above a preset level. Thus, check the air pressure in all your tires first. Using the reset switch will set that preset level to the pressure you have in the tires at the time you press the button. In other words, if you have 35 psi in each of the 5 tires, then reset it using the switch, it will trigger the warning light when you drop 2 psi below that 35. Conversely, the same is true if you set it when your tires are already low on air. So only use the reset switch when you've got all 5 tires set to the proper pressure.

As stated above, check the pressure in your spare tire! There are 5 tires with sensors.

If you still want to find the switch anyway, you won't see it from the driver's seat or from standing outside the vehicle. Get down there and look as if you're going to look up behind the dash and you'll see it on the lower part of the dash. It sits in a little indentation of the dash plastic.

[bepperb]

An 04 Highlander does not have a sensor in each wheel or the spare. It does not know how much pressure is in each tire. Other cars do, this doesn't. So the above two posts don't apply to your vehicle. Actually, Moose is right on with the location of the button, which is hard to find.

Instead, you car uses the ABS computer to compare the rotations of the four tires touching the ground, and if there is a significant variance it will trigger the light assuming one or more are low and thus have a smaller rolling diameter. To accomodate tire wear, there is a button that will reset the computer to tell it "the tires are all full now", so whatever the ratio is of rotations between them is correct. It was probably calibrated to your old tires and needs to be recalibrated now. The button isn't hard to find, but that illustration isn't a good one. If you can find the OBD-II connector, it's right there. It's at the very bottom of the dash, closer to the pedals than the steering wheel.

Why are you running 40psi? That's much higher than what's on your door jamb, and while a bit higher can give better fuel economy that's so high it's got to be giving you a stiff ride.

[05Moose]

Originally Posted by bepperb

An 04 Highlander does not have a sensor in each wheel or the spare. It does not know how much pressure is in each tire. Other cars do, this doesn't. So the above two posts don't apply to your vehicle. Actually, Moose is right on with the location of the button, which is hard to find.

Instead, you car uses the ABS computer to compare the rotations of the four tires touching the ground, and if there is a significant variance it will trigger the light assuming one or more are low and thus have a smaller rolling diameter.

They changed that in '05? We've got them in our tires in the '05 HL (non-limited V6). In fact, we had a problem once where it kept tripping. It eventually fixed itself, but the dealership was going to pull each wheel to see which sensor it was. They said the computer logs the sensor number sending the signal, but to figure out which sensor you have to remove the tire from each wheel to read the number on the sensor itself until you find the right one.

So I can then assume that's a change between the '04 and earlier highlanders compared to the '05 and up?

[bepperb]

It may be a change for '05. The refresh was in 04, but several things didn't get implemented until 05. I know my 04 doesn't need a transponder key, but all 05's do, a direct TPMS may have come then.

This link explains, and says until '06, but the HL's may have been a mix for a few years:

Indirect Tire Pressure Monitoring Systems: The TPMS System That Knows The...

Here's and excerpt the OP might use:

On Toyota applications, the reset procedure is fairly straightforward, though it actually takes much longer to complete. Turn the key on (engine off), then press and hold the RESET button until the flashing TPMS warning light goes off. Or, if it is not flashing, hold the RESET button until the light flashes three times. Turn the key off. But the relearn procedure is not complete until the vehicle is driven at 19 mph or faster for at least an hour. You don’t have to do this, obviously, but your customer should be made aware of the fact that the TPMS reset procedure won’t be complete until the car has been driven awhile. During this time, the TPMS system may not be able to detect a low tire, so make sure all the tires have been inflated to the correct pressure before the vehicle leaves your shop. In our October issue, we’ll cover some reset procedures for direct TPMS systems.

[05Moose]

Good to know. Maybe the dealership didn't know what they were talking about in our case? Although my dealership usually has pretty knowledgeable people working there, but one never knows.

[crcr]

Thanks to all! I did finally find the Tire Pressure Sensing Reset Switch. As someone correctly pointed out, the illustration is not accurate. You almost have to lay your head on the floorboard to see the switch.

I did check my spare tire -- thanx for that tip -- it was the one that was low and apparently set off the sensor. So I have refilled the spare, but haven't put it back up in place yet -- want to watch it for a couple of days to make sure that it doesn't have a slow leak before I remount it in the rear undercarriage and reset the tire sensors.

As to why I am running 40# pressure -- When I replaced the tires 2000 miles ago, and then got a fresh front and rear tire alignment, my longtime tire alignment shop owner recommended to me to run 40# in these tires. I am running BF Goodrich Long Trail T/A Tour tires. This is a newer tire and a completely different tire than the old Long Trail tire. At any rate, my alignment shop, which has the best and decades long reputation of any alignment shop in the area (that has been my longtime experience as well, and therefore I trust them) told me that the rubber of Goodrich tires is particularly soft, and recommended I run 40# in them, if the ride didn't bother me, both for the benefit of better tire wear, and better gas mileage. The stated max PSI on the tire is 44#, so I am well under that. When I first got the tires, I could tell immediately from driving them that the rubber felt a bit soft, plus my gas mileage definitely dropped off noticeably from the worn out Goodyear Integrity tires that I took off of my Highlander. I have noticed a slightly harsher ride increasing from the 32# the installer put in the tires, up to 40#, as would be expected, but not as much as I expected, and it's definitely not unacceptable or objectionably so, not even to my wife, and we all know the ladies are probably more sensitive to the ride quality than us guys. And these new Goodrich tires definitely ride smoother at 40 psi than the old Goodyear Integrity tires did at 32 psi. So for now, I'm going to stick with the 40# that my alignment guy recommended. It's too early to tell yet if the gas mileage has iimproved, or how much, since increasing from 32 to 40 PSI.