Tyre Monitor
 

During a long drive home yesterday afternoon, my recently-acquired 2015 V60 D4 put up a persistent tyre warning message ... It mentioned one tyre being low, but the displayed graphic showed ALL four wheels as amber.

I accessed the tyre monitor vehicle main menu which also showed a similar graphic. Strangely the 'calibrate' option was greyed out and unavailable.

Early this morning (whilst cool) I used a gauge to check and found that all tyres were very close to the figures on the door plate (actually both nearside tyres were a fraction high). I've now set them all to exactly the recommended pressure.

I've not actually used the car today so I don't know if the problem is still there. But why did this happen?

I once had this occur, but there was no tyre damage. You did the right thing by checking pressures when cool. Once checked, you need to re-calibrate and all should be OK. It certainly does work when you do get a slow puncture. I reckon a drop of about 20% from the normal in the affected tyre triggers the monitor. If the problem persists, get it checked.

How did you re-calibrate when that option was greyed out?

None of my tyres had lost pressure.

The light can come on even if all the tyres are at the same pressure. For instance, if you change from light load settings (say 36psi) to economy (39psi) and don't re-calibrate then the light can come on.
To complicate matters it doesn't necessarily come on straight away, e.g. I have changed from winter to summer wheels/tyres, driven around the village for a few days with no problem and then hit the motorway and twenty minutes later the light has come on. Quick pressure test and all 4 tyres are the same, recalibrated, and next time I saw the warning light was after changing back from summer wheels/tyres to the winter ones.
There is no special sensor in the tyres (like there used to be). The TPMS now works off rolling circumference and compares across all four corners and from data history.
If your calibrate button was greyed out, and I'm guessing, maybe you have to leave the car cool down or switch engine off? Check your owners manual is the best advice.

Maybe the hot day and long journey served to increase the pressure and confuse the monitoring system? Strange though, with no significant differential changes. If this is going to happen then I'd rather disable it!

The paper owners manual is useless on this subject. The on-board e-version does give some information (including an explanation of the differences between TPMS and this simplified 'tyre monitoring' system) but doesn't cover what situations might give the sort of false/nuisance alarm that I've experienced.

If you go to here:
https://www.volvocars.com/uk/support...20&tab=manuals

Fill in the boxes for car model and MY (you will find the specific MY for your car, as there are often 2 for each year, by looking at the back cover of the paper owners manual you already have).
When you click OK scroll to the bottom of the page and you will see a list of pdf manuals available for your specific car. Note that the pdf owners manual is (almost definitely) much more detailed than the one provided in the car (around 450 pages).

I have a pdf copy on phone and tablet - the app is also OK but I am old school and prefer to go to the index and work back from there (the pdf is linked so you can just click on the index, or contents, subject line or page number and it will jump directly there)

It was greyed out because you are moving , try it when stopped .

Just returned from driving.

The 'calibrate' function had remained greyed out and the wheels all amber when I set off. I pushed 'OK' several times without success whilst moving but when my wife pushed it whilst stopped then the system went into calibration (despite being still greyed out) and all wheels went green. I believe it now has to monitor the relative wheels rotations for 30km before updating its internal baseline figure.

I'd keep watching it but I've also inserted a map update USB stick which has taken over the display!

Just had a look in my manual and it is probably 'greyed out' because you are meant to do it with ignition on (key position II) but engine off. Same as if you were measuring your oil, etc.

I get a similar thing maybe once or twice a year. It just seems to be one of those random glitches.

Mine has the sensors in the tyres, not sure which model year it changed. I assumed it was something to do with temporary interference of the presssure transmitter.