jkonquer

I got a nail on my rear passenger tire (after owning the vehicle for less than 2k miles FTL), replaced it with the spare tire and would be taking it to a tire shop to get it patched.

I'm assuming the spare tire on GX's are full size tire. So does that mean the spare tire have a TPMS and would I need to re-program it if the spare tire is used as a replacement? The low tire pressure indicator is still on even with the spare tire on and the punctured tire/wheel off of the vehicle. Would everything reset itself once the original tire/wheel is back on?

thanks

EXP_Cougar

In their ultimate wisdom, Lexus did not make the TPMS indicator specific to the tire. So if any of the 5 tires (yes the full size spare has a TPMS) goes low, the indicator will light up. Since you have a flat, that sensor will stay lit until you get it taken care of and aired back up.

jkonquer

Ok thanks for the quick response.

Also I noticed that the spare tire pressure was set at 42 psi when the suggested pressure is at 32 psi. Is this normal? And what's the threshold for the sensor to go off?

EXP_Cougar

Not sure if it's normal - have not checked the pressure in my spare yet.

​​​​​​I want to say that it's a 5psi threshold for the tpms warning to trigger

Carnevino

jkonquer

btw, what can you do with the chain when there is no spare ? is there place to hang the chain from moving around?

EXP_Cougar

Not something I ever thought about though you can probably use something like a zip tie to gather it and secure it. Or place the punctured tire in its place.

Acrad

IIRC low PSI threshold is around 26PSI. This shows in Techstream.... I think I called it up as a gauge in Fusion and it showed 26 PSI there as well.

The spare does have TPMS and no way to program it out

It is possible to read TPMS values with this OBD adapter and OBD Fusion. It has to be a genuine 2.0+ chipset ELM adapter... the cheap ones don't work.

https://www.clublexus.com/forums/gx-...l#post10279193

You can quickly identity what tire is 1-5.... just let air out while you are reading values.

jkonquer

I got the tire back and they plugged it instead of patching it.

I'm sure it should be ok, but I'm debating whether I should keep the new full size spare and use the plugged tire as a spare.

btw the low pressure warning lights are gone and set all tires at 35 psi. Hope this will improve the mpg.

Craigyyy

Yeah TPMS will light up if any tire gets low. Took me about 20m to figure that out one day after getting all my pressures perfect and the light was still on.

Personally I would ride on the plugged tire, and replace it when it's worn out. Your spare will likely sit under the car for a very long time, plug will likely dry out, and you'll have to address it in the future.

You could take the tire to another shop and have them patch it if it makes you feel better. But the plug should last the life of the tire.