sluday

Can someone explain how the tire pressure monitor works? If I switch the tires to snow tires with different rims, does it still work?

sluday

I read that it is a sensor in the valve stem. I also heard that some cars have sensors in the rims. Which one does the TSX use?

n8dog82

the TSX has a fairly large sensor on the inside of the valve stem which communicates wirelessly to a computer in the car..

Simba91102

There doesn't seem to be too much here (this forum) on the TPMS experience. IMHO it's more of a gimmick than anything else, but I check tire pressures regularly (though I know I'm in a huge minority). I fear that in a traumatic failure situation, it's worth about as much as the depth finder in my boat; basically it will tell me how far down the rock was that I just hit. That said, I plan on running snow treads on non TPMS equipped wheels (this is on my wife's 07 TSX) so I performed a little experiment. I put a couple of the OE wheels (from storage off my 05) on her car and took it for a ride. Surprisingly, the computer didn't seem to realize that the TPMS equipped wheels were missing. Maybe I didn't go far enough, or maybe there's a delay, or maybe it wasn't working. Anyway, as far as I'm concerned it was good news. There was one thread on this a while back and it seems you may get a warning at startup on the display, but you can acknowledge it, scroll past it and that's it. That's my input; I'd be happy to see more on this from someone with more experience on running non TPMS equipped wheels.

Tex929rr

I think you nailed it right there. Most people don't check their tire pressures. TPMS will be required on all new vehicles soon - I think if it warns someone when the tire pressure on their vehicle drops to a dangerous level that's a good thing. It may have saved a lot of those people driving around with underinflated tires on their Explorers a few years back.

Some TPMS work better - GM's had them for a while. The one on my vette reads actual pressure on each tire and is one of the display items you can call up. I assumed the TSX would work this way and was disappointed when I realized how it worked. I even get a monthly e-mail from Onstar where it reads the engine diagnostics and reports results as well as tire pressures for each tire.

On the GM system each monitor is dedicated to a certain position - often guys complain on the online forums about tire places switching the wheels and then the readout is wrong.

Daffunda

It is a direct TPMS, which measures the actual tire pressures. The sensor is integrated with the valve stem. With indirect TPMS, you don't have to, since all it does is measure wheel speed with relative to the others. So if you get a new rim, you would have to swap out the TPMS unless you want that annoying warning.

mrgold35

The way I understood the TSX TPMS is you have four independent sensors integrated into the value steam of each tire. Even if you rotate your tires, the system is smart enough to read the correct pressure from the tires in the new positions.

The sensors measures the PSI inside the tire compared to a tire gauge that measures the tire pressure in direct relationship to the outside air pressure. Acura's TPMS will result in more accurate readings overall compared to the best after market tire gauge. After market gauges would be more affected by altitude, air pressure, humidity, and temperature differences during morning/afternoon/night compared to the TPMS.

black label

Apparently you have never hit the select button on your TSX when you were on the screen that says "tire pressure OK", if you had, you would already know that it will display exact actual pressures in each wheel.

Acura uses a "direct system" which monitors actual pressure in the tire.

The problems with a direct system are:
1)it is more expensive
2)it can limit your aftermarket wheel options

The alternative would be an "indirect system" which uses the ABS brake computer to moniter how many times each wheel spins per mile. If one tire is low on air, its circumference will be smaller than the properly inflated tires therefore it will spin more times per mile and send off a warning light.

The problems with an indirect system are:
1)it cannot tell you which tire is low on air
2)if you are losing air out of all tires at an equal pace (all tires lose air slowly even brand new ones) say 1psi every 2 months, in 1 year you are 6psi light in each wheel (26 psi is NOT GOOD b/c at that point you are driving on your sidewall) and the system will be blind to the problem as all 4 wheels still spin at the same rate.

Tex929rr

Nope - I'll try that today.

WhiteDragon07

iTrader: (1)

Just thought I'd resurrect this thread with some news.

Just had a set of Blizzak WS-60s (205/60R16) and alloy wheels installed on my car this weekend. When I realized the place hadn't switched my TPMS sensors from the all-seasons to the winters (after buying winter tires, couldn't afford a new TPMS!), I made arrangements to bring the car back the next morning to have them transfer the sensors.

But then I realized... "tire pressure OK" still displayed. We thought at first it was a case of really good wireless communication between the car and the sensors on the wheels still in the trunk! So we removed the wheels and I drove away, and tire pressure was still OK. So I opted not to transfer the TPMS and put the winter tires in storage...

Only to get to work this morning to have "Check TPMS system" appear on the MID. But it doesn't beep constantly, so I think I'll just deal with the "i" light on the MID this winter, and hopefully next winter have enough $$$ to afford a new set of sensors for my winter tires! I'm good about checking tires anyway since I travel a lot, and I can usually tell when a tire is even a couple of pounds below normal.

Just my

xjohnkdoex

iTrader: (2)

while it is gimmicky, it was useful when i had a slow leak.

sometimes i scroll through just to see what it says for my tire pressure. one day i noticed that one of my tires was notable lower than the rest. i refilled the tire w/ air, and after a few days, saw on the tpms that it was low again. i verified that there was a leak thanks to the tpms and a standard pressure gauge that i keep in the car also.

so it's more of a convenience feature. but i wouldn't live and die by it, and if i lost it, i wouldn't be too heartbroken.

Mskierki

The pressure in your tires is directly related to the atmospheric pressure/altitude. Also, the temperature differences based on the time of day are minute compared to the thermal variation caused by driving on them.

It sounds like an cool feature, but I would still use the gage.

litesout

Okay, going to try and bring this thread back from the dead. I have an 08, so it has the TPMS. My question is, when I rotate my tires, do I need to do anything to reset the tire positions? I know the GM system is pretty involved, requiring you to either inflate or deflate the tires in a specific order (noted by the coresponding parking light for that corner coming on) until it blasts the horn. When you put the system into the reset mode it looks for the change in pressure at the one tire and assigns that wheel to that position. The procedure is well documented in the owner's manual (at least in the Impalla it is.) I found no such procedure for the TSX.

So, I guess I have two questions then. First, how does the system know which wheel is at which corner? And second, do you need to reset that data when you rotate your tires?

DLTSX6MT

"does the system know which wheel is at which corner?"
Yes.

"do you need to reset that data when you rotate your tires"
No.

litesout

I figured it knew which wheel was at which at which corner. I'm wondering how it knows, and how it knows to reset that data when the tires are rotated.

datadr

I'm certainly no "TPMS guru", but my guess is that the receiver for each tire is located at the wheel itself - possible part of the ABS system. Anyway. When you move the wheel to another corner, the receiver at that corner just picks up the local sensor. The sensors must be pretty close to the TPMS transmitter in the tire. Short distance radio xmit, and I mean short (12" or less) doesn't put much strain on the battery in the TPMS tire sensor.

That brings another question up - if the TPMS system is wireless, then how long will the sensors last in each tire, and are the batteries user replaceable or does the entire sensor get replaced?