tyre pressure alert

[bigwave2255]

hmmmm, first time ive seen this, driving to work this morning the tyre alert goes off, red symbol on dash and tone.

so i stop get out and check the tyres, do the thumb pressure test, and all seemed ok.

got back in and started the car, warning light still on, so i pressed the button and held it for a couple of seconds, it went yellow and then went off, and the warning hasn't reappeared.

on my driveway at home the sun in the morning hits the right hand side of the car and the left hand side is in shade, and as we had a quite cool night i wonder if the tyre pressures went up on the side in the sun, and that variation, when compared with the cold tyres on the left hand side was enough to set it off ??.

another possibility is that i didn't realise that i was supposed to do a re initialisation once new tyre are fitted, so maybe that was it

any thoughts???/