Tyre Pressure Monitoring System

**alphabeatsco** · 10-11-2013, 11:16 PM

The warning light came on.
I've checked the tires and pumped it to 38psi.
these are the 18inch wheels with factory tyres.

after 1 week, the light came back on.

can the light warn about tyre tread?

**GTD_XU1** · 10-11-2013, 11:23 PM

My Golf has a button in the glove box to reset the warning system after inflating tyres, check your handbook for details on how to set your's.

**alphabeatsco** · 10-11-2013, 11:24 PM

sorry, i should have stated.
i have reset it, and after one week, it came back on

**GTD_XU1** · 10-11-2013, 11:42 PM

Sounding obvious again, but unless you have a tyre leak it sounds like a trip to your favourite trusted mechanic or dealer. Some one more knowledgeable will probably chime in tomorrow. Good luck.

**GTi Crow** · 11-11-2013, 06:52 AM

Had a similar issue but it would come on after about a month. Regular checking of the tyres (with my own gauge first thing in the morning before I had driven the GTI) showed I had a slow leak in one tyre. Made sure I reset the tyre warning every time I put air in the tyre to 38psi. Tyre light would come on when it dropped about 4psi - may have been a faulty valve. Tyres were needing replacement in the near future so I put up with it until replaced tyres - since then no issue.

**sVWatt** · 27-02-2014, 05:50 PM

Tyre Pressure Monitoring System-tpms_warning_light-jpg

I had the tyres rotated at the last service, and decided to check their pressures last week. All was good at 28.

Then Tuesday morning, my low tyre pressure light came on. The car didn't pull to the side, so I figured it must be a slow leak. Yesterday I pulled into the same garage to use the air pump and gauge and was surprised to find all four tyres were 24.

Pumped back up to 28, and the sensor reset.

Could it simply be the cold spell Canberra is now in?

**Diesel_vert** · 27-02-2014, 07:22 PM

For a fixed volume (i.e. the inside of a tyre, which is close enough), the pressure of any gas will change by approximately 10 kPa (1.5 psi) for every 10°C change in temperature.

This explains why the tyre inflation pressure increases while the vehicle is driven, as the friction generated by the tyre heats up the gas inside it. For instance, a tyre with an inflation pressure of 250 kPa (36 psi) at 20°C will have an inflation pressure of 270 kPa (39 psi) at 40°C.

It also explains why the inflation pressure decreases when the vehicle is left outside overnight while the ambient temperature drops. For instance, a tyre with an inflation pressure of 250 kPa (36 psi) at 20°C will have an inflation pressure of 230 kPa (33 psi) at 0°C.

Therefore, it is important that the tyre inflation pressure is adjusted when the tyres are cold - i.e. at ambient temperature, preferably in the morning, before they are warmed up by the sun's rays.

Adjusting the inflation pressure while the tyre is warm will lead to the tyre being underinflated.

Originally Posted by sVWatt

I had the tyres rotated at the last service, and decided to check their pressures last week. All was good at 28.

Then Tuesday morning, my low tyre pressure light came on. The car didn't pull to the side, so I figured it must be a slow leak. Yesterday I pulled into the same garage to use the air pump and gauge and was surprised to find all four tyres were 24.

Pumped back up to 28, and the sensor reset.

Assuming you are referring to the car in your signature, did mean to type 280 kPa or 2.8 bar (both of which are fine) or 28 psi (which isn't fine)?

What are the inflation pressures (for normal load) stated on sticker inside the fuel flap?

**brad** · 28-02-2014, 07:15 AM

Tyre pressures vary with the temp of the tyre. Maybe that was it.

More to the point WFT are you doing with the tyres at 28psi?

32psi should be a minimum no matter what the manufacturers plate inside the fuel cap says. They are trying to find a compromise between ride & handling & don't really care about tyre wear & life. Also, they do their testing in Europe where the ambients are generally lower than here.

If nothing else, run them a bit higher to avoid the situation that you were in - eg: thought they were right but for some reason they were all low.

**mozzatron** · 08-03-2015, 11:15 PM

I've double checked and each tyre is at 40PSI

When i go to reset it with the button in the glove box it won't reset.

Any ideas what the issue might be?

**minke** · 09-03-2015, 09:30 AM

Starting with the simplest thing. You've got to hold down the reset button for a few seconds. I'd hold it down for at least 10 seconds and see what result you get. Then try 30.

Try with Engine running, then with engine off with car on reds (the notch before starting)

Also ensure the car is in park (if auto).