tyre pressure warning

[captainslow]

does anyone know how will the tyre pressure warning come on ?? I checked the tyre pressures last night and a bit annoyed the tyres are 4psi lower than the set pressure last time when it was checked and no warning on the dash all these time...

 

[Lima]

Were they all around 4psi lower?

AFAIK the sensor works off the ABS and basically measures rolling diameter, so if one tyres is lower, and therefore has a different rolling diamater the warning light will come on. If all four tyres decrease in pressure at roughly the same rate, then the warning light won't/can't be triggered.

 

[DRMAT]

Did you reset the pressure indicator when you last did your tyres? If it was set for 32psi (or rather the rolling diameter 32psi gives) and you put your tyres up to 36psi then it isn't going to come on til you've lost that 4psi. Haven't tested it to see how sensitive it is though but i've never lost any pressure between checks anyway.

 

[captainslow]

Were they all around 4psi lower?

AFAIK the sensor works off the ABS and basically measures rolling diameter, so if one tyres is lower, and therefore has a different rolling diamater the warning light will come on. If all four tyres decrease in pressure at roughly the same rate, then the warning light won't/can't be triggered.

yeah they are all evenly 4psi out, i guess that explains it...

 

[captainslow]

Did you reset the pressure indicator when you last did your tyres? If it was set for 32psi (or rather the rolling diameter 32psi gives) and you put your tyres up to 36psi then it isn't going to come on til you've lost that 4psi. Haven't tested it to see how sensitive it is though but i've never lost any pressure between checks anyway.

yeah i reset that everytime i fill it back up.

but how many psi is it supposed to drop before the warning comes on ??:iono:

 

[Discotheque]

yeah i reset that everytime i fill it back up.

but how many psi is it supposed to drop before the warning comes on ??:iono:

As was stated earlier it won't come on if the pressures are reducing at roughly the same rate. It is only if one tyre loses more pressure than the others than it is triggered.

So you still have to regularly put air in your tyres but if (like me, twice) you end up with a screw in your tyre and a slow leak the warning will come on and you will know one tyre has an issue. I don't know exactly how much the pressure has to drop to come on but mine was around 6 PSI down I think (that is a vague memory) when it came on.

 

[Uthor]

Reading over the technical bulliten posted on VWVortex (http://forums.vwvortex.com/zerothread?id=2989583), it seems like the system should work on pressure alone.

Even without tire rotation, a pressure increase or decrease will cause the sensor will send a signal.

The only thing tire rotation does is signal the sensor to send information to the car (eg, you're driving down the road at constant speed, the sensor will see you are moving and will send its signals).

There is nothing on the page that indicates that the car is checking tire pressure using the ABS system and rolling resistance. What would be the point of internal pressure sensors inside the wheel at that point?

 

[mistaka0s]

Keep in mind that sensors within the tire appear to be North American models only.

Rest of the world AFAIK (at least in Australia), uses the ABS sensors to calculate rolling diameters.

Reading over the technical bulliten posted on VWVortex (http://forums.vwvortex.com/zerothread?id=2989583), it seems like the system should work on pressure alone.


The only thing tire rotation does is signal the sensor to send information to the car (eg, you're driving down the road at constant speed, the sensor will see you are moving and will send its signals).

There is nothing on the page that indicates that the car is checking tire pressure using the ABS system and rolling resistance. What would be the point of internal pressure sensors inside the wheel at that point?

 

[mljchan]

yeah they are all evenly 4psi out, i guess that explains it...

hey captainslow, did you use the same guage to measure your tyre pressures?
if you did, is it possible that the guage is now faulty?

 

[funny]

Keep in mind that sensors within the tire appear to be North American models only.

Rest of the world AFAIK (at least in Australia), uses the ABS sensors to calculate rolling diameters.

Errr, not quite. My neighbour has the wheels with those small metallic stubby bits where you pump up the air (ok i forget what they are called, but i just got up...).

IIRC 05-06 models got the in-tyre system. 07 onwards use the ABS. My neighbour's car is a late calendar year 2006 model (by would be MY07), whereas mine is a Jan 07 build date.

 

[funny]

Just looked at the TPMS TSB.
Guess they changed over to ABS system to monitor as the older TPMS system also measured temp differences. Guess enough people lived in an area with a big enough diurnal range to set off the TPMS light. ABS doesn't measure temp so it's not affected.
Would be great to see what tyre temps are like mid-drive though. So F1!

 

[Uthor]

Keep in mind that sensors within the tire appear to be North American models only.

Rest of the world AFAIK (at least in Australia), uses the ABS sensors to calculate rolling diameters.

Sorry, I was just pointed to this thread from another one as explanation of the tire pressure system and it didn't sound right. I didn't know Australia was different.

 

[SideFX]

My GTI is MY06 and it doesn't have the TPMS nor I do Tiny's MY05.

 

[Discotheque]

My GTI is MY06 and it doesn't have the TPMS nor I do Tiny's MY05.

Well that is strange, I thought it was Standard on all Aus cars??:iono:

 

[dodgey]

Well that is strange, I thought it was Standard on all Aus cars??:iono:

FAIK, unless it is an aftermarket kit, or a special order, I had always thought that we in Aus only got the ABS TPMS for the Golf and not the in wheel type. :iono: