• SCR Temperature Sensor
• Ammonia Sensor
Temperature Sensor before DOC
– This sensor
monitors the gas temperature that is entering the
DOC
NOx Sensor
– Two NOx sensors monitor the NOx
concentration within the exhaust gas before and after
the SCR module.
SCR Temperature Sensor
– The sensor monitors
the gas temperature entering the SCR.
Ammonia Sensor
– The sensor monitors the
concentration of ammonia within the exhaust system
after the CEM.
The temperature sensor before DOC, NOx sensor,
SCR temperature sensor, and ammonia sensor all
connect with the engine ECM. If the signal from these
sensors is out of the set range, the ECM will trigger
an alarm for the operator.
DOC, SCR, and DPF System
Temperature Sensor before DOC
– This sensor
monitors the gas temperature as the gas enters the
DOC
DPF Temperature Sensor
– The temperature
sensor monitors the temperature within the DPF.
Soot Sensor Control
– The soot sensor control unit
monitors the amount of soot within the DPF.
NOx Sensor
– Two NOx sensors monitor the NOx
concentration within the exhaust gas before and after
the SCR module.
SCR Temperature Sensor
– The sensor monitors
the gas temperature entering the SCR.
The temperature sensor before DOC, DPF
temperature sensor, soot sensor, NOx sensor, SCR
temperature sensor, and ammonia sensor all
connected to the ECM. If the signal from these
sensors is out of the set range, the ECM will trigger
an alarm for the operator.
Diesel Exhaust Fluid (DEF) System
Control
DEF Level Sensor
– The DEF level sensor signals
the ECM. The ECM determines the signal in order to
give a level reading of the volume of fluid in the tank.
DEF Temperature Sensor
– The sensor signals the
ECM. The ECM will determine the temperature of the
DEF within the tank from the signals sent. The
temperature of the DEF is important in order to keep
the DEF injector operation correctly.
Dosing Control Unit (DCU)
– The DCU controls the
injection of the DEF and will signal the ECM if the
injection has been interrupted.
The DEF level sensor, DEF temperature sensor, and
the Dosing control unit all connect with the engine
ECM. If the ECM determines that any of the signals
are out of the specified range, an alarm will be
triggered.
Testing
Turning the keyswitch to the ON position will check
the indicator lights on the control panel. All the
indicator lights will be illuminated for 2 seconds after
the keyswitch is operated. Replace suspect bulbs
immediately.
Refer to Troubleshooting for more information.
i07272862
Selective
Catalytic
Reduction
Warning
System
The
Selective
Catalytic
Reduction
(SCR)
system
is
a
system
used
to
reduce
NOx
emissions
from
the
engine.
Diesel
Exhaust
Fluid
(DEF)
is
pumped
from
the
DEF
tank
and
is
sprayed
into
the
exhaust
stream.
The
DEF
reductant
is
stored
on
the
catalyst
and
reduces
NOx,
leaving
nitrogen
gas
and
water
vapor.
NOTICE
Stopping the engine immediately after the engine has
been working under load can result in overheating of
DEF system components.
Refer to the Operation and Maintenance Manual,
“Engine Stopping” procedure to allow the engine to
cool and to prevent excessive temperatures in the
turbocharger housing and the DEF injector.
NOTICE
Allow the engine to perform a DEF purge of the DEF
system before you turn the battery disconnect switch
to OFF. Disconnecting the battery power too soon
may prevent purging of the DEF lines after the engine
is shutdown. Refer to this Operation and Mainte-
nance Manual, “Battery Disconnect Switch” for more
information.
Warning Strategy
The Electronic Control Module (ECM) will be enabled
with a world-wide warning strategy.
Warning Indicators
The warning indicators consist of a level gauge for
the DEF, a low-level lamp for the DEF, and emission
malfunction lamp. Also, an application stop lamp.
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