2020 Ram 4500 Chassis Cab Tank

198STARTING AND OPERATING
Idle-Up Feature
The driver-controlled high idle speed feature will
help increase cylinder temperatures and
provide additional cab heat, however, excessive
idling may still cause the exhaust aftertreat -
ment system to not properly regenerate.
Extended periods of idle time should be
avoided.
The Idle-Up feature uses the Speed Control
switches to increase engine idle speed and
quickly warm the vehicle's interior.

1. With the transmission in PARK, the parking brake applied, and the engine running,
turn on the speed control, then push the
SET switch.

2. The engine RPM will go up to 1,100 RPM. To increase the RPM, push and hold the
ACCEL/RESUME switch and the idle speed
will increase to approximately 1,500 RPM.
To decrease the RPM, push and hold the
DECEL switch and the idle speed will
decrease to approximately 1,100 RPM.
3. To cancel the Idle–Up feature, either push the CANCEL switch, push the ON/OFF
switch, or press the brake pedal.
Noise
Diesel engines can create noises that may
seem as a concern. The nature of a diesel
engine is compression ignition where
compressed air and fuel are mixed and ignited.
Weather, Barometric Pressure, Altitude and
Temperature will affect how fuel is ignited in the
engine. Engine’s will sound different from day to
day or previous model years. Clicking, ticking, or
light knocking is normal and will change from
day to day, as the engine breaks in, and can
vary with changes in ambient temperature, this
is normal. Diesel equipped vehicles also have
an exhaust aftertreatment system to reduce
emissions utilizing a Diesel Particulate Filter
(DPF) and a Selective Reduction Catalyst (SCR).
The SCR reduces Nox using the Diesel Exhaust
Fluid (DEF) system. DEF is injected directly into
the SCR through an dosing module. This
process will create a clicking sound and at
times, will make noise even with the vehicle shut off. This is normal as the DEF dosing
module is purging DEF. Fuel pump noise may
increase during low speed/light load conditions
when ambient temperature is above 100°F
(38°C), and when fuel tank level is below 10%.
This is a normal condition of the fuel system and
controls strategy. If at any time the check
engine light is on, please visit an authorized
dealer.
Stopping The Engine
Idle the engine a few minutes before routine
shutdown. After full load operation, idle the
engine three to five minutes before shutting it
down. This idle period will allow the lubricating
oil and coolant to carry excess heat away from
the combustion chamber, bearings, internal
components, and turbocharger. This is espe
-
cially important for turbocharged, charge
air-cooled engines. Refer to the following chart
for proper engine shutdown:

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268STARTING AND OPERATING
REFUELING THE VEHICLE — GAS ENGINENOTE:
When the fuel nozzle “clicks” or shuts off the
fuel tank is full.
NOTE:
Tighten the gas cap a quarter turn until you hear
one click. This is an indication that the cap is
properly tightened.
If the gas cap is not tightened properly, the
Malfunction Indicator Light will come on. Be
sure the gas cap is tightened every time the
vehicle is refueled.
Loose Fuel Filler Cap Message
If the vehicle diagnostic system deter -
mines that the fuel filler cap is loose,
improperly installed, or damaged, a
loose gASCAP indicator will display in
the instrument cluster telltale display area.
Refer to “Instrument Cluster Display” in
“Getting To Know Your Instrument Panel” for
further information. Tighten the fuel filler cap
properly and push the RIGHT button to turn off
the message. If the problem continues, the
message will appear the next time the vehicle is
started.
CAUTION!
Damage to the fuel system or emissions
control system could result from using an
improper fuel tank filler tube cap (fuel filler
cap). A poorly fitting cap could let impurities
into the fuel system. Also, a poorly-fitted
aftermarket cap can cause the MIL
(Malfunction Indicator Light) to illuminate
due to fuel vapors escaping from the
system.
A poorly fitting fuel filler cap may cause the
MIL to turn on.
To avoid fuel spillage and overfilling, do not
“top off” the fuel tank after filling.
WARNING!
Never have any smoking materials lit in or
near the vehicle when the gas cap is
removed or the tank is being filled.
Never add fuel to the vehicle when the
engine is running. This is in violation of
most state and federal fire regulations and
may cause the MIL to turn on.
WARNING!
A fire may result if gasoline is pumped into a
portable container that is inside of a vehicle.
You could be burned. Always place gas
containers on the ground while filling.

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STARTING AND OPERATING269
REFUELING THE VEHICLE — DIESEL ENGINE
NOTE:
When the fuel nozzle “clicks” or shuts off, the
fuel tank is full.
Tighten the fuel filler cap until you hear a
“clicking” sound. This is an indication that the
fuel filler cap is properly tightened.
Make sure that the fuel filler cap is tightened
each time the vehicle is refueled.
Fuel Filler Cap
If the fuel filler cap is lost or damaged, be sure
the replacement cap is for use with this vehicle.
Avoid Using Contaminated Fuel
Fuel that is contaminated by water or dirt can
cause severe damage to the engine fuel
system. Proper maintenance of the engine fuel
filter and fuel tank is essential. Refer to “Dealer
Service” in “Servicing And Maintenance” for
further information.
Bulk Fuel Storage — Diesel Fuel
If you store quantities of fuel, good mainte -
nance of the stored fuel is also essential. Fuel
contaminated with water will promote the
growth of “microbes.” These microbes form
“slime” that will clog the fuel filtration system
and lines. Drain condensation from the supply
tank and change the line filter on a regular
basis.
NOTE:
When a diesel engine is allowed to run out of
fuel, air is pulled into the fuel system.
If the vehicle will not start, refer to “Priming If
The Engine Has Run Out Of Fuel” in “Servicing
And Maintenance” for further information.CAUTION!
To avoid fuel spillage and overfilling, do not
“top off” the fuel tank after filling.
WARNING!
A fire may result if gasoline is pumped into a
portable container that is inside of a vehicle.
You could be burned. Always place gas
containers on the ground while filling.
WARNING!
Never have any smoking materials lit in or
near the vehicle when the fuel filler cap is
removed or the tank filled.
Never add fuel to the vehicle when the
engine is running.
CAUTION!
Damage to the fuel system or emission
control system could result from using an
improper fuel tank filler tube cap. A poorly
fitting cap could let impurities into the fuel
system.
WARNING!
Do not open the high pressure fuel system
with the engine running. Engine operation
causes high fuel pressure. High pressure fuel
spray can cause serious injury or death.
5

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270STARTING AND OPERATING
Diesel Exhaust Fluid
Your vehicle is equipped with a Selective Cata-
lytic Reduction (SCR) system to meet the very
stringent diesel emissions standards required
by the Environmental Protection Agency.
The purpose of the SCR system is to reduce
levels of NOx (oxides of nitrogen emitted from
engines) that are harmful to our health and the
environment to a near-zero level. A small quan -
tity of Diesel Exhaust Fluid (DEF) is injected into
the exhaust upstream of a catalyst where, when
vaporized, it converts smog-forming nitrogen
oxides (NOx) into harmless nitrogen (N2) and
water vapor (H2O), two natural components of
the air we breathe. You can operate with the
comfort that your vehicle is contributing to a
cleaner, healthier world environment for this
and generations to come.
System Overview
This vehicle is equipped with a Diesel Exhaust
Fluid (DEF) injection system and a Selective
Catalytic Reduction (SCR) catalyst to meet the
emission requirements. The DEF injection system consists of the
following components:
DEF tank
DEF pump
DEF injector
Electronically-heated DEF lines
DEF control module
NOx sensors
Temperature sensors
SCR catalyst
UQS Sensor
Refer to “Instrument Cluster Display” in
“Getting To Know Your Instrument Panel” for
system messages and warnings.
NOTE:
Your vehicle is equipped with a DEF injection
system. You may occasionally hear an
audible clicking noise. This is normal opera -
tion.
The DEF pump will run for a period of time
after engine shutdown to purge the DEF
system. This is normal operation.
Diesel Exhaust Fluid Storage
Diesel Exhaust Fluid (DEF) is considered a very
stable product with a long shelf life. If DEF is
kept in temperatures between 10° and 90°F
(-12° and 32°C), it will last a minimum of one
year.
DEF is subject to freezing at the lowest tempera-
tures. For example, DEF may freeze at tempera-
tures at or below 12°F (-11°C). The system has
been designed to operate in this environment.
NOTE:
When working with DEF, it is important to know
that:
Any containers or parts that come into
contact with DEF must be DEF compatible
(plastic or stainless steel). Copper, brass,
aluminum, iron or non-stainless steel should
be avoided as they are subject to corrosion
by DEF.
If DEF is spilled, it should be wiped up
completely.

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STARTING AND OPERATING271
Adding Diesel Exhaust Fluid (DEF)
The DEF gauge (located on the instrument
cluster) will display the level of DEF remaining in
the tank. Refer to “Instrument Cluster” and
“Instrument Cluster Descriptions” in “Getting To
Know Your Instrument Panel” for further infor -
mation.
NOTE:
Driving conditions (altitude, vehicle speed,
load, etc.) will effect the amount of DEF that
is used in your vehicle.
Another factor is that outside temperature
can affect DEF consumption. In cold condi -
tions, 12°F (-11°C) and below, the DEF
gauge needle can stay on a fixed position and
may not move for extended periods of time.
This is a normal function of the system.
There is an electric heater inside the DEF
tank that automatically works when neces -
sary. And if the DEF supply does freeze, the
truck will operate normally until it thaws.
DEF Fill Procedure
NOTE:
Refer to “Fluids And Lubricants” in “Technical
Specifications” for the correct fluid type.

1. Remove cap from DEF tank (located on
drivers side of the vehicle or in fuel door).

DEF Filler Cap And Fuel Fill Chassis Cab Models

2. Insert DEF fill adapter/nozzle into DEF tank filler neck. NOTE:The DEF gauge may take up to five seconds
to update after adding a gallon or more of
Diesel Exhaust Fluid (DEF) to the DEF tank.
If you have a fault related to the DEF
system, the gauge may not update to the
new level. See an authorized dealer for
service.
The DEF gauge may also not immediately
update after a refill if the temperature of the
DEF fluid is below 39°F (4°C). The DEF line
heater will possibly warm up the DEF fluid
and allow the gauge to update after a period
of run time. Under very cold conditions, it is
possible that the gauge may not reflect the
new fill level for several drives.
Excessive overfilling of the DEF tank can
result in a MIL lamp/fault code and inaccu
-
rate level readings.1 — Diesel Exhaust Fluid (DEF) Fill Location
2 — Diesel Fuel Fill Location
5

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272STARTING AND OPERATING
(Continued)
3. Stop filling the DEF tank immediately when any of the following happen: DEF stops
flowing from the fill bottle into the DEF tank,
DEF splashes out the filler neck, or a DEF
pump nozzle automatically shuts off.
4. Reinstall cap onto DEF tank. Filling The Def Tank In Cold Climates
Since DEF will begin to freeze at 12°F (-11°C),
your vehicle is equipped with an automatic DEF
heating system. This allows the DEF injection
system to operate properly at temperatures
below 12°F (-11°C). If your vehicle is not in
operation for an extended period of time with
temperatures below 12°F (-11°C), the DEF in
the tank may freeze. If the tank is overfilled and
freezes, it could be damaged. Therefore, do not
overfill the DEF tank.

Extra care should be taken when filling with
portable containers to avoid overfilling. Note the
level of the DEF gauge in your instrument cluster.
You may safely add a maximum of 2 gallons
(7.5 liters) of DEF from portable containers when
your DEF gauge is reading ½ full.

CAUTION!
To avoid DEF spillage, and possible
damage to the DEF tank from overfilling, do
not “top off” the DEF tank after filling.
DO NOT OVERFILL. DEF will freeze below
12ºF (-11ºC). The DEF system is designed
to work in temperatures below the DEF
freezing point, however, if the tank is over
-
filled and freezes, the system could be
damaged.
When DEF is spilled, clean the area imme -
diately with water and use an absorbent
material to soak up the spills on the ground.
Do not attempt to start your engine if DEF is
accidentally added to the diesel fuel tank
as it can result in severe damage to your
engine, including but not limited to failure
of the fuel pump and injectors.
Never add anything other than DEF to the
tank – especially any form of hydrocarbon
such as diesel fuel, fuel system additives,
gasoline, or any other petroleum-based
product. Even a very small amount of these,
less than 100 parts per million or less than
1 oz. per 78 gallons (295 liters) will contam -
inate the entire DEF system and will require
replacement. If owners use a container,
funnel or nozzle when refilling the tank, it
should either be new or one that is has only
been used for adding DEF. Mopar provides
an attachable nozzle with its DEF for this
purpose.
CAUTION! (Continued)

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IN CASE OF EMERGENCY311
F68 –10 Amp Red AEB RACAM HTR – If Equipped (HD Only)
F69 –15 Amp Blue SCR Module – If Equipped (HD Only)
F70 –30 Amp GreenFuel Pump Motor / K09 RLY Coil Feed (Cummins Diesel) –
If Equipped
F71 –25 Amp ClearAmplifier / Active Noise Cancelation – If Equipped (HD
Only)
F72 –10 Amp RedPCM / DC/DC Converter Voltage– If Equipped (DS 1500
Only)
F73 –20 Amp Yellow Fuel Transfer Pump (Rear Tank) – If Equipped (HD Only)
F74 –20 Amp Yellow Brake Vacuum Pump Gas/Diesel – If Equipped (DS 1500
Only)
F74 –10 Amp Red Backup Alarm – If Equipped (HD Only)
F75 –10 Amp RedATMM / Coil-SCR Module RLY– If Equipped (HD Only)
Coolant Temperature Valve – If Equipped (DS 1500 Only)
F76 –10 Amp RedElectronic Stability Control (HD Only)
Brake System Module / Stop Lamp Switch / Electric Park
Brake / Clutch Pedal Switch (DS 1500 Only)
F77 –10 Amp Red
Drivetrain Control Module / Front Axle Disconnect Module /
TCM/ STOM (HD Only)

Drivetrain Control Module / ELSD / Front Axle Disconnect
Module / Transmission Control Relay / RDM / Power Take
Off Unit – If Equipped (DS 1500 Only)
Cavity
Cartridge Fuse Micro Fuse Description
6

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336SERVICING AND MAINTENANCE
Maintenance Plan — Cummins Diesel Engine
Mileage or time passed
(whichever comes first):
7,500
15,000
22,500
30,000
37,500
45,000
52,500
60,000
67,500
75,000
82,500
90,000
97,500
105,000
112,500
120,000
127,500
135,000
142,500
150,000
Or Months:6
12
18
24
30
36
42
48
54
60
66
72
78
84
90
96
102
108
114
120
Or Kilometers:
12,000
24,000
36,000
48,000
60,000
72,000
84,000
96,000
108,000
120,000
132,000
144,000
156,000
168,000
180,000
192,000
204,000
216,000
228,000
240,000
Change engine oil every
15,000 miles (24,000 km) or
12 months or 500 hours or
sooner if prompted by the oil
change indicator system,
whichever comes first.
1
X X X X X X X X X X
Additional Inspections
Check the Diesel Exhaust Fluid
(DEF) tank, refill if necessary. X X X X X X X X X X X X X X X X X X X X
Rotate the tires. X X X X X X X X X X X X X X X X X X X X
Inspect the CV/Universal joints. X X X X X X X X X X X X X X X X X X X X
Inspect front end, and lubricate
— If equipped with serviceable
fittings. X
X X X X X X X X X X X X X X X X X X X

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