ghmundt

I purchased a second set of rims and tire pressure sensors from the Tire Rack for snow tires on my 460. Since installation, the tire pressure display on the dash only displays the pressure reading by wheel if I stand still long enough before driving. If I do not wait long enough before driving, the pressure will not be displayed and will ultimately display the tire warning symbol. My first thought is the Tire Rack sold me the wrong sensors, but they insist the Pacific 315 MHZ sensor they sold me is the same as Lexus uses.
Can anyone help me with this problem?

jmcraney

What is likely happening in your situation is that the new sensors are not registered in your car's computer and the old sensors are still registered. What happens in a case like this is that when you start your car the old tires - the ones with the registered sensors - are close enough to your car to be received by the TPMS (the TPMS will only display pressures for sensors that are registered) and then when you move out of range the signal is lost. Or, if you have stored the old sensors in your car's trunk that causes a problem. You also need to keep in mind that the sample rate is about a minute or two so your display will initially read "checking" until it gets a signal from a sensor that is registered.

So, what you need to do is go to a dealer or tire shop that has the electronic tools to read the sensor codes from the new sensors and register then in the car's computer. Five codes, four on the ground and one spare, need to be registered. The Lexus LS460 requires a physical connection from an electronic tool to the car's data bus to enter the codes. The sensor codes can be read wirelessly from the wheels with a electronic tool. Many tire shops have these tools but the TPMS systems are so varied not every knows how to do this.

ghmundt

Thanks for the great response. Is there an A B switch on the 460 so I can have 2 sets of wheels registered and easily switch between winter and summer wheels? Or do I have to reregister the wheels each time I change them?

jmcraney

Unlike some of the other Lexus cars, the LS460s store only 5 sensor codes. And don't forget to benchmark the sensors when you change as that is something that the dealer/tire-shop may forget to do or do incorrectly and the result of that could be an irritation or safety issue.

edarte

I wanted a second set of rims for winter tires and had read that the LS requires that each time the rims are swapped I would have to return to the dealer to get them re-registered. As the closest Lexus is over two hours away I decided to do without the sensors and put up with whatever warnings come up.

Well I just swapped the rims for the first time this week and all the TPMS is showing is "checking". No lights, no bells or buzzers, nothing. If I did not go to the tire display I would not even know it was checking.

Is this correct? I had assumed that, given my wheels are all "theoretically" under pressure, the system should be raising some alarm.

I was concerned that I would have to put up with annoying alarms until I swapped the original rims back so I prefer this behaviour. But I am wondering if maybe my TPMS is not working right and I need to raise with the dealer? Not a lot of value in a warning system you need to check each time to see if there is a problem.

jmcraney

Sounds like everything is normal. The only thing that causes an alarm is a sensor reporting a pressure that is below the alarm threshold for that sensor. "Checking" is a non reporting sensor which in not a pressure below the alarm threshold.

edarte

Well, it would be good if you are right. It means that I don't have to put up with nuisance alarms if I want winter rims but don't want to spring for extra TPMS sensors. I had read at least one earlier post where someone said that the tire info display came up and you could not change to another screen due to the warning but I now assume that was on either another model or another year.

Again thanks for the feedback and I will hold off on raising it with my dealer.

edarte

Just to update this post on my TPMS behaviour.

When I first drove away from the tire dealer (with summer rims+sensors in car) all the display showed was “Checking” for each tire. No alarms on drive home. No alarms next day at start up. This was no doubt due to the fact that my summer tires/rims (+ sensors) were within range in my garage. In fact I did not get an alarm for the next four days??? (Why it took five days to trigger alarm is strange. If tire was actually low then five days of driving could do a lot of damage)

Then on day five, after driving about 10-15 miles, the alarm went off saying there was an inflation problem. I could still see the other displays (e.g. gas MPG since refill, etc.) but could no longer see the compass reading. Tire pressure warning light flashed yellow on dash for a few minutes then just stayed on. Overall nothing too annoying compared to the nuisance and cost of second set of sensors.

When I returned to my garage if I leave car on for few minutes then warnings do not appear when I leave next morning but do return after 10-15 miles.

Shibumi1

anyone have this issue? was driving last night. screen popped up with tpms failure take car to dealer.. so i pulled over checked all 4 wheels..all was good, so i shut off an restarted the car.. no change.. i drove off 5 mins later it started workin again... any ideas? fyi i have my factory wheels with factory sensors

CJITTY

Sorry, but this is simply not true. I purchased two sets of 4 new OEM tpms sensors for $184 shipped via eBay via seller "wheel1x" earlier this year. Part # PMV-107J and I posted this in the LS460 wheel and tire information sticky thread. http://item.mobileweb.ebay.com/viewitem?itemId=280740027914

I searched just now and they have some used ones at the moment, but I would email the seller. The same part number is used on many toyota, lexus and scion models. There are other companies like "Orange TPMS' that can provide new sensors pre-flashed with your existing sensor IDs already programmed. If folks want to get ripped off at dealer, be my guest. but folks have much cheaper options to get OEM or aftermarket sensors. And Discount Tire usually reprograms to your car for free when you buy tires or get these installed. I had to order two sets for aftermarket wheels and this deal was amazing. Sensors are still running fine, but then again all 8 were brand new!

jmcraney

I won't argue price and I will delete my comment. Thanks for keeping me straight.

Shibumi1

well i'm curious if its a battery problem as the system went down an wouldnt show any of the tires... the screen wasnt even avail to see which wheel wasnt reading.. it said "tire pressure system failure" i've had a flat before and it still showed the other wheels. then five mins later it all worked again.. i find it hard to believe that all 5 sensors went dead all at once.

CJITTY

All good man!! That's why we have this awesome forum to help everyone out Without all of your help on the wind noise issue, we would all be screwed..you single handedly saved LS owners from countless frustration with that issue!!!

jmcraney

I think it is the case of a "non-reporting sensor" (because the sensor battery has failed) and seems like the way it works is that if any of the five sensors fail to report for 30 minutes then it is considered a system failure. Normally the sensors report the tire pressures every 30 seconds or minute or so but for lots of different reasons the car can miss some of those reports without sensing a problem. You can test this for yourself by taking your spare out and leaving it in the garage. If the car gets a pressure report from the spare before you drive away then if you continue to drive you will have 5 pressures displayed until the 30 minute mark and then system alarm. Then if you stop, out of range of the spare, and turn your ignition off and then restart the car you will have four pressures displayed and the fifth display will show something like "checking" until the 30 minute mark and then it will display system alarm.

If you started in your garage with one sensor not reporting then you would have 4 pressures displayed and the fifth sensor would show "checking" until you have driven 30 minutes and then system alarm.

Since I am old and my memory is not as good as it once was then the 30 minutes may not be the right number. Here is your chance to try this out and tell us if it works that way or even better how it works.

A flat tire is not a non-reporting sensor - it is a sensor reporting a low pressure.

Shibumi1

sounds like a plan.. let u know tomorrow