Tire pressure and Windshield washer fluid

[CorollaS671]

Arent these suppose to illuminate in the cluster when low? If so how low should it be....cuz even when at 29psi on the tires stil no sign and as for the washer fluid signs of low pressure of the fluid showed no sign of low washer fluid....

 

[brothabear]

Every time my tire pressure light comes on it's around 23 PSI, but this is on aftermarket wheels. Not sure if it would be any different on stock wheels.

 

[jolly]

TPMS light up at the programmed air pressure. If it's not correct, you could inflate your tire to desired specs then reset the system (procedure in owner manual).
Washer fluid on my Corolla goes on when there's almost nothing left in the reservoir.

 

[CorollaS671]

Thanks guys

 

[klinetime574]

Just to chime in here, got similar results as @brothabear Toyota guy told me the TPMS light comes on when tires drop below 75% capacity. My door jamb says 32psi. The light comes on when they hit 23psi (24psi being the 75% mark)

I wish it came on when they were 4-5 pounds low. Can make a huge difference in gas mileage with my commute.

 

[HanSolo]

Just to chime in here, got similar results as @brothabear Toyota guy told me the TPMS light comes on when tires drop below 75% capacity. My door jamb says 32psi. The light comes on when they hit 23psi (24psi being the 75% mark)

I wish it came on when they were 4-5 pounds low. Can make a huge difference in gas mileage with my commute.

Not to mention that air pressure that low can be outright dangerous if you are driving across the desert in extreme heat or during a snow storm(traction issue). Tires that are underinflated will get much hotter due to the additional heat from the friction and drag. I think Ford programs their cars to light up at 26psi or when one tyre is 8psi lower than the other. Still too low in my opinion.

 

[Michael Korologos]

Is there a screen that says the actual tire pressure or does the light just come on when it's low?

 

[jolly]

Is there a screen that says the actual tire pressure or does the light just come on when it's low?

No actual pressure. Just a warning light.

 

[Donabed Kopoian]

One thing you can do (if you want), is inflate your tires to 36 or 37 psi, set the pressure with the TPMS switch in the glovebox, then bleed down to 32.

That will get it to come on sooner. If it comes on too soon, then try 34 or 35 psi, and if it still comes on lower than you want, up it to 38 or 39.

 

[Donabed Kopoian]

As far as the low washer fluid indicator, I believe that is only for Canadian bound vehicles. U.S. vehicles don't have that sensor.

 

[klinetime574]

One thing you can do (if you want), is inflate your tires to 36 or 37 psi, set the pressure with the TPMS switch in the glovebox, then bleed down to 32.

That will get it to come on sooner. If it comes on too soon, then try 34 or 35 psi, and if it still comes on lower than you want, up it to 38 or 39.

That's a good idea, didn't think about that one. Would the computer recognize that math? Not sure how smart this thing is.

 

[jolly]

One thing you can do (if you want), is inflate your tires to 36 or 37 psi, set the pressure with the TPMS switch in the glovebox, then bleed down to 32.

That will get it to come on sooner. If it comes on too soon, then try 34 or 35 psi, and if it still comes on lower than you want, up it to 38 or 39.

That's a good idea, assuming that the "75%" below capacity is accurate. The only documentation from Toyota says it comes on when "air pressure is critically low". Unlike a screen indicating actual pressure in each tire, a TPMS light isn't that precise and its main purpose is to catch your attention. Think gas needle vs low gas light. It's still a good idea to check pressure manually from time to time.

 

[Donabed Kopoian]

That's a good idea, assuming that the "75%" below capacity is accurate. The only documentation from Toyota says it comes on when "air pressure is critically low". Unlike a screen indicating actual pressure in each tire, a TPMS light isn't that precise and its main purpose is to catch your attention. Think gas needle vs low gas light. It's still a good idea to check pressure manually from time to time.

You're right, but it will be a set percentage below nominal air pressure. The algorithm won't change; it just depends on the resolution of the TPMS sensors (which use a strain gauge so should be able to detect in increments of 1 psi).