The tire pressure warnings puts the message in the system display area .Lists Tire Pressure Low and 5 pressures: after adjusting the LF,RF,LR and RR , pressure shows the slight increase in all 4 , so I'm deducing the spare is at the top of the list ... It is the culprit .. Looked thru the Encyclopaedia L460 and found nothing specific . Would be useful if it listed which tire along w/ the pressures, or am I missing something else ?? Thanks ..

 

Spare
LR
RR
RF
LF

I stand corrected.

 

The order is not defined, and the order on the screen changes whenever a tire is moved to another position. What is lacking is an additional sensor at each location that would link to the tire's TPMS and relay those positions to the ECU and ultimately the display.

Previous threads:

Discussion 1

Discussion 2

 

Thanks ..had time to read thru them .. when I have a bit more time I'll double check what 2 thru 5 are on mine ..at least I know top dog is the spare , and I'm glad it actively monitors that ..

 

It's a rather obnoxious "oversight." Even my Silverado indicates "Left front", "Right rear" etc. Of course, these have to be resynced with rotations, but at least you know where you stand and it only takes a minute with the re-learn tool.

I keep 40+psi in my spare. 1) That takes one more tire out of the "guess what tire we're talking about" display on the dash and 2) I rarely have to fuss with inflating it in the trunk to keep the tpms happy.

Amazing that my LS can park itself, but not accurately tell me which tire needs to be topped off.

 

actually a lot of other brands are able distinguish (bmw, acura, etc...)

i can't understand why lexus isn't doing that yet, that's one thing i thought they'd upgrade during the facelift

 

Well, I typically check mine once a month w/ a gauge, which I slipped a week or so on, and I probably wouldn't have checked the spare, because, with my previous car ( BMW M3), I didn't have one, so i probably would have forgotten about it .. Also,I find the system on my 460 miles ahead of the indirect system on the M3; That one gave the yellow light ..that was it ..and it was a pain in the rear to reset and keep reset, especially in a pothole-laden environment .. Now if I can figure out if it was Lexus or the previous owner that seemed to coat the spare wheel and tool kit with cosmoline or some other mildly greasy compound , I'll be set

 

I agree that this is the biggest and one of the only pet peeves of my with the LS. I wonder if they fixed that oversight for 2010? I keep a note on the vanity mirror with which tires are in what order on the display. There is one list for the 0 to 5000 miles rotation and another list for the 5000 to 10,000 rotation. I use TRIP ODOMETER A to remind me that I am on the 0 to 5000 (or 10 to 15K) and TRIP ODOMETER B in the display to remind me that I am on the 5000 to 10,000 rotation (and so on). But I am a little OCD!

 

I am not aware of any car with a direct measuring TPMS that can know the position of the tires whose pressure is being displayed without being told by a person. As far as I know the tire displays of all cars are subject to being scrambled during rotation or brake repair or flat/swap or other maintenance that involves removal of tires. Some cars, US cars, have a system that can learn tire positions through owner intervention. Most of the Japanese cars must be informed by a technician when tires are repositioned if you want the display to follow the change.

 

My Genesis sensed the tire position, regardless of rotation -- I believe each wheel position had a transponder of sorts and told the ECU which wheel sensor was closest to it. I'm not sure how it worked, but I do know you could rotate front to back and it would pick that up automatically.

In the case of my Silverado and my Navigator, there is a relearn procedure -- simply engage it, hold the tool in front of each wheel, the horn beeps and it resets the system. I really don't even see the point in marking independent wheel positions in the Lexus since you can't keep track of it. A simple "one of your tires is low, guess which" would have the same end effect.

All that said, it's one minor annoyance in an otherwise near-perfect vehicle... I can live with it!

 

not really, my m3 is an example already. it tells me exactly which tire is low on pressure. after tire rotation, all you need to do is just press on the tpms button and it will re-initialize itself. comes in very very handy rather than scrambling between 4 tires

 

Wow! This is a very complex issue. Here is a link to a good article regarding the complexities that have evolved due to the unregulated implementations of the NHTSA mandated TPMSs.

http://tirereview.com/Article/59528/...ve_tricky.aspx

As rominl has told you, and I am misinformed about, some of the European cars have a Direct TPMS with a display that maintains synchronization autonomously. The apparent disadvantage for these systems is that they cannot display the spare probably because they work by measuring the signal strength from antennas near the wheels and the physical separation for the spare would not be sufficient to allow reliable operation.

Since this discussion is about LS460s I will try to remember to limit my comments to 460s.

The LS460s use a Direct TPMS. The tire-sensor IDs must be loaded into the car's computer with an electronic tool. The order of display is a result of the order of entry of the sensor IDs.

The purpose of the TPMS reset switch in the LS460s is to allow the owner/operator to enter a benchmark pressure for each tire into the car's computer. The benchmark pressures are used to calculate the low pressure warning thresholds. The low pressure warning thresholds are calculated at 20% below the benchmarks and on a per tire basis. As an example, this would allow you to operate your front tires at 30PSI and your rear tires at 36PSI if you ever wanted to do something like that.

Injudicious operation of the reset switch will compromise the utility of the TPMS. It is never correct to reset the TPMS in response to a low pressure warning. Low pressure warnings are self clearing when the pressure is restored to normal and the ignition is cycled.

An example of the wrong way to reset the TPMS is doing a reset on a very cold morning to silence a low pressure warning. If the tires were at 25PSI due to permeation loss and very cold temperatures and you do a reset, then the low pressure warning threshold will be set to 20PSI and although that will silence the alarm, your tires will have to be dangerously low before you would get a warning.

Another example would be doing a reset when the tires are hot. If the tires were at 38PSI and you do a reset, then the low pressure warning thresholds would be set to 30PSI and the next time there is a seasonal decrease in temperature you would get a low pressure warning.

A tip for keeping your spare from being a TPMS problem: Inflate all your tires, including the spare, to the desired benchmark pressure - 33PSI is the recommended pressure - and do a TPMS reset. Then inflate your spare to 40PSI. This will allow you about a year before you have to add air to the spare to compensate for permeation loss.

 

I actually like the way that Japanese cars don't care about TPMS orders.

It is much easier that you don't need to reset the "tire order" when tires get rotated. It is a pain to reset some of the American models in ordor to see tires in correct position, and some American models require special tools, air pump, and about 20 minutes of time (for a pro) only to reset the system.

These American models does get charged between $40 to $80 for tire rotation service, and I know there are people hate to pay this much because the way it was designed.

FYI,

 

hahahaa, that's why you don't care about domestic cars the system in my bmw can't be easier. press of a button, 10 seconds, done

jmcraney, great info there, good read! if possible i do want to know what lexus have to sy as well. the fact that they are able to get the reading of the tpms on the exact pressure, to me that means they should be able to get the location as well with some careful design. it's not like the size of this car is a yaris where there can be confusion on "distance", it shouldn't be hard to get the location as well.

i have always heard people complaining saying that they see one tire is low but no idea which one. maybe something lexus can improve on

 

Agreed.

One way of relating the tire pressure with the tire is by adding more air to the tire(A Job of Two).


-This is an example, Your tire pressure readings are as follows:
260
250
250
260
250

- Sit inside the car and watch carefully the tire pressure change while more air is added to the tire.It takes around 5-10 seconds for the reading to change in the display.(Could be done by yourself but you have to let the driver window down and set the display to the tire pressure,)

- For Example lets say the FR is being filled with air. Keep watching the Tire pressure screen till you note a jump in pressure, For instance lets say
*
*
280
*
*
-Using your Phone Note Down Tire Position:
*
*
FR
*
*
-Once you know All tire Pressure, Save that Message in your Drafts.

I did this twice:
Previously with OEM Factory wheels to know whats my configuration and it helped when i ran over a nail, I figured out the tire by going back to my phone and checking the order .

2nd time was when i had the WALD rims installed the order was changed and i had to redo.