JLG 1500SJ Operator Manual - Manual (Page 103)

SECTION 5 - LCD DISPLAY PANEL - GENERATION 1 & 2
3121261 – JLG Lift – 5-7
Conditional Icons
Several icons exist which may display below the line on the LCD
panel on any screen if the operating condition they represent
exists. These icons are Jib Unlocked, Jib Locked, Reduced Speed
(turtle), Creep Speed (snail), Fault Code, Safety Alert Symbol, and
No Serviceable Faults Present (check mark).