Rich

I was at my dealer's new-car-owner party the other night (more about that later in another post) and one of the things mentioned by the service staff is that TP monitor. According to them, it goes on when any tire differs from the others by more than 2 to 2.5 psi. The subject was brought up because a few of the attendees (not me) remarked about this light being lit when they arrived.

The service manager went on to explain that in cold weather (it was about freezing) the spare tire often sets off the monitor because it is not being heated by the road surfaces. Well okay, I guess that made some sense.

However, mine lit up yesterday morning while I was driving (about 22 degrees- it's cold here). I checked the tire pressures anyway and all four were at the prescribed 33psi. When the day finally warmed up, the monitor light disappeared. But then in my owner manual I read that the button spare is at 60psi. So how does that relate to the service manager's remarks??

I have a feeling this monitor is gonna be a pain in the butt for both owner and dealer.

Djicey702

The button spare? I think I know what you mean, lol I would check the spare tire pressure, and then in the morning before you drive the car, check and see what the tire pressure is on all four tires. If your spare has 60psi and your other tires have at least 32psi I would reset the TPWS, and if non of that works, have fun at the dealership.

SLODEANIS

The spare tire is not monitored on the xD, only the 4 main tires. The spare has a normal $0.50 tire stem.

Rich

So if that's the case, do you have an idea as to why the monitor is set off in cold weather? I either misunderstood the service manager's remarks (entirely possible) or he doesn't understand the problem himself, or he just didn't explain it very well. All I know for certain is that it's some kind of false reading, and that I'm not the only one affected.

SLODEANIS

I would imagine it is just a temperature related issue...I live in CO and have had some cold mornings already, but my TPMS has been working fine. It is entirely possible when you had your alloys installed the dealer did not reinitialize the TPMS system...I did it myself when I had my alloys installed. I would just make sure the tire pressures are OK, then reset it to "learn" the new pressures.

As for the spare tire monitoring, some Toyotas and I believe all Lexus models monitor the spare tire. All Scion and some Toyotas only montitor the 4 regular tires. It's weird I know....Also, I believe all Lexus models can hold up to 10 TPMS sensor ID's as there is a button for "Second Set" in case you have snow tires. The rest of us have to go to the dealer and have it reprogrammed. It's upsetting, but that's what you get when you buy one of the least expensive products Toyota makes.

Rich

Slodeanis, thanks for the info; and I'll bet that your analysis of the problem is correct. Are instructions for resetting the TPM in the owner's manual? I didn't notice it the other day when reading the manual. It's my wife's car and I'm at work.

SLODEANIS

Yes, it's in the manual. It's really simple. Just turn the car on, press and hold the TPMS button just under the steering column and to the left until the TPMS warning light on the dash flashes 3 times. When the light starts to flash, let go of the button and that's it. The TPMS computer will then memorize the new readings. No need to drive around or anything like that. It's instant. Hope that helps.

Rich

Thanks for the help- I'll do that.

zoltiz

The only time mine was set off was when I parked one side to the sun - took about 5 miles for the thing to level out and the light was gone.

offroadinfrontier

i had this on my last 3 vehicles - if the weather is cold, it probably isn't an issue. if the system is working properly and you drive for a mile or two, the light should go off. if it doesn't, then you need some air.

as far as the spare monitor, i've never heard of a car that can monitor the spare tire, even if it has the sensor in it. from what ive read, the tires have to rotate to power the transmitters, and after driving a bit of power is stored so the active sensors can monitor the tires at startup, but only those that were spinning before the car was shut off.

the system might be different on Toyotas, but that's how my system worked on my two Nissans.

Rich

Now I'm really confused- if (as the service manager told me) the TPM lights when it detects a 'difference' in air pressure on one tire, why should tire pressures all be equal again by simply driving a mile or two? Also, it seems to be an issue when the weather *IS* cold. Tomorrow, I will try Slodeanis' suggestion and reset the TPMS. I'll report back with the results after living with it for a couple days.

offroadinfrontier

What?? The TPM light comes on when ANY tire is underinflated. When it is cold outside, the TPM light will most likely activate for a few seconds (and up to 2 miles) before going off. Who said anything about the pressure being equal after driving a mile or two?

Translation: When it's cold, the light will go off after 1-2 miles IF your tire pressure is fine AND your TPMS is set up properly. This = normal.

Cold+Good PSI=Light on for 1-2 miles
Any Temp+Good PSI=No Light
Any Temp+Bad PSI (in ANY tire)=Light on until problem fixed & driven for 1-2 miles

Rich

The problem is that you and I seem to be separated by a common language.........:-)
I think I understand you now, but although the light finally does shut off, it's taking longer than two miles. And yes, the pressure in all four tires is at 33psi. And I'll remind you that my original post stated that the service manager said "it goes on when any tire differs from the others by more than 2 to 2.5 psi."

I do believe we've exhausted the subject though- so thanks for the help.

zoltiz

The difference in pressure situation was true for older ABS-based tire pressure monitors (no individual sensors inside the wheel). Current generation monitors actual tire pressure instead of wheel speed to determined possible flat, so that statement by the service advisor is about 4-5 years too late.

Rich

zoltiz.....
The definitive answer to my original question That (plus all the help from others here) settles it. Many Thanx!

offroadinfrontier

So much for reliable service manager information.. I bet we could fill up 3-4 pages of a thread just on incorrect information given by service men. I've got a huge list from my two Nissans alone ::rolls eyes::

jatkins44

mine did the same thing today. i actually got on here to see if anyone else had the same problem.

when i started my car this morning, it stayed on all the way until i got to work. when i left at lunch it came on again, when i left after work, it was off. it was only like 75 degrees this morning when i left home. that's cold for phoenix, but not cold to most people.

it bothers me that it is that touchy. i don't know if i should believe it or not.

offroadinfrontier

it can be very frustrating, especially when its cold AND your tire pressure is low, since you learn to ignore it. But don't blame Toyota - US law is making these mandatory in a year or so, and I doubt making them any more precise can be done without noticeably affecting a car's price..

jatkins44

i just want everything on my two-month-old car to work right...that's all

just an opinion-the light contradicts itself & i don't like that

offroadinfrontier

what i'd like to see are more precise sensors and some type of display that lists each tire's PSI. I know a few luxo-cars have these, but that's with their included LCDs and what not.

I could see an easy, cheap adaptation for just a few bucks taht integrated with the trip and mpg led setup - press a few more times and it displays FL - 30.1PSI, FR - 30.2PSI, etc. When the indicator flashes, it could pop up the tire that's low (FR - 24.5PSI).

Maybe some additional programming to keep the light inactive until the tires warm up if the temp is at xx deg.

IDK about anyone else, but I'd pay an extra 50-100 bucks for that feature. Then again, I'm the kinda guy who buys a scanner (scangaugeII) to see my check engine lights... I hate generic warnings that could mean 20,000 different things.