I have a 2007 Lexus RX 400h produced for USA market but I use it in Europe.

When I bought it from the previous owner the TPMS light was blinking which he explained was from expired batteries on the sensors. Last week I finally got round to replacing the sensors on all 4 wheels. I bought original Pacific sensors and brought the car to my local Toyota dealer to have them installed and registered. When they finished the work the light was off but started blinking again after 30 min of driving and remained so for the next week when I returned to the dealership.

I've done some reading beforehand and was almost sure it was from a bad sensor that I bought. They checked the sensors and said they were good. Re-registered them again and handed me my car back. After some 30 min of driving the same thing happened. I'm a bit angry at the dealership because they went the route of least resistance -re-registered the sensors without even checking the DTC codes through OBDII. I saw them using some wireless tool in the likes of MAXITPMS and not the Toyota Techstream. I've been reading some more because as I see it if i don't solve the issue the dealership won't do it for sure.

First I've read in this article (https://www.autoserviceprofessional.com/articles/7814-dealing-with-tpms-problems-tips-to-avoid-issues-and-diagnose-glitches) that all sensor positions have to be filled in the ECU. As the second generation of RX's had 5 positions (4 wheels and one spare tire) me only registering only 4 sensors could be the cause of the error. I had to replace my spare tire after I had bought the car and haven't installed a tpms sensor on it. As the dealership was using a wireless tpms tool for registering the new sensors and not tech stream could them ommiting to program the 5th position force the ECU to generate the error. Or can a former id be storred under the 5th position (from a previous registration) which now generates the error code ?

 

Hi, I'm a little confused, the Standard in the US, is if the vehicle has a Full Size Spare Tire and the Vehicle has TPMS sensors, then the spare must have a TPMS Sensor on the spare tire as well.
The '07 RX400H comes standard with a Full Size Spare on a Alloy wheel. You should have a TPMS sensor in the wheel, I didn't know if you checked that. If Not, that could be your issue. I'm very surprised the dealer didn't check that, and YES if the sensor in the spare is BAD, it will cause the TPMS light to come on.
FYI- My 2005 RX330 US model doesn't have TPMS Sensors per se, but it has a TPMS light.
it uses the ABS Tire Speed Sensors also for the TPMS function.
As the tire gets low on air, the tire diameter gets smaller and the tire speed changes, and trips the TPMS light.
Also, because this type of system is used, there is nothing on the spare tire and it doesn't affect the TPMS. The ABS Tire Speed Sensor reads from a Sensor Ring on the brake rotor, that's oversimplified, but you get the Idea.
This type of TPMS was used early and mainly on European cars and some Japanese models, it's not real common. I hope this Helps.

 

Well I had the full sized wheel and all but used the alloy wheel as a substitute for a destroyed one and discarded the dead (as I thought then) TPMS sensor installed on it. When I installed 4 new sensors on all driving wheels and got them registered in the ECU that left me with a spare without a TPMS sensor when I reinitilazed my TPMS system on my Lexus.
I've read on Toyota Tundra forums that no TPMS sensore on Spare wheel will cause the TPMS light to blink after 15 minutes of driving even if you enter 0000000 in sensor id in Techstream (which shoud turn that position off).
As far the fact that the dealership doesn't know such facts It is no surprise to me. Most car mechanics in such places are students in my country with one or two senior mechanics on a shift. They give simpler jobs to those guys and that is why the low quality of service.

 

FYI - When the TPMS sensor on the spare tire went bad on my 2012 RX350 US Model, the light never went out, until I had the sensor replaced and programmed. Maybe they made a change since Your car was made, Good Luck with Your Issue.

 

I am guessing that the tpms computer waits some amount of time to communicate with the sensors. Since there is not a sensor in the spare tire, the tpms computer times out and then turns on the tpms light in the dash.

 

I don’t know if I’m grasping at straws here but this is the version I think is mostly probable. I’m going to make an appointment at the dealership tomorrow but because its an hour’s drive form me, it won’t be till next week when I visit them.
It’ll be an embarrassing visit for sure because now I would prefer If they would just hand me the techstream an let me diagnose it myself.

 

Just was wondering if their is a just a simple way to disable the TPMS so that you do not have to deal with the warning light being on?

 

I'm afraid that apart from disabling the light on the dashboard there is no other way to fix it. The annoying thing is that together with the orange tpms light there is a giant red triangle at the center of the dash with a big a%% sign "CHECK SYSTEM" that can't be canceled because TPMS is treated as a crucial system.

 

This^^^^^^^^^^^

 

Couple of things. You have a US market Lexus in another country. Not sure of the requirements in Europe but unless it’s common place to have US versions there can’t really expect them to know every US detail. Knowing your vehicle had a spare tire with a sensor in it you only bought 4 sensors and gave them that to work with. The Bartec scan tool that I have a lot of experience with will tell you that you are missing the 5th wheel when reprogramming but I don’t think that’s the case with all scan tools. However I can tell you that even though I can’t explain why it happens, some Lexus/ Toyotas have the same issue your having when they are required to only have 4 sensors. Every Toyota/Lexus that I reprogram we scan all sensors and then program them into the ECU. Immediately after without turning the ignition off you need to scan each sensor with the tool again as if your starting over. After each sensor has been rescanned you can now turn the vehicle off.
https://www.dillvalves.com/wp-conten...s/RL-A1229.pdf

 

I concur^^^^^^^ The OP's post title says it all......Toyota supplied a matching wheel/tire assembly as a spare, so it makes sense to have the spare equipped w/ tpms sensor....