Navistar ProStar+ Operation And Maintenance Manual page 90

Controls / Features
Quadrant 2 – Display
Messages
DEF Quality Derated
DEF Quality Derated 5mph
78
Description
Diesel Exhaust Fluid (DEF) quality problem has been
present for 1 hour or longer. Engine performance is limited.
Diesel Exhaust Fluid (DEF) quality problem has been
present for 3 hours or longer. Engine performance is
limited and vehicle speed is limited to 5 mph (8 km/h).
Message Flashes (Yes Warning Indicator
/ No) Association
No Amber Warning Lamp
No Amber Warning Lamp;
Red Stop Lamp