2021 RAM CHASSIS CAB fuel pump

STARTING AND OPERATING197
NOTE:

Your vehicle is equipped with a DEF injection
system. You may occasionally hear an audible
clicking noise. This is normal operation.

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
temperatures. For example, DEF may freeze
at temperatures 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.
Adding Diesel Exhaust Fluid (DEF)
The DEF gauge (located on the instrument
cluster) will display the level of DEF remaining in
the tank Ú
page 90.
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:
For the correct fluid type Ú
page 440.
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

1 — Diesel Exhaust Fluid (DEF) Fill Location
2 — Diesel Fuel Fill Location
4

21_DPF_OM_EN_USC_t.book Page 197

198STARTING AND OPERATING
(Continued)
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 tank
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.
At 40°F (4°C) you could see some increase
in the DEF gauge due to the tank thawing.
The gauge and level sensor are working prop-
erly and is just updating with proper thawed
DEF.
Excessive overfilling of the DEF tank can
result in a MIL lamp/fault code and inaccu -
rate level readings. Refilling With Nozzles
You can fill up at any DEF distributor.
Proceed as follows:
Insert the DEF nozzle in the filler, start
refilling and stop refilling at the first shut-off
(the shut-off indicates that the DEF tank is
full). DO NOT proceed with the refilling, to
prevent spillage of DEF.
Extract the nozzle.
Refilling With Containers
Proceed as follows:
Check the expiration date.
Read the advice for use on the label before
pouring the content of the bottle into the DEF
tank.
After the indication appears on the instru -
ment panel display Ú page 90 fill the DEF
tank with no more than 6 Gallons (22 liters).
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.

21_DPF_OM_EN_USC_t.book Page 198

310SAFETY
Enhanced Accident Response System
In the event of an impact, if the communication
network remains intact, and the power remains
intact, depending on the nature of the event,
the ORC will determine whether to have the
Enhanced Accident Response System perform
the following functions:
Cut off fuel to the engine (if equipped).
Cut off battery power to the electric motor
(if equipped).
Flash hazard lights as long as the battery has
power.
Turn on the interior lights, which remain on
as long as the battery has power or for
15 minutes from the intervention of the
Enhanced Accident Response System.
Unlock the power door locks.
Your vehicle may also be designed to perform
any of these other functions in response to the
Enhanced Accident Response System:
Turn off the Fuel Filter Heater, Turn off the
HVAC Blower Motor, Close the HVAC Circula -
tion Door
Cut off battery power to the:
Engine
Electric Motor (if equipped)
Electric power steering
Brake booster
Electric park brake
Automatic transmission gear selector
Horn
Front wiper
Headlamp washer pump
NOTE:

After an accident, remember to place the ignition
to the STOP (OFF/LOCK) position and remove the
key from the ignition switch to avoid draining the
battery. Carefully check the vehicle for fuel leaks
in the engine compartment and on the ground
near the engine compartment and fuel tank
before resetting the system and starting the
engine. If there are no fuel leaks or damage to
the vehicle electrical devices (e.g. headlights)
after an accident, reset the system by following
the procedure described below. If you have any
doubt, contact an authorized dealer.

Enhanced Accident Response System
Reset Procedure
In order to reset the Enhanced Accident
Response System functions after an event, the
ignition switch must be changed from ignition
START or ON/RUN to ignition OFF. Carefully
check the vehicle for fuel leaks in the engine
compartment and on the ground near the
engine compartment and fuel tank before
resetting the system and starting the engine.
After an accident, if the vehicle will not start
after performing the reset procedure, the
vehicle must be towed to an authorized dealer
to be inspected and to have the Enhanced
Accident Response System reset.

21_DPF_OM_EN_USC_t.book Page 310

376SERVICING AND MAINTENANCE
NOTE:
Over-compression of the seal due to over-tight -
ening of the drain will damage the seal, cause
a leak, and require the entire sensor to be
replaced.
3. Turn the ignition switch to OFF.
The sensor drain should not be over-tightened
during normal service operations to avoid
internal damage and future fuel leaks.
The drain should be closed and secured
without the use of tools.
If more than a couple ounces/milliliters of fuel
have been drained, follow the directions for
“Priming If The Engine Has Run Out Of Fuel”
Ú page 378
ENGINE MOUNTED FUEL FILTER
R
EPLACEMENT
NOTE:
Using a fuel filter that does not meet the
manufacturer's filtration and water sepa -
rating requirements can severely impact fuel
system life and reliability.
The engine mounted filter housing is
equipped with a No-Filter-No-Run (NFNR)
feature. Engine will not run if:
a. No filter is installed.
b. Inferior/Non-approved filter is used. Use of OEM filter is required to ensure
vehicle will run.

Engine Mounted Fuel Filter Assembly
1. Ensure engine is turned off.

2. Place drain pan under the fuel filter drain
hose.
3. Open the water drain valve a quarter turn counterclockwise and completely drain fuel
and water into the approved container.
4. Close the water drain valve.
5. Remove lid using a socket or strap wrench. Rotate counterclockwise for removal.
Remove used o-ring and discard it.
1 — Drain Valve
CAUTION!
Diesel fuel will damage blacktop paving
surfaces. Drain the filter into an appro-
priate container.
Do not prefill the fuel filter when installing a
new fuel filter. There is a possibility debris
could be introduced into the fuel filter
during this action. It is best to install the
filter dry and allow the in-tank lift pump to
prime the fuel system.

21_DPF_OM_EN_USC_t.book Page 376

SERVICING AND MAINTENANCE377
6. Remove the used filter cartridge from the
housing and dispose of according to your
local regulations.
7. Wipe clean the sealing surfaces of the lid and housing.
8. Install new o-ring back into ring groove on the filter housing and lubricate with clean
engine oil.
9. Remove new filter cartridge from plastic bag and install into housing.
NOTE:
Do not remove cartridge from bag until you
reach this step in order to keep cartridge clean.
10. Push down on the cartridge to ensure it is properly seated. Do not pre-fill the filter
housing with fuel.
11. Install lid onto housing and tighten to 22.5 ft lbs (30.5 N.m). Do not overtighten
the lid.
12. Prime the engine Ú page 378. Then start
the engine and confirm there are no leaks.UNDERBODY MOUNTED FUEL FILTER
R
EPLACEMENT
NOTE:
Using a fuel filter that does not meet the
manufacturer's filtration and water sepa -
rating requirements can severely impact fuel
system life and reliability.
The underbody mounted filter housing will
cause the engine not to run if:
a. No filter is installed.

Underbody Mounted Fuel Filter Assembly
1. Ensure engine is turned off.

2. Place drain pan under the fuel filter drain
hose.
3. Open the water drain valve one full turn counterclockwise and completely drain fuel
and water into the approved container.
4. Close the water drain valve.
5. Remove lid using a socket or strap wrench. Rotate counterclockwise for removal.
Remove used o-ring and discard it.
6. Remove the used filter cartridge from the housing and dispose of according to your
local regulations.
1 — Drain Valve
CAUTION!
Diesel fuel will damage blacktop paving
surfaces. Drain the filter into an appro-
priate container.
Do not prefill the fuel filter when installing a
new fuel filter. There is a possibility debris
could be introduced into the fuel filter
during this action. It is best to install the
filter dry and allow the in-tank lift pump to
prime the fuel system.
8

21_DPF_OM_EN_USC_t.book Page 377

378SERVICING AND MAINTENANCE
7. Wipe clean the sealing surfaces of the lid
and housing.
8. Install new o-ring back into ring groove on the filter housing and lubricate with clean
engine oil.
NOTE:
Water In Fuel (WIF) sensor is re-usable. Service
kit comes with new o-ring for filter canister and
WIF sensor.
PRIMING IF THE ENGINE HAS RUN OUT
O
F FUEL

1. Add a substantial amount of fuel to the
tank, approximately 2 to 5 gal (8L to 19L).
2. Three priming cycles must be completed.
Turn ignition to the RUN position and wait
approximately 30 seconds. This will activate
the in tank fuel pump. Turn the ignition
switch to the off position, and leave off for at
least 30 seconds. Repeat this procedure
three times before cranking the engine.
3. Start the engine using the “Normal Starting” procedure Ú page 119.
4. Once the engine starts, allow the engine to idle for a minimum of 30 seconds.
NOTE:
The engine may run rough until the air is forced
from all the fuel lines. NOTE:
A maximum blend of 5% biodiesel, meeting
ASTM specification D-975 may be used with
your Cummins diesel engine. (Chassis Cab
models not configured with B20 capability.)
A maximum blend of 20% biodiesel, meeting
ASTM specification D-7467 may be used with
your Cummins diesel engine. (Pickup models
and Chassis Cab models configured with B20
capability.)
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!
Do not engage the starter motor for more
than 15 seconds at a time. Allow two minutes
between the 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.

21_DPF_OM_EN_USC_t.book Page 378

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)
8

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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

21_DPF_OM_EN_USC_t.book Page 398