light RAM CHASSIS CAB 2021 Owners Manual

SERVICING AND MAINTENANCE379
Use of biodiesel mixture in excess of 20% can
negatively impact the fuel filter's ability to
separate water from the fuel, resulting in
high pressure fuel system corrosion or
damage.
Ethanol blends are not recommended or
approved for use with your Cummins diesel
engine.
In addition, commercially available fuel addi -
tives are not necessary for the proper opera -
tion of your Cummins diesel engine.
INTERVENTION REGENERATION
S
TRATEGY — MESSAGE PROCESS FLOW
The Cummins diesel engine meets all
Environmental Protection Agency (EPA) Heavy
Duty Diesel Engine Emissions Standards,
resulting in one of the lowest emitting diesel
engines ever produced.

To achieve these emissions standards, your
vehicle is equipped with a state-of-the-art engine
and exhaust system. The engine and exhaust
after-treatment system work together to achieve
the EPA Heavy Duty Diesel Engine Emissions
Standards. These systems are seamlessly
integrated into your vehicle and managed by the Cummins Powertrain Control Module (PCM).
The PCM manages engine combustion to allow
the exhaust system’s catalyst to trap and burn
Particulate Matter (PM) pollutants, with no input
or interaction on your part.
If the engine is allowed to idle or the truck is
driven on low engine speed drive cycles for more
than two hours, the system will automatically
enter an emissions operating mode that will
increase the engine idle speed to 900 RPM
(1,050 RPM for Chassis Cab). While in this mode,
which is designed to help maintain the Diesel
Particulate Filter, the engine idle speed will return
to normal when the brake pedal is applied.
A small change in engine tone or a slight change
in engine performance while accelerating may
also be noticeable at speeds below 20 mph
(32 km/h). This operating mode may last for up
to an hour of idle time, or around 20 minutes of
driving time.

Additionally, your vehicle has the ability to alert
you to additional maintenance required on your
truck or engine Ú
page 90.
DIESEL EXHAUST FLUID
Diesel Exhaust Fluid (DEF) sometimes known
simply by the name of its active component,
UREA—is a key component of Selective Catalytic
Reduction (SCR) systems, which help diesel
vehicles meet stringent emission regulations.
DEF is a liquid reducing agent that reacts with
engine exhaust in the presence of a catalyst to
convert smog-forming nitrogen oxides (NOx)
into harmless nitrogen and water vapor
Úpage 440.
You can receive assistance in locating DEF in
the United States by calling 866-RAM-INFO
(866-726-4636). In Canada call
1–800–465–2001 (English) or
1–800–387–9983 (French)
WARNING!
A hot exhaust system can start a fire if you
park over materials that can burn. Such
materials might be grass or leaves coming
into contact with your exhaust system. Do not
park or operate your vehicle in areas where
your exhaust system can contact anything
that can burn.
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SERVICING AND MAINTENANCE391
Lubricant Selection
For further information Úpage 444.
NOTE:

The presence of water in the gear lubricant will
result in corrosion and possible failure of differ -
ential components. Operation of the vehicle in
water, as may be encountered in some
off-highway types of service, will require draining
and refilling the axle to avoid damage.

Limited-Slip Differentials DO REQUIRE limited
slip oil additive (friction modifiers).
NOTE:
Slight noise and mild shuddering may be
evident while turning a vehicle with limited
slip differential on concrete or dry pavement.
These conditions should be considered normal
operation of the limited slip differential.
TRANSFER CASE
Fluid Level Check
This fluid level can be checked by removing the
filler plug. The fluid level should be to the
bottom edge of the filler plug hole with the
vehicle in a level position.
Drain And Refill
For the proper maintenance intervals
Ú page 354.
Selection Of Lubricant
Use only the manufacturer's recommended
fluid Ú page 444.
NOISE CONTROL SYSTEM REQUIRED
M
AINTENANCE & WARRANTY

All vehicles built over 10,000 lbs. (4,535 kg) Gross
Vehicle Weight Rating and manufactured for sale
and use in the United States are required to comply
with the Federal Government's Exterior Noise
Regulations. These vehicles can be identified by
the Noise Emission Control Label located in the
operator's compartment.

Required Maintenance For Noise Control
Systems
The following maintenance services must be
performed every six months or 7,500 miles
(12,000 km) whichever comes first, to ensure
proper operation of the noise control systems.
In addition, inspection and service should be
performed anytime a malfunction is observed or
suspected. Proper maintenance of the entire
vehicle will help the effectiveness of the noise
control systems.
Exhaust System
Inspect the entire exhaust system for leaks and
damaged parts. Devices such as hangers,
clamps, and U-bolts should be tight and in good
condition. Damaged components, burned or
blown out mufflers, burned or rusted out
exhaust pipes should be replaced according to
the procedures and specifications outlined in
the appropriate service manual.
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SERVICING AND MAINTENANCE395
Power Distribution Center
The Power Distribution Center is located in the
engine compartment near the battery. This
center contains cartridge fuses, micro fuses,
relays, and circuit breakers. A description of
each fuse and component may be stamped on
the inside cover, otherwise the cavity number of
each fuse is stamped on the inside cover that
corresponds to the following chart.

Power Distribution Center Location

Cavity Cartridge FuseMicro Fuse Description
F01– –Spare
F02 60 Amp Yellow –ABS Pump Motor (HD Only)
F03 60 Amp Yellow –Rad Fan – If Equipped
F04 50 Amp Red 400W Inverter – If Equipped
F05 40 Amp Green –Compressor For Air Suspension – If Equipped
F06 40 Amp Green –Steering Torque Overlay Module (STOM)
F07 40 Amp Green –Starter Solenoid
F08 20 Amp Blue –NOX Sensor – If Equipped
F09 40 Amp Green –Diesel / Fuel Heater – If Equipped
F09 30 Amp Pink –Gas / Brake Vacuum Pump – If Equipped
F10 40 Amp Green –CBC #2 / Ext Lights
F11 40 Amp Green –Brake System Module (ECU and Valves)
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396SERVICING AND MAINTENANCE
F1240 Amp Green –CBC #3 / Pwr Locks
F13 40 Amp Green –Blower Motor
F14 40 Amp Green –CBC #4 / Ext Lights
F15 30 Amp Pink –Power Side Steps — If Equipped
F16 30 Amp Pink –Smart-Bar Module – If Equipped
F17 30 Amp Pink –Winch Control Module – If Equipped
F19 30 Amp Pink –Diesel SCR Feed– If Equipped
F20 30 Amp Pink –Passenger Door Module
F21 30 Amp Pink –Drive Train Control Module
F22 20 Amp Blue –Gas / ECM– If Equipped
F22 25 Amp White –Diesel PCM – If Equipped
F23 30 Amp Pink –CBC #1 / Int Light
F24 30 Amp Pink –Driver Door Module
F25 30 Amp Pink –Front Wiper
F26 — –Spare
F27 — –Spare
F28 20 Amp Blue –Trailer Tow Backup Lights – If Equipped
F29 20 Amp Blue –Trailer Tow Parking Lights – If Equipped
F30 30 Amp Pink –Trailer Tow Receptacle / Trailer Tow (Separate E-Brake) / Trailer Tow
F31 – –Spare
Cavity Cartridge Fuse Micro Fuse Description

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SERVICING AND MAINTENANCE397
F32– –Spare
F33 20 Amp Blue –Trans Control Module – If Equipped
F34 30 Amp Pink –Vehicle System Interface Module #2 – If Equipped
F35 30 Amp Pink –Sunroof – If Equipped
F36 30 Amp Pink –Electric Back Light – If Equipped
F37 30 Amp Pink –Diesel Frame / Fuel Heater #2– If Equipped
F38 30 Amp Pink –Integrated Trailer Brake Module – If Equipped
F39 – –Spare
F40 –10 Amp Red Ventilated Seats – If Equipped
F41 –10 Amp Red Active Grille Shutter / Active Air Dam – If Equipped
F42 –20 Amp Yellow Horn
F43 –15 Amp Blue Heated Steering Wheel – If Equipped
F44 –10 Amp Red Diagnostic Port
F46 –10 Amp Red Upfitters Relay Coil – If Equipped
F47 – –Spare
F48 – –Spare
F49 –10 Amp Red IP Cluster / CSG
F50 –20 Amp Yellow Air Suspension Control Module – If Equipped
F51 –10 Amp RedIgnition Node Module / Keyless Ignition Node Module, Radio Frequency
Hub Module / Electric Steering Column Lock - If Equipped
F52 –5 Amp Tan Battery Sensor
Cavity Cartridge Fuse Micro Fuse Description
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398SERVICING AND MAINTENANCE
F53–20 Amp Yellow Trailer Tow – Left Turn/Stop Lights - If Equipped
F54 –20 Amp Yellow Non Memory Adjustable Pedals - If Equipped
F55 – –Spare
F56 –10 Amp Red Fuel Vapor Blocker Valve - If Equipped
F57 –20 Amp Yellow TCM / PCM / Solenoid Trans Pressure SW (RFE Trans Only) – If Equipped
F58 –10 Amp Red Bed Lighting (LED) – If Equipped
F60 – —Spare
F61 –10 Amp Red NH3 Sensor / PM Sensor – If Equipped
F62 –10 Amp Red Air Conditioning Clutch
F63 –20 Amp Yellow Ignition Coils / CAPS
F64 –25 Amp Clear Fuel Injectors / Powertrain Control Module / SRV – If Equipped
F65 –10 Amp Red MOD Inverter (Wake Up) / Power Port / USB IP / WCPM – If Equipped
F66 –10 Amp Red Sunroof / USB Rear– If Equipped
F67 –10 Amp Red UCI Port / USB Front
F68 –10 Amp Red AEB RACAM HTR – If Equipped
F69 –15 Amp Blue SCR Module 12 Volt– If Equipped
F70 –30 Amp Green Fuel Pump Motor / K09 RLY Coil Feed – If Equipped
F71 –25 Amp Clear Amplifier / Active Noise Cancellation – If Equipped
F72 – —Spare
F73 –20 Amp Yellow Fuel Transfer Pump – If Equipped
Cavity Cartridge Fuse Micro Fuse Description

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SERVICING AND MAINTENANCE399
F74–10 Amp Red Backup Alarm – If Equipped
F75 –10 Amp Red ATMM / Coil-SCR Module RLY – If Equipped
F76 –10 Amp Red Electronic Stability Control — If Equipped
F77 –10 Amp Red Drivetrain Control Module / Front Axle Disconnect Module / TCM/ STOM
F78 –15 Amp BlueEngine Control Module / Powertrain Control Module / AEB RACM MOD /
Feed To AUX PDC Relay Coils/ HRLS
F79 –15 Amp Blue ID / Clearance Lights
F80 –10 Amp Red Overhead Console / Assist / 911 – If Equipped
F81 –20 Amp Yellow Trailer Tow Right Turn / Stop Lights - If Equipped
F82 –10 Amp Red Steering Column Control Module / Cruise Control
F83 – –Spare
F84 –15 Amp Blue ASBM / HVAC / ICS / Rear Heated Seat Switches
F85 –10 Amp Red Airbag Module
F86 –10 Amp Red Airbag Module
F87 –10 Amp RedAir Suspension / ITBM / Steering Column Control Module / MOD Gateway
CAN-C Trailer TPM
F88 –15 Amp Blue Instrument Panel Cluster
F90/F91 –20 Amp Yellow Power Outlet / Batt
Power Outlet / Acc
F92 – –Spare
F93 – –Spare
Cavity Cartridge Fuse Micro Fuse Description
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SERVICING AND MAINTENANCE401
BULB REPLACEMENT
Replacement Bulbs
NOTE:
See an authorized dealer for LED bulb replacement.
All of the inside bulbs are brass or glass-wedge base. Aluminum base bulbs are not approved.
Interior Bulbs
Bulb Name Bulb Number
Overhead Console Lamps TS 212–9
Dome Lamp 7679
NOTE:
For lighted switches, see an authorized dealer for replacement instructions.
Exterior Bulbs
Bulb Name Bulb Number
Low Beam (Halogen Reflector Headlamp) H11LL
High Beam (Halogen Reflector Headlamp) 9005LL
Low & High Beam (LED Reflector Headlamp) LED (Serviced at an authorized dealer)
Low & High Beam (LED Projector Headlamp) LED (Serviced at an authorized dealer)
Turn Signal / Front Position (Halogen Reflector Headlamp) 7444NA
Turn Signal (LED Projector Headlamp) LED (Serviced at an authorized dealer)
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406SERVICING AND MAINTENANCE
2. Rotate the bulb socket a quarter turn and
pull it from the lamp assembly.

Removing Bulb Socket From Clearance Lamp

3. Pull the bulb straight from it's socket and replace.
TIRES
TIRE SAFETY INFORMATION
Tire safety information will cover aspects of the
following information: Tire Markings, Tire
Identification Numbers, Tire Terminology and
Definitions, Tire Pressures, and Tire Loading.
Tire Markings

Tire Markings

NOTE:

P (Passenger) — Metric tire sizing is based on US
design standards. P-Metric tires have the letter “P” molded into the sidewall preceding the size
designation. Example: P215/65R15 95H.

European — Metric tire sizing is based on
European design standards. Tires designed
to this standard have the tire size molded
into the sidewall beginning with the section
width. The letter "P" is absent from this tire
size designation. Example: 215/65R15 96H.
LT (Light Truck) — Metric tire sizing is based
on US design standards. The size designation
for LT-Metric tires is the same as for P-Metric
tires except for the letters “LT” that are
molded into the sidewall preceding the size
designation. Example: LT235/85R16.
Temporary spare tires are designed for
temporary emergency use only. Temporary
high pressure compact spare tires have the
letter “T” or “S” molded into the sidewall
preceding the size designation. Example:
T145/80D18 103M.
High flotation tire sizing is based on US
design standards and it begins with the tire
diameter molded into the sidewall. Example:
31x10.5 R15 LT.

1 — US DOT Safety Standards Code (TIN)

2 — Size Designation
3 — Service Description
4 — Maximum Load
5 — Maximum Pressure
6 — Treadwear, Traction and Tempera
-
ture Grades

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SERVICING AND MAINTENANCE407
Tire Sizing Chart
EXAMPLE:
Example Size Designation: P215/65R15XL 95H, 215/65R15 96H, LT235/85R16C, T145/80D18 103M, 31x10.5 R15 LT
P = Passenger car tire size based on US design standards, or
"....blank...." = Passenger car tire based on European design standards, or
LT = Light truck tire based on US design standards, or
T or S = Temporary spare tire or
31 = Overall diameter in inches (in)
215, 235, 145 = Section width in millimeters (mm)
65, 85, 80 = Aspect ratio in percent (%)
Ratio of section height to section width of tire, or
10.5 = Section width in inches (in)
R = Construction code
"R" means radial construction, or
"D" means diagonal or bias construction
15, 16, 18 = Rim diameter in inches (in)
Service Description:
95 = Load Index
A numerical code associated with the maximum load a tire can carry
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