greens_peace

From the manual. I have to type blue and red as the icon does not come through in the paste. If you get one ping on a cold morning it could just be telling you that the outside temperature is below 4 degrees C if this is so the outside temp will flash
 
Coolant temperature/coolant quantity  
The warning light Blue lights up until the engine reaches operating temperature3).
Avoid running at high engine speeds, at full throttle and at severe engine loads.
The warning light red comes on for a few seconds when the ignition is switched on.
The coolant temperature is too high or the coolant level too low if the warning light
red lights up or flashes while driving.
An audible signal sounds as an additional warning signal.
In this case stop and switch the engine off and check the coolant level; top up the
coolant as necessary  page 158, “Replenishing the coolant”.
Do not continue your journey if for some reason it is not possible under the conditions
prevailing to top up with coolant. Keep the engine switched off and obtain
professional assistance from a specialist garage, otherwise it could lead to severe
engine damage.
If the coolant is within the specified range, the increased temperature may be
caused by an operating problem at the coolant fan. Check the fuse for the coolant
fan, replace it if necessary  page 185, “Fuse assignment at the battery (manual
gearbox, automatic gearbox DSG)”.
If the warning light red does not go out although the coolant is at the correct level
and also the fuse of the fan is in proper order, do not continue driving. Contact a
specialist garage to obtain assistance.
Please refer to the following guidelines  page 157, “Cooling system”.
The following text will be displayed in the information display:
Check coolant! Owner's manual!
 
Outside temperature
The outside temperature appears in the display when the ignition is switched on.
If the outside temperature drops below +4 °C, a snow flake symbol (warning signal
for ice on the road) appears in front of the temperature indicator and flashes for 10
seconds, then remains displayed together with the outside temperature. At the
same time an audible signal sounds. After pressing the rocker switch on the
windshield wiper lever