2021 RAM CHASSIS CAB water pump

196STARTING AND OPERATING
LOOSE FUEL FILLER CAP MESSAGE
If the vehicle diagnostic system
determines that the fuel filler cap
is loose, improperly installed, or
damaged, a loose gASCAP indicator
will display in the instrument cluster telltale
display area Ú page 90. 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.
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.
DIESEL EXHAUST FLUID
Your vehicle is equipped with a Selective
Catalytic 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 quantity
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
For system messages and warnings Úpage 90.
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.

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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.

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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.

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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

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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.

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