Lexmark Optra C Service Manual page 121

5045-001
2. Decide on a test print pattern by using the + key or - key. When
the test print pattern differs from that currently selected in the
printer, the Density gauge LED will flash. The correspondence
between the Density gauge LEDs and each test print pattern is
as follows.
3. Determine the test print pattern by the ENTER key. The Density
gauge LED lights and the print test pattern changes.
Diagnostic Aids 3-16