freightliner Custom Classic MT45 2022, Maintenance Manual

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49–00 Safety Precautions
Safety Precautions in this section apply to all
procedures within this group.
DANGER
When working on the vehicle, shut down the en-
gine or motor, set the parking brake, and chock
the tires. Before working under the vehicle, always
place jack stands under the frame rails to ensure
the vehicle cannot drop. Failure to follow these
steps could result in serious personal injury or
death.
49–01 Exhaust System
Inspecting (Noise
Emission Control)
The exhaust system must be free of leaks, binding,
grounding, and excessive vibrations. In addition to
inspecting the exhaust system at the scheduled
maintenance interval, inspect the exhaust system if
the noise level of the vehicle has increased. Replace
parts that show leakage, wear, or damage, with
genuine Freightliner parts.
These conditions are usually caused by loose, bro-
ken, or misaligned clamps, brackets, or pipes. If any
of these conditions exist, check the exhaust system
components and alignment. Align or replace as nec-
essary. For alignment or adjustment instructions, see
Group 49 of the Walk-In Van Chassis Workshop
Manual , or take the vehicle to an authorized Freight-
liner dealer.
EPA10 and Newer Exhaust
System
Definitions of Aftertreatment
System (ATS) Terms
Refer to the following list of definitions of ATS terms
and components.
•
Aftertreatment System (ATS)—the entire ex-
haust system from the turbocharger to the tail
pipe, including the Selective Catalytic Reduction
(SCR) components.
•
Aftertreatment Device (ATD)—a device that re-
moves pollutants from exhaust gas after the gas
leaves the combustion chamber.
•
BlueTec®—Daimler’s proprietary SCR technol-
ogy.
•
Diesel Oxidation Catalyst (DOC)—a flow-
through device that enhances the oxidation of
hydrocarbons in the ATD.
•
Diesel Particulate Filter (DPF)—a component in
the ATD that traps particulate matter from the
exhaust gas.
•
Diesel Exhaust Fluid (DEF)—the chemical agent
that reacts with the exhaust gases in the SCR
to reduce NOx.
•
DEF Pump—filters and supplies DEF to the
DEF metering unit.
•
DEF Tank—holds DEF and regulates its tem-
perature.
•
DEF Metering Unit—mixes DEF with com-
pressed air, and meters this mixture into the
exhaust flow via an injection nozzle.
•
SCR Catalyst—the housing containing a treated
ceramic flow-through block where the DEF and
exhaust gases undergo selective catalytic re-
duction.
•
Selective Catalytic Reduction (SCR)—a process
used to reduce NOx emissions.
Inspection
IMPORTANT: The Environmental Protection
Agency’s 2010 regulations mandate lowered
exhaust emissions, thus requiring exhaust sys-
tem components that reduce emissions. In par-
ticular the aftertreatment device (ATD), which is
part of the aftertreatment system (ATS), requires
special attention during regularly scheduled
maintenance inspections. See
Fig. 1 for Cum-
mins ATD sensor locations. The side-by-side
mounting is shown, however, left inline and top
side-by-side mountings are possible depending
on the chassis design. If any discrepancies are
discovered, refer to the engine manufacturer’s
service literature for repair instructions.
1. Check for leakage at the clamp that attaches the
exhaust pipe to the turbocharger exhaust outlet.
If leakage exists, tighten the nut on the clamp to
Exhaust
49
Walk-In Van Chassis Maintenance Manual, November 2015
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