2003 DODGE RAM fuel filter

FUEL TANK MODULE
DESCRIPTION
An electric fuel pump isnot usedin the fuel tank
module for diesel powered engines. Fuel is supplied
by the engine mounted fuel transfer (lift) pump.
The fuel tank module is installed in the top of the
fuel tank (Fig. 23). The fuel tank module contains
the following components:
²Fuel reservoir
²A separate in-tank fuel filter
²Fuel gauge sending unit (fuel level sensor)
²Fuel supply line connection
²Fuel return line connection
²Auxiliary non-pressurized fitting
OPERATION
Refer to Fuel Gauge Sending Unit.
REMOVAL
(1) Drain and remove fuel tank. Refer to Fuel
Tank Removal/Installation.
(2) Thoroughly clean area around tank module at
top of tank.
(3) The plastic fuel tank module locknut is
threaded onto fuel tank. Install Special Tool 6856 tolocknut and remove locknut (Fig. 24). The fuel tank
module will spring up when locknut is removed.
(4) Remove module from fuel tank.
INSTALLATION
CAUTION: Whenever the fuel tank module is ser-
viced, the rubber gasket must be replaced.
(1) Thoroughly clean locknut and locknut threads
at top of tank.
(2) Using new gasket, carefully position fuel tank
module into opening in fuel tank.
(3) Position locknut over top of fuel tank module.
Install locknut finger tight.
(4) When looking down at tank from drivers side of
tank, the fuel line connectors and fuel gauge electri-
cal connector should all be pointed to drivers side of
vehicle. Rotate and align if necessary before tighten-
ing locknut.This step must be performed to pre-
vent the module's float from contacting side of
fuel tank.
(5) Tighten locknut to 24 - 44 N´m (18 - 32 ft. lbs.)
torque.
(6) Install fuel tank. Refer to Fuel Tank Removal/
Installation.
FUEL TRANSFER PUMP
DESCRIPTION
The fuel transfer pump (fuel lift pump) is attached
to the rear of the fuel filter/water separator housing.
The 12±volt electric pump is operated and controlled
by the Engine Control Module (ECM).
Fig. 23 FUEL TANK MODULE - DIESEL
1 - TOP OF FUEL TANK
2 - AUX. FITTING
3 - ELEC. CONNECTOR
4 - FUEL TANK MODULE (TOP)
5 - LOCKNUT
6 - FUEL SUPPLY LINE
7 - FUEL RETURN LINE
Fig. 24 LOCKNUT REMOVAL/INSTALLATION -
TYPICAL MODULE
1 - SPECIAL TOOL 6856
2 - LOCKNUT
DRFUEL DELIVERY - DIESEL 14 - 75

OPERATION
The purpose of the fuel transfer pump is to supply
(transfer) a low-pressure fuel source:fromthe fuel
tank,throughthe fuel filter/water separator andto
the fuel injection pump. Here, the low-pressure is
raised to a high-pressure by the fuel injection pump
for operation of the high-pressure fuel injectors.
Check valves within the pump, control direction of
fuel flow and prevent fuel bleed-back during engine
shut down.
Maximum current flow to the pump is 5 amperes.
With the engine running, the pump has a 100 per-
cent duty-cycle with a minimum pressure of 11.5 psi.
The transfer pump is self-priming: When the key is
first turned on (without cranking engine), the pump
will operate for approximately 1/2 second and then
shut off. The pump will also operate for up to 25 sec-
onds after the starter is engaged, and then disen-
gaged and the engine is not running. The pump
shuts off immediately if the key is on and the engine
stops running.
The fuel volume of the transfer pump will always
provide more fuel than the fuel injection pump
requires. Excess fuel is returned from the injection
pump through an overflow valve, and then back to
the fuel tank.
REMOVAL
The fuel transfer pump (fuel lift pump) is attached
to the rear of the fuel filter/water separator housing
(Fig. 25).
(1) Drain fuel from fuel filter housing. Refer to
Fuel Filter/Water Separator - Removal. See Draining.
(2) Disconnect electrical connector (Fig. 25) from
fuel transfer pump.
(3) Disconnect fuel tank supply line from fuel
transfer pump extension line. Do this at disconnec-
tion point at inside of left inner frame rail (Fig. 26).
Refer to quick-connect fittings for procedures.The
fuel line extension is permanently attached to
the transfer pump. Do not attempt to discon-
nect fuel line at transfer pump.
(4) Remove 4 pump mounting bolts (hex-allen),
and remove pump from fuel filter housing.
(5) Confirm that transfer pump o-ring is also
removed from fuel filter housing.
INSTALLATION
(1) Install a new o-ring to fuel transfer pump.
(2) Lubricate o-ring and OD of transfer pump inlet
connector.
(3) Position fuel transfer pump onto fuel filter
housing.Do not use mounting bolts to draw
transfer pump to filter housing.
Fig. 25 FUEL TRANSFER (LIFT) PUMP
1 - FILTER HOUSING
2 - ELEC. CONNECTOR
3 - FUEL TRANSFER (LIFT) PUMP
4 - FUEL LINE EXTENTION
5 - MOUNTING BOLTS (4)
Fig. 26 TRANSFER PUMP FUEL LINE CONNECT
1 - LEFT INNER FRAME RAIL
2 - FUEL RETURN LINE
3 - FUEL SUPPLY LINE
4 - QUICK-CONNECT FITTING
14 - 76 FUEL DELIVERY - DIESELDR
FUEL TRANSFER PUMP (Continued)

(4) Be sure pump is positioned flat to fuel filter
housing. Install mounting bolts and evenly tighten to
7 N´m (61 in. lbs.).
(5) Connect fuel line extension at fuel supply line.
(6) Connect electrical connector to pump.
(7)Prime System:Cycle key to actuate transfer
pump or use DRB II Scan Tool to actuate transfer
pump. Check for leaks.
(8) Operate engine and check for fuel leaks.
CASCADE OVERFLOW VALVE
DESCRIPTION
The cascade overflow valve is located on the top/
rear side of the fuel injection pump (Fig. 27).
OPERATION
When the fuel control actuator (FCA) is opened,
the maximum amount of fuel is being delivered to
the fuel injection pump. Any fuel that does not enter
the injection pump is directed to the cascade overflow
valve. The cascade valve regulates how much excess
fuel is used for lubrication of the injection pump, and
is also used to route excess fuel through the drain
circuit and back into the fuel tank.
REMOVAL
REMOVAL/INSTALLATION
The cascade overflow valve is not serviced sepa-
rately.
WATER IN FUEL SENSOR
DESCRIPTION
The Water-In-Fuel (WIF) sensor is located on the
side of the fuel filter/water separator canister (Fig.
28), or (Fig. 29).
Fig. 27 OVERFLOW VALVE
1 - BANJO BOLTS
2 - PUMP MOUNTING NUTS (3)
3 - FUEL INJECTION PUMP
4 - CASCADE OVERFLOW VALVE
Fig. 28 FILTER HOUSING (EARLY)
1 - FILTER HOUSING
2 - FUEL HEATER AND THERMOSTAT
3 - FUEL HEATER MOUNTING SCREWS
4 - FUEL HEATER ELEC. CONNECTOR
5 - DRAIN VALVE
6 - DRAIN VALVE MOUNTING SCREWS
7 - DRAIN HOSE
8 - WIF SENSOR
9 - WIF SENSOR ELEC. CONNECTOR
DRFUEL DELIVERY - DIESEL 14 - 77
FUEL TRANSFER PUMP (Continued)

OPERATION
The sensor sends an input to the Engine Control
Module (ECM) when it senses water in the fuel filter/
water separator. As the water level in the filter/sep-
arator increases, the resistance across the WIF
sensor decreases. This decrease in resistance is sent
as a signal to the ECM and compared to a high
water standard value. Once the value reaches 30 to
40 kilohms, the ECM will activate the water-in-fuel
warning lamp through CCD bus circuits. This all
takes place when the ignition key is initially put in
the ON position. The ECM continues to monitor the
input at the end of the intake manifold air heater
post-heat cycle.
REMOVAL
The Water-In-Fuel (WIF) sensor is located at the
side of fuel filter/water separator canister. Refer to
Fuel Filter/Water Separator Removal/Installation for
WIF sensor removal/installation procedures.
FUEL DRAIN CIRCUIT
OPERATION
The Fuel Drain Circuit incorporates several
sources of fuel return. Fuel travels from the fuel tank
to the fuel transfer pump and is forced through the
fuel filter. A portion of that fuel travels through the
fuel filter and into the fuel injection pump, while the
rest of the fuel flows through a passage in the fuel
filter housing. It then goes to a fuel drain line and
returns back to the fuel tank.
The fuel that flows to the fuel pump is pressurized
and sent into a passage in the fuel pump. At this
point the fuel is channeled into two passages. One
passage sends fuel to the FCA (Fuel Control Actua-
tor). The other passage sends fuel to the cascade
overflow valve. The overflow valve sends some fuel to
a lubrication passage. The rest of the fuel is sent to a
drain passage which connects to an external fuel
line. This fuel line is connected to the same fuel filter
housing passage that the fuel transfer pump is con-
nected to.
Fuel that travels through the FCA is pressurized
by the fuel injection pump and sent through an
external high pressure fuel line to the fuel rail. At
the fuel rail, fuel is sent to the fuel injectors. If fuel
pressure in the fuel rail becomes excessive, the pres-
sure limiting valve opens and sends fuel through an
external fuel line. This line is connected to the fuel
filter housing at the fuel pump drain.
At the fuel injector, fuel that is not injected is used
for lubrication of the fuel injectors. This fuel then
travels through an internal passage in the rear of the
cylinder head, an then into an external fuel line. This
line is connected to the vehicles fuel return line, and
returns excess fuel back to the fuel tank.
Fig. 29 FILTER HOUSING (LATE)
1 - FILTER HOUSING
2 - FUEL HEATER AND THERMOSTAT
3 - FUEL HEATER MOUNTING SCREWS
4 - FUEL HEATER ELEC. CONNECTOR
5 - WIF SENSOR
6 - WIF SENSOR ELEC. CONNECTOR
7 - DRAIN HOSE
8 - DRAIN VALVE MOUNTING SCREWS
9 - DRAIN VALVE
14 - 78 FUEL DELIVERY - DIESELDR
WATER IN FUEL SENSOR (Continued)

OPERATION
High-pressure fuel is supplied from the injection
pump, through a high-pressure fuel line, through a
fuel pressure limiting valve, into a fuel rail, through
high-pressure lines, through steel connectors and
into the solenoid actuated fuel injector. The ECM
actuates the solenoid causing the needle valve to rise
and fuel flows through the spray holes in the nozzle
tip into the combustion chamber.
Each fuel injector is connected to the fuel rail by a
high-pressure fuel line with a steel connector. This
steel connector is positioned into the cylinder head
and sealed with an o-ring. The connectors are sealed
to the high-pressure fuel lines with fittings. The fer-
rule on the end of the high-pressure fuel line pushes
against the steel connector when the fuel line fitting
is torqued into the cylinder head. This torquing force
provides a sealing pressure between both the fuel
line-to-connector and the fuel connector-to-fuel injec-
tor.The fitting torque is very critical.If the fit-
ting is under torqued, the mating surfaces will not
seal and a high-pressure fuel leak will result. If the
fitting is over torqued, the connector and injector will
deform and also cause a high-pressure fuel leak. This
leak will be inside the cylinder head and will not bevisible. The result will be a possible fuel injector
miss-fire and low power.
The fuel injectors use hole type nozzles. High-pres-
sure flows into the side of the injector, the ECM acti-
vates the solenoid causing the injector needle to lift
and fuel to be injected. The clearances in the nozzle
bore are extremely small and any sort of dirt or con-
taminants will cause the injector to stick. Because of
this, it is very important to do a thorough cleaning of
any lines before opening up any fuel system compo-
nent. Always cover or cap any open fuel connections
before a fuel system repair is performed.
Each fuel injector connector tube contains an edge
filter that breaks up small contaminants that enter
the injector. The edge filter uses the injectors pulsat-
ing high-pressure to break up most particles so they
are small enough to pass through the injector.The
edge filters are not a substitute for proper
cleaning and covering of all fuel system compo-
nents during repair.
The bottom of each fuel injector is sealed to the
cylinder head with a1.5mmthick copper shim (gas-
ket). The correct thickness shim must always be re-
installed after removing an injector.
Fuel pressure in the injector circuit decreases after
injection. The injector needle valve is immediately
Fig. 15 HIGH-PRESSURE CONNECTOR
1 - HIGH-PRESSURE CONNECTOR (TO FUEL INJECTOR)
2 - O-RING
3 - CONNECTOR RETAINER4 - FUEL RAIL
5 - HIGH-PRESSURE FUEL LINES
6 - LOCATING PINS
14 - 86 FUEL INJECTION - DIESELDR
FUEL INJECTOR (Continued)

(8) Remove 3 injector rail mounting bolts (Fig. 23).
(9) Remove rail from top of intake manifold.
INSTALLATION
(1) Clean any dirt/debris from top of intake mani-
fold and bottom of fuel rail.
(2) Position fuel rail to top of manifold and install
3 mounting bolts. Tighten 3 bolts to 24 N´m (18 ft.
lbs.) torque.
(3) Install all high-pressure lines to rail. Refer to
Fuel Lines for procedures.
(4) Reposition wiring harness to intake manifold
and install new tie wraps.
(5) Position fuel limiting valve and install banjo
bolt. Tighten bolt to 30 N´m (22 ft. lbs.) torque.
(6) Connect electrical connector to fuel pressure
sensor.
(7) Position 2 positive (+) cables to intake heater
studs. Install 2 nuts.
(8) Connect battery cables to both batteries.
(9) Start engine and check for leaks.
INLET AIR TEMPERATURE
SENSOR/PRESSURE SENSOR
DESCRIPTION
The combination, dual function Inlet Air Tempera-
ture/Pressure Sensor is located on the air cleaner (fil-
ter) cover.
OPERATION
The Inlet Air Temperature/Pressure Sensor is a
combination dual-function sensor. The sensor element
extends into the intake air stream at the top of the
air filter housing. Ambient air temperature as well as
barometric pressure is monitored by this sensor. The
Engine Control Module (ECM) monitors signals from
this sensor.
REMOVAL
The Inlet Air Temperature/Pressure Sensor is
located on the air cleaner cover (Fig. 24).
(1) Disconnect electrical connector at sensor (Fig.
25).
(2) Remove two Torx-type mounting screws.
(3) Remove sensor from air cleaner cover.
(4) Check condition of sensor o-ring (Fig. 26).
INSTALLATION
(1) Check condition of sensor o-ring.
(2) Position sensor into top of air cleaner cover
with a slight twisting action.
(3) Install 2 mounting screws.
(4) Install electrical connector.
Fig. 23 FUEL INJECTOR RAIL
1 - FUEL RAIL MOUNTING BOLTS (3)
2 - INSULATED CLAMPS
3 - FUEL INJECTOR RAIL
Fig. 24 IAT/PRESSURE SENSOR LOCATION - 5.9L
DIESEL
1 - CLIPS
2 - FILTER COVER
3 - FILTER MINDERŸ
4 - INLET AIR TEMPERATURE/ PRESSURE SENSOR
5 - FILTER HOUSING
14 - 90 FUEL INJECTION - DIESELDR
FUEL INJECTOR RAIL (Continued)

INTAKE AIR HEATER
DESCRIPTION
The intake manifold air heater element assembly
is located in the top of the intake manifold.
OPERATION
The air heater elements are used to heat incoming
air to the intake manifold. This is done to help
engine starting and improve driveability with cool or
cold outside temperatures.
Electrical supply for the 2 air heater elements is
controlled by the Engine Control Module (ECM)
through the 2 air heater relays. Refer to Intake Man-
ifold Air Heater Relays for more information.
Two heavy-duty cables connect the 2 air heater ele-
ments to the 2 air heater relays. Each of these cables
will supply approximately 95 amps at 12 volts to an
individual heating element within the heater block
assembly.
Refer to the Powertrain Diagnostic Procedures
manual for an electrical operation and complete
description of the intake heaters, including pre-heat
and post-heat cycles.
REMOVAL
If servicing either of the heater elements, the
entire block/element assembly must be replaced.
(1) Disconnect both negative battery cables at both
batteries. Cover and isolate ends of both cables.
(2) Remove both the intake manifold air intake
tube (above injection pump), and its rubber connector
hose (Fig. 27).
(3) Lift 2 rubber covers (Fig. 28) to gain access to 2
positive (+) cable nuts. Remove these 2 nuts (Fig. 29)
and remove 2 cables from studs.
(4) Disconnect ground strap (Fig. 28) at heater ele-
ment stud.
(5) Remove wiring harness clips.
(6) Remove engine oil dipstick tube bracket from
air inlet connection and fuel filter housing.
(7) Remove 4 housing mounting bolts (Fig. 28) and
remove heater element assembly.
INSTALLATION
If servicing either of the heater elements, the
entire block/element assembly must be replaced.
(1) Using 2 new gaskets, position element assem-
bly and air housing to intake manifold.
(2) Position ground cable to air housing.
(3) Install 4 housing bolts and tighten to 24 N´m
(18 ft. lbs.) torque.
(4) Connect 2 positive (+) heater cables at cable
mounting studs.Do not allow either of the cable
eyelets to contact any other metal source other
than the cable nuts/studs.
Fig. 25 INLET/PRESSURE SENSOR REMOVAL/
INSTALLATION
1 - INLET/PRESSURE SENSOR
2 - ELEC. CONNECTOR
3 - SENSOR MOUNTING SCREWS (2)
4 - TOP OF AIR FILTER COVER
Fig. 26 SENSOR O-RING
1 - IAT/PRESSURE SENSOR
2 - O-RING
DRFUEL INJECTION - DIESEL 14 - 91
INLET AIR TEMPERATURE SENSOR/PRESSURE SENSOR (Continued)

IDENTIFICATION
Transmission identification numbers are stamped
on the left side of the case just above the oil pan gas-
ket surface (Fig. 2). Refer to this information when
ordering replacement parts.
GEAR RATIOS
The 46RE gear ratios are:
1st.................................2.45:1
2nd................................1.45:1
3rd................................1.00:1
4th.................................0.69:1
Rev..................................2.21
OPERATION
The application of each driving or holding compo-
nent is controlled by the valve body based upon the
manual lever position, throttle pressure, and gover-
nor pressure. The governor pressure is a variable
pressure input to the valve body and is one of the
signals that a shift is necessary. First through fourth
gear are obtained by selectively applying and releas-
ing the different clutches and bands. Engine power is
thereby routed to the various planetary gear assem-
blies which combine with the overrunning clutch
assemblies to generate the different gear ratios. The
torque converter clutch is hydraulically applied and
is released when fluid is vented from the hydraulic
circuit by the torque converter control (TCC) solenoid
on the valve body. The torque converter clutch is con-
trolled by the Powertrain Control Module (PCM). The
torque converter clutch engages in fourth gear, and
in third gear under various conditions, such as when
the O/D switch is OFF, when the vehicle is cruising
on a level surface after the vehicle has warmed up.
The torque converter clutch can also be engaged in
the manual second gear position if high transmission
temperatures are sensed by the PCM. The torque
converter clutch will disengage momentarily when an
increase in engine load is sensed by the PCM, such
as when the vehicle begins to go uphill or the throttle
pressure is increased. The torque converter clutch
feature increases fuel economy and reduces the
transmission fluid temperature.
Since the overdrive clutch is applied in fourth gear
only and the direct clutch is applied in all ranges
except fourth gear, the transmission operation for
park, neutral, and first through third gear will be
described first. Once these powerflows are described,
the third to fourth shift sequence will be described.
1 - TORQUE CONVERTER 11 - DIRECT CLUTCH
2 - INPUT SHAFT 12 - PLANETARY GEAR
3 - OIL PUMP 13 - OUTPUT SHAFT
4 - FRONT BAND 14 - SEAL
5 - FRONT CLUTCH 15 - INTERMEDIATE SHAFT
6 - REAR CLUTCH 16 - OVERDRIVE OVERRUNNING CLUTCH
7 - PLANETARIES 17 - DIRECT CLUTCH SPRING
8 - REAR BAND 18 - OVERDRIVE PISTON RETAINER
9 - OVERRUNNING CLUTCH 19 - FILTER
10 - OVERDRIVE CLUTCH 20 - VALVE BODY
Fig. 2 Transmission Part And Serial Number
Location
1 - PART NUMBER
2 - BUILD DATE
3 - SERIAL NUMBER
DRAUTOMATIC TRANSMISSION - 46RE 21 - 133
AUTOMATIC TRANSMISSION - 46RE (Continued)