2021 RAM 1500 brake

414SERVICING AND MAINTENANCE
PRIMING IF THE ENGINE HAS RUN OUT
O
F FUEL — DIESEL ENGINE

1. Add a substantial amount of fuel to the
tank, approximately 2 to 5 gal (8 L to 19 L).

2. Press ignition switch twice without your foot on brake to put vehicle in ON/RUN position.
This will activate the in tank fuel pump for
approximately 30 seconds. Repeat this
process twice.
3. Start the engine using the “Normal Starting” procedure Ú page 144.
NOTE:
The engine may run rough until the air is forced
from all the fuel lines. NOTE:
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.
In addition, commercially available fuel addi
-
tives are not necessary for the proper opera -
tion of your diesel engine.
For extreme cold conditions, "Mopar
Premium Diesel Fuel Treatment" is recom -
mended to assist with cold starting.
INTERVENTION REGENERATION
S
TRATEGY — MESSAGE PROCESS FLOW
(D
IESEL ENGINE)
This engine meets all required diesel engine
emissions standards. To achieve these
emissions standards, your vehicle is equipped
with a state-of-the-art engine and exhaust
system. These systems are seamlessly
integrated into your vehicle and managed by
the 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.
Additionally, your vehicle has the ability to alert
you to additional maintenance required on your
vehicle or engine Ú page 114.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.
CAUTION!
The starter motor will engage for
approximately 30 seconds at a time. Allow
two minutes between cranking intervals.
WARNING!
Do not use alcohol or gasoline as a fuel
blending agent. They can be unstable under
certain conditions and be hazardous or
explosive when mixed with diesel fuel.
CAUTION!
Due to lack of lubricants in alcohol or
gasoline, the use of these fuels can cause
damage to the fuel system.
WARNING!
A hot exhaust system can start a fire if you
park over materials that can burn, such as
grass or leaves, and those items that come
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.

21_DT_OM_EN_USC_t.book Page 414

SERVICING AND MAINTENANCE425
(Continued)
and through another hose to the intake
manifold of the engine. This cooling process
enables more efficient burning of fuel resulting
in fewer emissions.
To guarantee optimum performance of the
system, keep the surfaces of the charge air
cooler, condenser and radiator clean and free
of debris. Periodically check the hoses leading
to and from the charge air cooler for cracks or
loose clamps resulting in loss of pressure and
reduced engine performance.
BRAKE SYSTEM
In order to ensure brake system performance,
all brake system components should be
inspected periodically Ú page 395.
Fluid Level Check — Brake Master Cylinder
The fluid level of the brake master cylinder
should be checked whenever the vehicle is
serviced, or immediately if the brake system
warning light is on. If necessary, add fluid to
bring level within the designated marks on the
side of the reservoir of the brake master
cylinder. Be sure to clean the top of the master
cylinder area before removing cap. With disc
brakes, fluid level can be expected to fall as the
brake pads wear. Brake fluid level should be
checked when pads are replaced. If the brake
fluid is abnormally low, check the system for
leaks Úpage 478.
WARNING!
Riding the brakes can lead to brake failure
and possibly a collision. Driving with your foot
resting or riding on the brake pedal can result
in abnormally high brake temperatures,
excessive lining wear, and possible brake
damage. You would not have your full braking
capacity in an emergency.
WARNING!
Use only manufacturer's recommended
brake fluid Ú page 478. Using the wrong
type of brake fluid can severely damage
your brake system and/or impair its perfor -
mance. The proper type of brake fluid for
your vehicle is also identified on the original
factory installed hydraulic master cylinder
reservoir.
To avoid contamination from foreign matter
or moisture, use only new brake fluid or
fluid that has been in a tightly closed
container. Keep the master cylinder reser -
voir cap secured at all times. Brake fluid in
a open container absorbs moisture from
the air resulting in a lower boiling point. This
may cause it to boil unexpectedly during
hard or prolonged braking, resulting in
sudden brake failure. This could result in a
collision.
Overfilling the brake fluid reservoir can
result in spilling brake fluid on hot engine
parts, causing the brake fluid to catch fire.
Brake fluid can also damage painted and
vinyl surfaces, care should be taken to
avoid its contact with these surfaces.
Do not allow petroleum based fluid to
contaminate the brake fluid. Brake seal
components could be damaged, causing
partial or complete brake failure. This could
result in a collision.
WARNING! (Continued)
8

21_DT_OM_EN_USC_t.book Page 425

430SERVICING AND MAINTENANCE
F2650 Amp Red –ESP Module
F27 30 Amp Pink –Front Wiper
F28 –10 Amp Red PCM / ECM
F29 40 Amp Green –ESP Module
F30 ––Spare
F31 ––Spare
F32 20 Amp Blue –ECM / PCM
F33 30 Amp Pink –Brake Vacuum Pump
F34 ––Spare
F35 –10 Amp RedPCM / ECM / Power Pack Unit (PPU) Motor Generator Unit (MGU)
Wake Up / EPS / Active Tuned Mass Module (ATMM) / ESP
F36 ––Spare
F37 –5 Amp Tan R / S Output to iPDC
F38 –10 Amp Red DTCM / Active CL TEMP VLV
F39 –15 Amp Red MOD ATMM
F40 40 Amp Green –Starter
F41 –10 Amp Red IRCAM Heaters
F42 20 Amp Blue –AUX SWITCH #5 — If Equipped
F43 –20 Amp Yellow MGU Coolant Pump
F44 –10 Amp Red Trailer Camera
F45 –10 Amp Red ADCM — If Equipped
CavityCartridge Fuse Micro Fuse Description

21_DT_OM_EN_USC_t.book Page 430

SERVICING AND MAINTENANCE433
F09––Spare
F10 40 Amp Green –HVAC Blower Motor
F11 –5 Amp Tan Output to Under-hood Power Distribution Center (UPDC) Run Coil
F12 –25 Amp Clear Mod Audio Amplifier / Active Noise Cancellation / SW Inverter
F13 –20 Amp Yellow Mod Seat Heater Front (Driver)
F14 –15 Amp Blue Mod Seat Heater Front (Steering Wheel)
F15 ––Spare
F16 ––Spare
F17 –20 Amp Yellow LT Spot Lamp — If Equipped
F18 30 Amp Pink –Motor Sunshade Sunroof
F19 ––Spare
F20 –20 Amp Yellow Comfort Rear Seat Module (CRSM) (Heat Rear RT)
F21 ––Spare
F22 ––Spare
F23 ––Spare
F24 –15 Amp Blue Mod RF Hub / Mod Ignition / Mod Cluster
F25 40 Amp Green –Mod Integrated Trailer Brake
F26 –15 Amp Blue Mod Cluster CCN / Mod Cyber Security
F27 –5 Amp Tan Mod Cluster CCN / Mod SGW
F28 –10 Amp Red Mod ORC
CavityCartridge Fuse Micro Fuse Description
8

21_DT_OM_EN_USC_t.book Page 433

434SERVICING AND MAINTENANCE
F29–20 Amp Yellow Mod CRSM (Heat Rear LT)
F30 30 Amp Pink –Mod DTCM / Mod Tailgate
F31 30 Amp Pink –Mod CBC 1 Interior Light
F32 –20 Amp Yellow RT Spot Lamp — If Equipped
F33 –10 Amp RedAssy Overhead Console / Switch 911 / Switch Assist / Heads Up
Display (HUD)
F34 –15 Amp Blue Frt & RR Ventilated Seat Motor
F35 –10 Amp RedMod Inverter / Mtr Sunshade Sunroof / Mtr Dual Sunroof / USB
Charge Only
F36 40 Amp Green –Mod CBC 2 Exterior Light 1
F37 ––Spare
F38 ––Spare
F39 ––Spare
F40 20 Amp Blue –Dome Pursuit Vehicle — If Equipped
F41 A&B –15 Amp BlueLumbar Support & Pass SW / Mod ICS Sw Bank / HVAC Ctrl / Sw
Bank Upper / Mod Ctrl Steering
F42 A&B –10 Amp RedMod Transfer Case Switch Module (TCSM) / SBW / Electric Park
Brake SW / Overhead Console (OHC) SW / E-Call / Bank 3 SW / Seat
LT & RT Vent / Mod Trailer A&B Tire Pressure / Mod Gateway Trailer
F43 A&B –10 Amp Red Port Diagnostics / Mod CD / Front & Rear USB
F44 –20 Amp Yellow Radio / DCSD / Telematics Box Mod / Fleet Telematics Module
(FTM)
Cavity
Cartridge Fuse Micro Fuse Description

21_DT_OM_EN_USC_t.book Page 434

SERVICING AND MAINTENANCE457
Your wheels are susceptible to deterioration
caused by salt, sodium chloride, magnesium
chloride, calcium chloride, etc., and other road
chemicals used to melt ice or control dust on
dirt roads. Use a soft cloth or sponge and mild
soap to wipe away promptly. Do not use harsh
chemicals or a stiff brush. They can damage the
wheel’s protective coating that helps keep them
from corroding and tarnishing. When cleaning extremely dirty wheels including
excessive brake dust, care must be taken in the
selection of tire and wheel cleaning chemicals
and equipment to prevent damage to the
wheels. Mopar Wheel Treatment or Mopar
Chrome Cleaner or their equivalent is
recommended or select a non-abrasive,
non-acidic cleaner for aluminum or chrome
wheels.NOTE:
If you intend parking or storing your vehicle for
an extended period after cleaning the wheels
with wheel cleaner, drive your vehicle and apply
the brakes to remove the water droplets from
the brake components. This activity will remove
the red rust on the brake rotors and prevent
vehicle vibration when braking.
Dark Vapor Chrome, Black Satin Chrome, or
Low Gloss Clear Coat Wheels
CAUTION!
Avoid products or automatic car washes that
use acidic solutions or strong alkaline
additives or harsh brushes. Many aftermarket
wheel cleaners and automatic car washes
may damage the wheel's protective finish.
Such damage is not covered by the New
Vehicle Limited Warranty. Only car wash soap,
Mopar Wheel Cleaner or equivalent is
recommended.
CAUTION!
Do not use scouring pads, steel wool, a bristle
brush, metal polishes or oven cleaner. These
products may damage the wheel's protective
finish. Such damage is not covered by the
New Vehicle Limited Warranty. Only car wash
soap, Mopar Wheel Cleaner or equivalent is
recommended.CAUTION!
If your vehicle is equipped with these
specialty wheels, DO NOT USE wheel
cleaners, abrasives, or polishing compounds.
They will permanently damage this finish and
such damage is not covered by the New
Vehicle Limited Warranty. HAND WASH ONLY
USING MILD SOAP AND WATER WITH A SOFT
CLOTH. Used on a regular basis; this is all that
is required to maintain this finish.
8

21_DT_OM_EN_USC_t.book Page 457

467
TECHNICAL SPECIFICATIONS
VEHICLE IDENTIFICATION NUMBER
The Vehicle Identification Number (VIN) is found
on the left front corner of the instrument panel,
visible through the windshield.
Vehicle Identification Number

NOTE:
It is illegal to remove or alter the VIN.
BRAKE SYSTEM
If power assist is lost for any reason (for
example, repeated brake applications with the
engine off), the brakes will still function.
However, you will experience a substantial
increase in braking effort to stop the vehicle.
If either the front or rear hydraulic system loses
normal braking capability, the remaining
system will still function with some loss of
overall braking effectiveness. This will be
evident by increased pedal travel during
application, greater pedal force required to slow
or stop, and the “Brake Warning Light” and the
“ABS Warning Light” will activate during brake
use.
WHEEL AND TIRE TORQUE SPECIFICATIONS
Proper lug nut/bolt torque is very important to
ensure that the wheel is properly mounted to
the vehicle. Any time a wheel has been removed
and reinstalled on the vehicle, the lug nuts/
bolts should be torqued using a properly
calibrated torque wrench using a six sided (hex)
deep wall socket.
TORQUE SPECIFICATIONS
**Use only authorized dealer recommended lug nuts/
bolts and clean or remove any dirt or oil before tightening.
Lug Nut/ Bolt
Torque Lug Nut/
Bolt Type **Lug
Nut/Bolt Size Lug Nut/
Bolt
Socket Size
130
Ft-Lbs
(176 N·m) Cone
M14 x
1.50 22 mm
9

21_DT_OM_EN_USC_t.book Page 467

478TECHNICAL SPECIFICATIONS
CHASSIS FLUIDS AND LUBRICANTS
Component Fluid, Lubricant, or Genuine Part
Automatic TransmissionUse only Mopar ZF 8&9 Speed ATF Automatic Transmission Fluid, or equivalent. Failure to use
the correct fluid may affect the function or performance of your transmission.
Transfer Case – 48-11 Active On-Demand 2–speed
Transfer Case (With 4WD AUTO) We recommend you use Mobil Fluid LT.
Transfer Case – 48-12 Part Time 2–Speed Transfer
Case (Without 4WD AUTO) We recommend you use Shell Spirax S2 ATF A389.
Front Axle We recommend you use Mopar GL-5 Synthetic Axle Lubricant SAE 75W-85.
Rear Axle (3.21/3.55) We recommend you use Mopar Synthetic Gear Lubricant SAE 75W-90 (MS-A0160).
Limited-Slip Rear Axles require the addition of 5 oz. (148 ml) Mopar Limited Slip Additive
(MS-10111).
Rear Axle (3.92) We recommend you use Mopar Synthetic Gear Lubricant SAE 75W-140 (MS-8985).
Limited-Slip Rear Axles require the addition of 5 oz. (148 ml) Mopar Limited Slip Additive
(MS-10111).
Max Tow Rear Axle (3.92) We recommend You Use Dana SAE 80W90 Axle Lubricant.
Brake Master Cylinder We recommend you use Mopar DOT 3 Brake Fluid, SAE J1709.

21_DT_OM_EN_USC_t.book Page 478