XC70: Wheels/Brakes Tyre pressure faulty warning

[Goldfish888]

My 3 months old XC70 started displaying low pressure icon on dash . I checked tyres pressures and they are correct each time I recalibrated and icon disappeared from dash . but icon will appears again after a couple of hundred miles. and again tyres pressures are ok . The problem is now recurring regularly. Can anyone got this problem or can cast light to this problem . thanks in advance

[Clan]

Originally Posted by Goldfish888

My 3 months old XC70 started displaying low pressure icon on dash . I checked tyres pressures and they are correct each time I recalibrated and icon disappeared from dash . but icon will appears again after a couple of hundred miles. and again tyres pressures are ok . The problem is now recurring regularly. Can anyone got this problem or can cast light to this problem . thanks in advance

what are you using to measure the actual tyre pressures ? one of those tubular ones with a scale up the side isnt really accurate enough. However what ever the tyre pressures are, After you calibrate the warning should not come up unless one or more tyre pressures alter significantly.

[Goldfish888]

Originally Posted by Clan

what are you using to measure the actual tyre pressures ? one of those tubular ones with a scale up the side isnt really accurate enough. However what ever the tyre pressures are, After you calibrate the warning should not come up unless one or more tyre pressures alter significantly.

I use a heavy duty 12v pump to check the tyres and so far none of the tyres showed a reduction in pressures when I had the icon showed up in the dash , After checking I then recalibrate and the wheel pictures on the calibration screen will turn green again , I drove for a couple of hundred miles or so and the icon will comes up on dash again . So far when I check the tyre pressures they are normal (within a couple of IBS)

[Clan]

Originally Posted by Goldfish888

I use a heavy duty 12v pump to check the tyres and so far none of the tyres showed a reduction in pressures when I had the icon showed up in the dash , After checking I then recalibrate and the wheel pictures on the calibration screen will turn green again , I drove for a couple of hundred miles or so and the icon will comes up on dash again . So far when I check the tyre pressures they are normal (within a couple of IBS)

I would have a word with the volvo dealer, they may have a service bulletin or software update for it. If not they can send a technical report to the technical centre at Daventry who are closely connected to Sweden.

[Tatsfield]

IIRC the tyre pressure system doesn't actually measure the pressure. It is an extension of the ABS system which monitors the rev rate of the wheels and if a tyre has a lower pressure than the calibrated standard pressure it will be softer and the circumference of the tyre will be different and this will be picked up by the ABS system and reported as a low pressure tyre. The fault might be a minor range fault for an ABS sensor. If you have a VIDA/DiCE diagnostic, that might identify a faulty ABS sensor which could then be changed out.

[Goldfish888]

Originally Posted by Tatsfield

IIRC the tyre pressure system doesn't actually measure the pressure. It is an extension of the ABS system which monitors the rev rate of the wheels and if a tyre has a lower pressure than the calibrated standard pressure it will be softer and the circumference of the tyre will be different and this will be picked up by the ABS system and reported as a low pressure tyre. The fault might be a minor range fault for an ABS sensor. If you have a VIDA/DiCE diagnostic, that might identify a faulty ABS sensor which could then be changed out.

Thanks for the response . Thus far in each occasion when low pressures warning came up,checked the tyre pressures,they were normal. what is '"minor range fault"
Car booked into independent Volvo specialist next week will see if they can fix it

[Tatsfield]

By that I mean that the readings from a faulty ABS censor would be enough to trigger a tyre warning but not enough to erroneously trigger ABS braking. This is all guesswork!

[Goldfish888]

An update car been to garage no fault found except one tyre was out of balance. .That was rebalances. Dash warning still comes up but I now spotted a warning pattern it appears to come up after car driven in a traffic jam for a while. Could that be the cause??? I really don't know