Recommended Posts

Well this morning it was below zero under my carport and when my car was started the tyre pressure warning light was on. Well I looked everywhere including the handbook and nowhere did it say how to reset the thing. Fortunately after driving for half an hour the light disappeared. Why isn't there information on resetting the light when the cold wat

Weather  certainly the issue? 

Share this post


Link to post
Share on other sites
 

20 minutes ago, olliesgrandad said:

Well this morning it was below zero under my carport and when my car was started the tyre pressure warning light was on. Well I looked everywhere including the handbook and nowhere did it say how to reset the thing. Fortunately after driving for half an hour the light disappeared. Why isn't there information on resetting the light when the cold wat

Weather  certainly the issue? 

The tyre pressures should be set in the monitoring system while the tyres are cold and at the correct pressures "cold". So it is likely that a tyre is low on pressure even though it is higher than the warning trigger limit when warm. Warm pressures should be higher than the pressures shown on the door jam lable.

John.

Share this post


Link to post
Share on other sites

Your tyres are probably a bit low, combined with the cold weather than has dropped the pressure by 2 or 3 deg compared to a 'cold' 20 deg in the summer. Set your pressures to the correct cold temp and recalibrate the system.

Share this post


Link to post
Share on other sites

14 hours ago, olliesgrandad said:

Well I looked everywhere including the handbook and nowhere did it say how to reset the thing.

This is for my RC but I believe the button location is similar for most models? It is very awkward to access ...

image.png.aa1d4733a79ec647f3092fb52c6f5e35.png

How to initialise the tire pressure warning system

  • Park the vehicle in a safe place and turn the power switch off.
  • Initialisation cannot be performed while the vehicle is moving.
  • Adjust the tire inflation pressure to the specified cold tire inflation pressure level. 
  • Make sure to adjust the tire pressure to the specified cold tire inflation pressure level. The tire pressure warning system will operate based on this pressure level.
  • Turn the power switch to ON mode.
  • Press and hold the tire pressure warning reset switch until the tire pressure warning light blinks slowly 3 times.
  • Wait for a few minutes with the power switch in ON mode and then turn the power switch off.
  • Like 1

Share this post


Link to post
Share on other sites

As the very useful post above, but note in two places it stipulates the pressures, and setting of the system should be done "cold".

John.

Share this post


Link to post
Share on other sites

My tpms warns of check system when cold, Battery on one is on last legs, so when cold, fails. When warm, returns back to life. Cycled about 20 times lol.

Not even been out to the Lexus with the snow, its 14 inch deep here, so took the dirt bike to work yesterday, was fun bar the white outs, one of which saw me nearly hit someone house having rode right up their garden. but was pure ice on way home, so stayed indoors today.

Drive safe folks

Share this post


Link to post
Share on other sites

Well a bit warmer today so checked and pumped the tyres to recommended pressure. Warning light still on. Drove car a couple of hundred yards and it reset. 

Share this post


Link to post
Share on other sites
On 3/3/2018 at 11:14 PM, olliesgrandad said:

Well a bit warmer today so checked and pumped the tyres to recommended pressure. Warning light still on. Drove car a couple of hundred yards and it reset. 

The pressure monitors in the tyres do not continuously transmit the information just every few minutes. This is to save Battery life in the monitors. If they transmitted continuously the batteries would not last long, and this is the reason for the delay.

John.

Share this post


Link to post
Share on other sites

How cold is cold? 

Share this post


Link to post
Share on other sites
1 hour ago, Ala Larj said:

How cold is cold? 

Cold pressures are considered to be the temperatures of the tyres after standing for 2 hours minimum without being driven.

John.

Share this post


Link to post
Share on other sites

But that could be a huge difference in temperature between summer and winter!

Share this post


Link to post
Share on other sites
37 minutes ago, Ala Larj said:

But that could be a huge difference in temperature between summer and winter!

I agree, but the difference is not as large as the variation when checking tyres hot as both the speed driven, the duration, load carried, ambient temperature, and possible under or over inflation in one or more tyres would affect the readings

Share this post


Link to post
Share on other sites

The important measurement is pressure, not temperature but as the pressure changes with temperature the only way to correctly measure the pressure of air in the tyre that air must be at the same temperature as the atmosphere surrounding it.

So, it doesn't matter what the ambient temperature is, just so long as the air in the tyre is at the same temperature.

Manufacturers factor in the the heat generated (above ambient) in the tyre by the amount of sidewall movement allowed by the inflation pressure. 

 

Share this post


Link to post
Share on other sites
11 minutes ago, NemesisUK said:

The important measurement is pressure, not temperature but as the pressure changes with temperature the only way to correctly measure the pressure of air in the tyre that air must be at the same temperature as the atmosphere surrounding it.

So, it doesn't matter what the ambient temperature is, just so long as the air in the tyre is at the same temperature.

Manufacturers factor in the the heat generated (above ambient) in the tyre by the amount of sidewall movement allowed by the inflation pressure. 

 

That makes sense, thanks.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now