mrtnd0000

I am looking thru some of the features on the new RX and am stumped on one particular part - maybe some of you guys can help.

The driver information (message center or what have you) / small screen in between the gauges that you can pull up information on has the option to display the current tire pressure.

While looking at it, i noticed that it simply lists the current tire pressures in a rather vague fashion.

ex: 36psi 36psi 36psi 36psi

All though this is all well and good, the message center fails to actually provide a way to determine which of those tire pressures goes with which actual tire.

(i assume that from left to right the tire pressures are left front, right front, left rear, right rear)

but as a lexus employee (product specialist) i do not have room for assumption and must have an exact answer!!

if anybody has more information on this minor feature - please share !!!

thank you

Matt

ggebhardt

The exact answer is you guess as they are in no particular order except which one registered with the system first when you started the vehicle last. A lower pressure tire can be at the top of the list one day and thrid on the list the next day.

Just check their inflation ever few weeks and if you find them not loosing any iar, I would increase the time between checks.

mrtnd0000

Thanks for the quick reply.

Is there a way to re-register the order by yourself ?

jrfiero

ggebhardt, do you have a source or documentation for this statement?
"no particular order except which one registered with the system first when you started the vehicle last. A lower pressure tire can be at the top of the list one day and thrid on the list the next day."

I don't think that's true on my '13 450h. Through experimentation mine read RR, LR, RF, LF, and they stay consistent. I set my tire pressure with a gauge I trust as more accurate than the dash display, and I increase rear pressure when towing. Rears always stay at the first two positions, and I've proven to myself when changing pressure which side is which.

I don't know how it originally "registered," but mine stays in the same order. I'm sure it will change at the next rotation and I'll have to figure it out again.

Jonas

mrtnd0000

Jonas,

Thank you for chiming in on this matter. Myself and my co-worker were debating on whether we should just start fiddling with the air in the tires to see for ourselves, but assuming that the TPMS hasn't really changed from 2013 to 2014 we shouldn't have to.

If we do get a sure answer I will be sure to post.

Matt

kitlz

With the way the tire pressure displays randomly upon startup, it almost seems like it could be in the same order. I haven't experimented but when I had the spare on, it was in the same spot from one day to the next. It's too cold to try right now so I'll be interested to see what others find out.

seanlin

Mine was RR LR RF LF.
After I rotated the tire at 5K miles. It is now RF LF RR LR. So confusing.

mrtnd0000

ok so i just talked to one of our service guys here at the dealership. he explained to me that there is an individual sensor just behind the valve of each tire.

when all four tires are mounted - service has a tool to calibrate them and determine which is which.

when all four tires are mounted - YOU have no way of knowing how they are calibrated until you start messing with the tire pressure.

when your tires get switched around, the reason why the numbers are constantly getting messed up is because of the individual sensors in the tires and the only way to figure out what the order is would be to consult with your service adviser after they calibrate the order.

quite frankly, i feel that there should be a little bit better of a way for the car to measure the tire pressure, perhaps having a fixed monitor on each corner that can match up with whatever tire is mounted and somehow read the pressure from there. although it may be a bit complicated, having an individual code for each tire despite what corner it is mounted on is equally complicated ( to me at least )

I'm going to continue to try to figure out this TPMS design (flaw?) but for now thats all i got.

matt

rajudv

I dont see an option on my 2011 RX450H to display the Tire Pressure Information. Is this some kind of an upgrade ?

mrtnd0000

should be on the message info center (small screen in between the RPM and MPH gauges)

perhaps with the older models its not there - im surrounded by 2014 models here at the dealership so dont have much to compare it to.

however, with the controls on the steering wheel you should be able to cycle thru a few menu options including the tire pressures.

MrBBQ

iTrader: (9)

I have wondered too what tire order are the TPMS readouts. Having 4 tire pressures in a straight line doesn't say much. At least it's something to look at from time to time to make sure the tire pressures are in check. I had a 2IS that didn't even have a tire pressure readout. You just get a low tire pressure warning and still you don't know which tire it is. Coming from this, I'm grateful the RX have a pressure readout. As long as all pressures are in check, I don't care about the order. However, I am getting spoiled by my 4GS that I just picked up and it has a picture of the car with the tire pressure on each corner for the TPMS readout.

gotin

Every sensor has an unique ID# which must be programmed into the memory of the TPMS.
You can store up to 5 TPMS sensor ID# in the memory of the RX450h. Example:
Registered ID 1 Code 082713B
Registered ID 2 Code 0827130
Registered ID 3 Code 0827131
Registered ID 4 Code 0827182
Registered ID 5 Code

They will always appear in the same order on the screen - ID 1, 2 ...
When I bough the car, the ordered was RR LR RF LF.
This means that the sensor with ID 082713B is installed in your Right Rear tire,
0827130 in your Left Rear and so on.
The sensor which ID# is programmed as ID 1, will always appear as first on the screen no matter where it is installed.
You must keep track which sensor goes where by tire rotation or summer/winter tire exchange. For example if you exchange left front with left rear and right front with right rear then you will have RF, LF, RR, LR on your screen.
In fact there are 4 possibilities:
1. You must always keep track how you exchange tires and "update" a piece of paper with the current order.
2. You must visit a LEXUS dealer for reprogramming the order of the sensors, so that you always have the same order RR LR RF LF on the screen after every tire exchange.
3. You must play with the pressure of every tire after exchange and find out which tire where goes on the screen and write the order on a piece of paper.
4. You will loose track of the exact position of the sensors and the order of the screen will mean nothing.

If you by a second set of rims and original sensors for your winter tires you must visit a LEXUS dealer after every tire exchange for ID# reprogramming because there is no place for 8 sensors in the memory! Or you must buy intelligent sensors with programmable ID# and the second set must be programed with the same ID# like the first one.

Sounds really confusing and this one of the RX450h features that I personally do not like at all. The TPMS sensor programing and visualization could and should be done much more intelligently by a high-performance luxury SUV.

My experience is with European vehicles but I suppose, that it is the same with American ones.

mrtnd0000

Wow this last post was extremely helpful and SPOT ON.

Thank you for sharing all of this with us as it is a very helpful explanation to what has been a rather confusing/complex design "flaw" in the new lexus RXh.

Hopefully in the future lexus will recognize this and include a more sophistocated display of the tire pressures similar to the ones in some of the other models like the LS and the GS etc...

Thanks again,
Matt

websailor

Agree with it should be better.

If you really wanted to I think you could figure out what the sequence is by picking a tire, inflating it (or deflating it) by say 5 psi more, then looking at the display to see which tire it is in sequence. Write that down, then repeat on the next tire, etc. Then set all the tires back to the pressure you should be running them at. Kinda a PITA if you ask me!

Ernie

gotin

This exactly what I have done (deflating tires) and what I mean in:
3. You must play with the pressure of every tire after exchange and find out which tire where goes on the screen and write the order on a piece of paper.

You explained it much better then me.