and close to odorless (it may have a slightly pungent
odor similar to ammonia). It is nontoxic, nonflam-
mable, and biodegradable. It is mildly corrosive to
aluminum, but does not affect the strength or struc-
ture of the aluminum.
White crystals may be noticeable around compo-
nents that come into contact with DEF. The crystals
are easily removed with water.
DEF consumption varies depending on ambient con-
ditions and vehicle application.
Freezing Conditions
DEF freezes to slush at around 12°F (-11°C). It is not
damaged or destroyed if frozen, and is fully usable
when thawed. The DEF in the tank is allowed to
freeze while a vehicle is non-operational. At start-up,
normal operation of the vehicle is not inhibited if the
DEF is frozen; an immersion heater with engine cool-
ant flowing through it warms the DEF once the en-
gine is running, allowing the SCR system to operate.
DEF Tank
Engines that are compliant with EPA10 and newer
regulations are equipped with a DEF tank located on
the driver’s side of the vehicle behind the battery box
or forward of the fuel tank. The DEF tank has a 19
mm filler neck inlet that prevents the hose from a
diesel outlet from being inserted, and has a blue cap
for easy identification.
Fuel/DEF Gauge
The diesel fuel and DEF levels are measured in a
dual-purpose gauge. Below the gauge, a low fuel
warning lamp illuminates amber when the fuel level
drops below 1/8th of the capacity. See
Fig. 14.7.
A DEF warning lamp illuminates amber when the
DEF tank is near empty.
DEF Warnings and Engine Limits
IMPORTANT: Ignoring the DEF low level warn-
ings results in limited engine power, with the
application of a 5 mph (8 km/h) speed limit.
DEF Level Low—Initial Warning
When the DEF level is low, the DEF warning lamp
illuminates solid amber, and the driver display screen
presents an alert. See
Fig. 14.8. Refill the DEF tank
in order to cancel the warning sequence.
DEF Empty
When the DEF level reads empty, the following
lamps and messages notify the driver.
•
The DEF warning lamp flashes amber.
•
The MIL lamp illuminates.
•
The driver display screen presents the warn-
ing, "DEF Tank Empty." See Fig. 14.8.
Power is limited with progressively harsher engine
power limits applied.
DEF Tank Empty and Ignored
If the empty warning is ignored and the DEF tank is
not refilled, the red STOP engine lamp illuminates in
addition to the MIL lamp and CHECK engine lamp
(on vehicles with a Cummins ISB or ISC/L engine).
If the DEF is not refilled, a 5 mph (8 km/h) speed
limit is applied after the next engine shutdown, while
parked and idling, or if a fuel refill is detected.
DEF Contamination or SCR Tampering
NOTICE
Once contaminated DEF or tampering has been
detected, the vehicle must be taken to an autho-
rized service facility to check the SCR system for
f61140906/28/2016
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2
43
1. Fuel Gauge Pointer
2. DEF Gauge Pointer
3. Low Fuel Level Warning Lamp
4. Low DEF Level Warning Lamp
Fig. 14.7, Fuel/DEF Gauge
Emissions and Fuel Efficiency
14.8
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