Porsche Boxster Owner's Manual page 160

6. If the segments are filled in up to the top line,
the oil level has reached the maximum mark.
Under no circumstances add engine oil.
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Instruments, On-Board Computer, Warnings
7. If the bottom segment is filled in, the oil level
has reached the minimum mark.
Add engine oil immediately.
8. If the bottom segment flashes, the oil level has
dropped to below the minimum mark.
Add engine oil immediately.
The difference between the minimum and
maximum marks on the segment display is
approx. 1.3 quarts (1.25 litres).
One segment of the display corresponds to a
top-up quantity of approx. 0.42 quarts (0.4 litre).
f Add engine oil if necessary.
Switch off ignition before adding engine oil.
f Please see the chapter "ENGINE OIL LEVEL"
on Page 199.
f Never add more engine oil than required
to reach the maximum mark.
Failure
A failure of the oil level display is indicated by a
warning message on the on-board computer.
"Check engine oil level" display
The on-board computer display "Check engine oil
level" is an additional measurement that takes
place in the background while driving.
The display depends on the distance travelled.
This display appears if the oil level has reached the
minimum mark or if the oil level is well above the
maximum mark.
This message must be acknowledged by measu-
ring the engine oil level manually using the on-
board computer.
f Please see the chapter "INITIATING OIL LEVEL
MEASUREMENT" on Page 157.
If an oil level measurement was initiated manually
on the on-board computer and no oil was topped
up, the message "Check engine oil level" is
displayed again when the vehicle is driven.