Operators Manual

Table Of Contents
EPA10 Diesel Exhaust Fluid (DEF) Purge Cycle
For EPA10 only, the DEF purge cycle is used to protect the DEF system from
freezing. The purge cycle starts right after the key is shut off. The vehicle's air
system is used to evacuate excess DEF from the DEF metering unit and nozzle
supply hose. During the purge cycle, air can be heard leaking, which should not be
mistaken as a leak. It is normal for the air pressure gauge to drop 9 to 12 psi during
this routine with the engine off.
NOTE: For trucks equipped with negative battery disconnect, do not turn
the battery disconnect switch off until the purge light (located on the battery
disconnect switch) turns off.
DD Heavy Duty Platform Operators Manual
All information subject to change without notice. 93
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