fuel tank removal DODGE RAM 2002 Service Repair Manual

SPECIAL TOOLS
SUSPENSION-REAR
BUSHINGS
REMOVAL
(1) Remove the spring from the vehicle.
(2) Position the spring eye in a press.
(3) Press the bushing out with an appropriate size
driver.
INSTALLATION
(1) Press new bushing into the spring eye with an
appropriate size driver. The bushing should be cen-
tered in the spring eye.
(2) Install the spring on the vehicle.
SHOCK
REMOVAL
(1) Raise vehicle and support axle.
(2) Remove the bolt and flag nut from the frame
crossmember bracket (Fig. 1).
(3) Remove the bolt and nut from the axle bracket.
(4) Remove the rear shock absorber from the vehi-
cle.
INSTALLATION
(1) Position the shock absorber in the brackets.
(2) Install the bolts through the brackets and the
shock. Install the flag nut on the top bolt and nut on
lower bolt.
(3) Tighten the upper and lower bolt/nuts Tighten
to 136 N.m (100 ft. lbs.)
(4) Remove the support and lower the vehicle.
SPRING
REMOVAL
(1) Raise the vehicle and support the axle to
remove all weight from the springs.
(2) Remove the nuts and spring clamp bolts that
attach the spring to the axle (Fig. 2) and (Fig. 3)and
(Fig. 4).
(3) Remove the nuts and bolts from the spring
front and rear shackle eyes.Note: To remove front
eye bolt on left side spring fuel tank must be
removed, (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY/FUEL TANK - REMOVAL).
(4) Remove the spring from the vehicle.
(5) Remove the shackle from the spring.
Puller C-3894-A
Fig. 1 Shock Absorber
1 - FLAG NUT
2 - AXLE
3 - SHOCK
BR/BEREAR 2 - 27
REAR (Continued)

VEHICLE PREPARATION FOR HEADLAMP
ALIGNMENT
(1) Verify headlamp dimmer switch and high beam
indicator operation.
(2) Verify headlamps are set for low beam opera-
tion.
(3) Correct defective components that could hinder
proper headlamp alignment.
(4) Verify proper tire inflation.
(5) Clean headlamp lenses.
(6) Verify that luggage area is not heavily loaded.
(7) Fuel tank should be FULL. Add 2.94 kg (6.5
lbs.) of weight over the fuel tank for each estimated
gallon of missing fuel.
HEADLAMP ADJUSTMENT
Headlamps can be aligned using the screen method
provided or alignment tool C-4466±A or equivalent
can be used. refer to the instructions provided with
the tool for proper procedures.
A properly aimed low beam headlamp will project
top edge of high intensity pattern on screen from 50
mm (2 in.) above to 50 mm (2 in.) below headlamp
centerline. The side-to-side outboard edge of high
intensity pattern should be from 50 mm (2 in.) left to
50 mm (2 in.) right of headlamp centerline. (Fig. 20)
The preferred headlamp alignment is 1º down
for the up/down adjustment and 0 for the left/
right adjustment.The high beam pattern should be
correct when the low beams are aligned properly.
To adjust headlamp aim, rotate alignment screws
(Fig. 21) to achieve the specified high intensity pat-
tern.
LICENSE PLATE LAMP
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove license plate lamp lens.
(3) Pull bulb from license plate lamp.
INSTALLATION
(1) Install bulb in license plate lamp.
(2) Install license plate lamp lens.
(3) Connect the battery negative cable.
LICENSE PLATE LAMP UNIT
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove screws attaching license plate panel to
cargo box.
(3) Disengage license plate lamp wire connector
from body wire harness (Fig. 22).
(4) Separate license plate lamp from vehicle.
INSTALLATION
(1) Position license plate lamp in vehicle.
Fig. 21 Aero Headlamp Alignment
1 - LEFT AND RIGHT ADJUSTMENT SCREW
2 - UP AND DOWN ADJUSTMENT SCREW
Fig. 22 License Plate Lamp Panel
1 - LIGHTING HARNESS
2 - BUMPER
3 - LICENSE PLATE LAMP
4 - SCREW
5 - LAMP PANEL
8L - 22 LAMPS/LIGHTING - EXTERIORBR/BE
HEADLAMP UNIT (Continued)

EXCESSIVE BLACK SMOKE
POSSIBLE CAUSE CORRECTION
Engine Control Module (ECM) not calibrated or ECM
has incorrect calibration.Refer to Powertrain Diagnostic Procedures Information.
Exhaust system restriction is above specifications. Check exhaust pipes for damage/restrictions. Repair as
necessary.
Fuel grade is not correct or fuel quality is poor. Temporarily change fuel brands and note condition.
Change brand if necessary.
Fuel injection pump malfunctioning. A DTC should have been set. If so, refer to Powertrain
Diagnostic Procedures Information.
Fuel injector malfunctioning. A DTC should have been set. Perform9Cylinder
Balance Test9using DRB scan tool to isolate individual
cylinders. Also refer to Powertrain Diagnostic
Procedures Information and, to (Refer to 14 - FUEL
SYSTEM/FUEL INJECTION/FUEL INJECTOR -
DIAGNOSIS AND TESTING).
Fuel return system restricted. Check fuel return line by checking overflow valve
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY -
DIAGNOSIS AND TESTING).
Intake manifold restricted. Remove restriction.
Manifold Air Pressure (Boost) Sensor or sensor circuit
malfunctioning.A DTC should have been set. Refer to Powertrain
Diagnostic Procedures Information.
Raw fuel in intake manifold. Fuel injectors leaking on engine shutdown. Do Fuel
Injector Test (Refer to 14 - FUEL SYSTEM/FUEL
INJECTION/FUEL INJECTOR - DIAGNOSIS AND
TESTING).
Static timing not correct. A DTC should have been set. If so, refer to Powertrain
Diagnostic Procedures Information. Also (Refer to 14 -
FUEL SYSTEM/FUEL DELIVERY/FUEL INJECTION
PUMP - DIAGNOSIS AND TESTING).
Turbocharger air intake restriction. Remove restriction.
Turbocharger damaged. (Refer to 11 - EXHAUST SYSTEM/TURBOCHARGER
SYSTEM/TURBOCHARGER - INSPECTION).
Turbocharger has excess build up on compressor
wheel and/or diffuser vanes.(Refer to 11 - EXHAUST SYSTEM/TURBOCHARGER
SYSTEM/TURBOCHARGER - CLEANING).
Turbocharger wheel clearance out of specification. (Refer to 11 - EXHAUST SYSTEM/TURBOCHARGER
SYSTEM/TURBOCHARGER - INSPECTION).
EXCESSIVE WHITE SMOKE
POSSIBLE CAUSE CORRECTION
Air in fuel supply: Possible leak in fuel supply side
(between transfer pump and fuel tank module).(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY/FUEL
TRANSFER PUMP - DIAGNOSIS AND TESTING).
Coolant leaking into combustion chamber. Do pressure test of cooling system (Refer to 7 -
COOLING - DIAGNOSIS AND TESTING).
Diagnostic Trouble Codes (DTC's) active or multiple,
intermittent DTC's.Refer to Powertrain Diagnostic Procedures Information.
In very cold ambient temperatures, engine block heater
is malfunctioning (if equipped).(Refer to 7 - COOLING/ENGINE/ENGINE BLOCK
HEATER - REMOVAL).
BR/BEENGINE 5.9L DIESEL 9 - 119
ENGINE 5.9L DIESEL (Continued)

(1) Disconnect the negative cable(s) from the bat-
tery.
(2) Inspect air cleaner, induction system, and
intake manifold to ensure system is dry and clear of
foreign material.
(3) Place a shop towel around the fuel injectors to
catch any fluid that may possibly be under pressure
in the cylinder head. Remove the fuel injectors (Refer
to 14 - FUEL SYSTEM/FUEL INJECTION/FUEL
INJECTOR - REMOVAL).
(4) With all injectors removed, rotate the crank-
shaft using a breaker bar and socket.
(5) Identify the fluid in the cylinders (coolant, fuel,
oil, etc.).
(6) Be sure all fluid has been removed from the
cylinders.
(7) Repair engine or components as necessary to
prevent this problem from occurring again.
(8) Squirt a small amount of engine oil into the
cylinders to lubricate the walls. This will prevent
damage on restart.
(9) Install new fuel injectors (Refer to 14 - FUEL
SYSTEM/FUEL INJECTION/FUEL INJECTOR -
INSTALLATION).
(10) Drain engine oil. Remove and discard the oil
filter (Refer to 9 - ENGINE/LUBRICATION/OIL FIL-
TER - REMOVAL).
(11) Install the drain plug. Tighten the plug to 34
N´m (25 ft. lbs.) torque.
(12) Install a new oil filter (Refer to 9 - ENGINE/
LUBRICATION/OIL FILTER - INSTALLATION).
(13) Fill engine crankcase with the specified
amount and grade of oil (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES - SPECIFICA-
TIONS).
(14) Connect the negative cable(s) to the battery.
(15) Start the engine and check for any leaks.
REMOVAL
REMOVALÐENGINE
(1) Disconnect both battery negative cables.
(2) Recover A/C refrigerant (if A/C equipped) (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING - STANDARD PROCEDURE).
(3) Raise vehicle on hoist.
(4) Drain engine coolant (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(5) Remove engine oil drain plug and drain engine
oil.
(6) Lower vehicle.
(7) Remove radiator upper hose.
(8) Remove the cooling fan shroud-to-radiator
mounting bolts.(9) Remove viscous fan/drive assembly (Refer to 7 -
COOLING/ENGINE/RADIATOR FAN - REMOVAL).
Remove the cooling fan and shroud together.
(10) Disconnect the coolant recovery bottle hose
from the radiator filler neck and remove bottle from
fan shroud (Fig. 2).
(11) Disconnect heater core supply and return
hoses from the cylinder head fitting and coolant pipe.
(12) Raise vehicle on hoist.
(13) Remove transmission and transfer case (if
equipped.).
(14) Disconnect exhaust pipe from turbocharger
extension pipe (Fig. 3).
(15) Remove starter motor (Refer to 8 - ELECTRI-
CAL/STARTING/STARTER MOTOR - REMOVAL).
(16) Disconnect A/C suction/discharge hose from
the rear of the A/C compressor.
(17) Lower vehicle.
(18) Disconnect lower radiator hose from radiator
outlet.
(19)Automatic Transmission models:Discon-
nect transmission oil cooler lines from radiator using
special tool #6931.
(20) Remove radiator (Refer to 7 - COOLING/EN-
GINE/RADIATOR - REMOVAL).
(21) Remove upper radiator support panel.
Fig. 2 Coolant Recovery Bottle
1 - T-SLOTS
2 - ALIGNMENT PIN
3 - FAN SHROUD
4 - COOLANT RESERVE/OVERFLOW TANK
BR/BEENGINE 5.9L DIESEL 9 - 123
ENGINE 5.9L DIESEL (Continued)

FUEL SYSTEM
TABLE OF CONTENTS
page page
FUEL DELIVERY - GASOLINE...............1
FUEL INJECTION - GASOLINE..............28FUEL DELIVERY - DIESEL.................54
FUEL INJECTION - DIESEL................91
FUEL DELIVERY - GASOLINE
TABLE OF CONTENTS
page page
FUEL DELIVERY - GASOLINE
DESCRIPTION - FUEL DELIVERY SYSTEM....2
OPERATION - FUEL DELIVERY SYSTEM......2
DIAGNOSIS AND TESTING - FUEL
PRESSURE LEAK DOWN TEST...........2
STANDARD PROCEDURE - FUEL SYSTEM
PRESSURE RELEASE...................3
SPECIFICATIONS
SPECIFICATIONS - FUEL SYSTEM
PRESSURE - GAS ENGINES..............3
SPECIFICATIONS - TORQUE - FUEL
DELIVERY............................4
SPECIAL TOOLS
FUEL SYSTEM........................4
FUEL FILTER/PRESSURE REGULATOR
DESCRIPTION..........................5
OPERATION............................5
REMOVAL.............................5
INSTALLATION..........................7
FUEL LEVEL SENDING UNIT / SENSOR
DESCRIPTION..........................7
OPERATION............................7
DIAGNOSIS AND TESTING - FUEL GAUGE
SENDING UNIT........................7
REMOVAL.............................7
INSTALLATION..........................8
FUEL LINES
DESCRIPTION..........................8
FUEL PUMP
DESCRIPTION..........................9
OPERATION............................9
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - FUEL PUMP
CAPACITY TEST.......................9
DIAGNOSIS AND TESTING - FUEL PUMP
PRESSURE TEST......................9DIAGNOSIS AND TESTING - FUEL PUMP
AMPERAGE TEST.....................10
FUEL PUMP MODULE
DESCRIPTION.........................12
OPERATION...........................13
REMOVAL.............................13
INSTALLATION.........................13
FUEL RAIL
DESCRIPTION
DESCRIPTION - 5.9L...................14
DESCRIPTION - 8.0L...................14
OPERATION
OPERATION - 5.9L....................14
OPERATION - 8.0L....................15
REMOVAL
REMOVAL - 5.9L......................15
REMOVAL - 8.0L......................16
INSTALLATION
INSTALLATION - 5.9L..................17
INSTALLATION - 8.0L..................18
FUEL TANK
DESCRIPTION.........................18
OPERATION...........................18
REMOVAL.............................18
INSTALLATION.........................20
FUEL TANK CHECK VALVE
DESCRIPTION.........................21
REMOVAL.............................22
INSTALLATION.........................23
INLET FILTER
REMOVAL.............................23
INSTALLATION.........................23
QUICK CONNECT FITTING
DESCRIPTION.........................24
STANDARD PROCEDURE - QUICK-CONNECT
FITTINGS...........................24
BR/BEFUEL SYSTEM 14 - 1

FUEL DELIVERY - GASOLINE
DESCRIPTION - FUEL DELIVERY SYSTEM
The fuel delivery system consists of:
²the fuel pump module containing the electric
fuel pump, fuel filter/fuel pressure regulator, rollover
valve (certain modules), fuel gauge sending unit (fuel
level sensor) and a separate fuel filter located at bot-
tom of pump module
²fuel tubes/lines/hoses
²quick-connect fittings
²fuel injector rail
²fuel injectors
²fuel tank
²fuel tank filler/vent tube assembly
²fuel tank filler tube cap
²accelerator pedal
²throttle cable
OPERATION - FUEL DELIVERY SYSTEM
Fuel is returned through the fuel pump module
and back into the fuel tank through the fuel filter/
fuel pressure regulator. A separate fuel return line
from the engine to the tank is not used with any gas-
oline powered engine.
The fuel tank assembly consists of: the fuel tank,
fuel pump module assembly, fuel pump module lock-
nut/gasket and fuel tank check valve(s) (refer to 25,
Emission Control System for Fuel Tank Check Valve
information).
A fuel filler/vent tube assembly using a pressure/
vacuum, 1/4 turn fuel filler cap is used. The fuel
filler tube contains a flap door located below the fuel
fill cap.
Also to be considered part of the fuel system is the
evaporation control system. This is designed to
reduce the emission of fuel vapors into the atmo-
sphere. The description and function of the Evapora-
tive Control System is found in 25, Emission Control
Systems.
Both fuel filters (at bottom of fuel pump module
and within fuel pressure regulator) are designed for
extended service. They do not require normal sched-
uled maintenance. Filters should only be replaced if
a diagnostic procedure indicates to do so.
DIAGNOSIS AND TESTING - FUEL PRESSURE
LEAK DOWN TEST
Use this test in conjunction with the Fuel Pump
Pressure Test and Fuel Pump Capacity Test.
Check Valve Operation:The electric fuel pump
outlet contains a one-way check valve to prevent fuel
flow back into the tank and to maintain fuel supply
line pressure (engine warm) when pump is not oper-
ational. It is also used to keep the fuel supply linefull of gasoline when pump is not operational. After
the vehicle has cooled down, fuel pressure may drop
to 0 psi (cold fluid contracts), but liquid gasoline will
remain in fuel supply line between the check valve
and fuel injectors.Fuel pressure that has
dropped to 0 psi on a cooled down vehicle
(engine off) is a normal condition.When the elec-
tric fuel pump is activated, fuel pressure should
immediately(1±2 seconds) rise to specification.
Abnormally long periods of cranking to restart a
hotengine that has been shut down for a short
period of time may be caused by:
²Fuel pressure bleeding past a fuel injector(s).
²Fuel pressure bleeding past the check valve in
the fuel pump module.
(1) Disconnect the fuel inlet line at fuel rail. Refer
to Fuel Tubes/Lines/Hoses and Clamps for proce-
dures. On some engines, air cleaner housing removal
may be necessary before fuel line disconnection.
(2) Obtain correct Fuel Line Pressure Test Adapter
Tool Hose. Tool number 6539 is used for 5/16º fuel
lines and tool number 6631 is used for 3/8º fuel lines.
(3) Connect correct Fuel Line Pressure Test
Adapter Tool Hose between disconnected fuel line
and fuel rail (Fig. 1).
Fig. 1 CONNECTING ADAPTER TOOLÐTYPICAL
1 - VEHICLE FUEL LINE
2 - TEST PORT ªTº
3 - SPECIAL TOOL 6923, 6631, 6541 OR 6539
4 - FUEL PRESSURE TEST GAUGE
5 - FUEL LINE CONNECTION AT RAIL
6 - FUEL RAIL
14 - 2 FUEL DELIVERY - GASOLINEBR/BE

SPECIFICATIONS - TORQUE - FUEL DELIVERY
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Fuel Pump Module Locknut 24-44 18-32
Fuel Rail Mounting BoltsÐ5.9L Engines 23 200
Fuel Rail Mounting BoltsÐ8.0L Engine 15 136
Fuel Tank Mounting Nuts 41 30
Fuel Hose Clamps 1 15
SPECIAL TOOLS
FUEL SYSTEM
Spanner WrenchÐ6856
Fitting, Air MeteringÐ6714
Adapters, Fuel Pressure TestÐ6539 and/or 6631
O2S (Oxygen Sensor) Remover/InstallerÐC-4907
Test Kit, Fuel PressureÐ5069
Test Kit, Fuel PressureÐC-4799-B
Fuel Line Removal ToolÐ6782
14 - 4 FUEL DELIVERY - GASOLINEBR/BE
FUEL DELIVERY - GASOLINE (Continued)

FUEL FILTER/PRESSURE
REGULATOR
DESCRIPTION
A combination fuel filter and fuel pressure regula-
tor (Fig. 2) is used on all engines. It is located on the
top of the fuel pump module. A separate frame
mounted fuel filter is not used with any engine.
Both fuel filters (at bottom of fuel pump module
and within fuel pressure regulator) are designed for
extended service. They do not require normal sched-
uled maintenance. Filters should only be replaced if
a diagnostic procedure indicates to do so.
OPERATION
Fuel Pressure Regulator Operation:The pres-
sure regulator is a mechanical device that is not con-
trolled by engine vacuum or the powertrain control
module (PCM).
The regulator is calibrated to maintain fuel system
operating pressure of approximately 339 kPa   34
kPa (49.2 psi   5 psi) at the fuel injectors. It contains
a diaphragm, calibrated springs and a fuel return
valve. The internal fuel filter (Fig. 2) is also part of
the assembly.
Fuel is supplied to the filter/regulator by the elec-
tric fuel pump through an opening tube at the bot-
tom of filter/regulator (Fig. 2) .
The regulator acts as a check valve to maintain
some fuel pressure when the engine is not operating.
This will help to start the engine. A second checkvalve is located at the outlet end of the electric fuel
pump.Refer to Fuel PumpÐDescription and
Operation for more information. Also refer to
the Fuel Pressure Leak Down Test and the Fuel
Pump Pressure Tests.
If fuel pressure at the pressure regulator exceeds
approximately 49.2 psi, an internal diaphragm opens
and excess fuel pressure is routed back into the tank
through the bottom of pressure regulator.
Both fuel filters (at bottom of fuel pump module
and within fuel pressure regulator) are designed for
extended service. They do not require normal sched-
uled maintenance. Filters should only be replaced if
a diagnostic procedure indicates to do so.
REMOVAL
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE, EVEN WITH ENGINE OFF.
BEFORE SERVICING FUEL FILTER/FUEL PRES-
SURE REGULATOR, FUEL SYSTEM PRESSURE
MUST BE RELEASED.
Refer to Fuel System Pressure Release in Fuel
Delivery System section of this group.
The fuel filter/fuel pressure regulator (Fig. 3) is
located at top of fuel pump module (Fig. 4) or (Fig.
5).
Fuel pump module removal is not necessary.
(1) Drain fuel tank and remove tank. Refer to Fuel
Tank Removal/Installation.
Fig. 2 Side ViewÐFilter/Regulator
1 - INTERNAL FUEL FILTER
2 - FUEL FLOW TO FUEL INJECTORS
3 - FUEL FILTER/FUEL PRESSURE REGULATOR
4 - EXCESS FUEL BACK TO TANK
5 - FUEL INLET
6 - RUBBER GROMMET
7 - TOP OF PUMP MODULE
Fig. 3 Fuel Filter/Fuel Pressure Regulator
1 - INTERNAL FUEL FILTER
2 - FUEL FLOW TO FUEL INJECTORS
3 - FUEL FILTER/FUEL PRESSURE REGULATOR
4 - EXCESS FUEL BACK TO TANK
5 - FUEL INLET
6 - RUBBER GROMMET
7 - TOP OF PUMP MODULE
BR/BEFUEL DELIVERY - GASOLINE 14 - 5

(2) The fuel filter/regulator is pressed into a rub-
ber grommet. Remove by twisting and pulling
straight up (Fig. 6).
CAUTION: Do not pull filter/regulator more than
three inches from fuel pump module. Damage to
coiled fuel tube (line) may result.
(3) Gently cut old fuel tube (line) clamp (Fig. 7)
taking care not to damage plastic fuel tube. Remove
and discard old fuel tube clamp.
(4) Remove plastic fuel tube from filter/regulator
by gently pulling downward. Remove filter/regulator
from fuel pump module.
Fig. 4 Filter/Regulator LocationÐWith 26 or 34
Gallon Fuel Tank
1 - FUEL FILTER/PRESSURE REGULATOR
2 - FUEL SUPPLY FITTING
3 - REAR FUEL TANK CHECK VALVE
4 - ELECTRICAL CONNECTOR
5 - FUEL PUMP MODULE
6 - FRONT FUEL TANK CHECK VALVE
7 - LOCKNUT
Fig. 5 Filter/Regulator LocationÐWith 35 Gallon
Fuel Tank
1 - FUEL FILTER/PRESSURE REGULATOR
2 - FUEL SUPPLY FITTING
3 - ELECTRICAL CONNECTOR
4 - LOCKNUT
5 - FUEL PUMP MODULE
6 - AUXILIARY CAPPED FITTING
Fig. 6 Filter/Regulator Removal and InstallationÐ
TYPICAL
1 - RUBBER GROMMET
2 - FUEL FILTER/FUEL PRESSURE REGULATOR
Fig. 7 Fuel Tube and ClampÐTYPICAL
1 - FUEL FILTER/FUEL PRESSURE REGULATOR
2 - TUBE CLAMP
3 - FUEL TUBE
14 - 6 FUEL DELIVERY - GASOLINEBR/BE
FUEL FILTER/PRESSURE REGULATOR (Continued)

INSTALLATION
(1) Install a new clamp over plastic fuel tube.
(2) Install filter/regulator to fuel tube. Rotate fil-
ter/regulator in fuel tube (line) (Fig. 8) until it is
pointed to drivers side of vehicle (Fig. 4) or (Fig. 5).
(3) Tighten line clamp to fuel line using special
Hose Clamp Pliers number C-4124 or equivalent
(Fig. 8) .Do not use conventional side cutters to
tighten this type of clamp.
(4) Press filter/regulator (by hand) into rubber
grommet. The assembly should be pointed towards
drivers side of vehicle (Fig. 4) or (Fig. 5) .
(5) Install fuel tank. Refer to Fuel Tank Removal/
Installation.
(6) Check for fuel leaks.
FUEL LEVEL SENDING UNIT /
SENSOR
DESCRIPTION
The fuel gauge sending unit (fuel level sensor) is
attached to the side of the fuel pump module. The
sending unit consists of a float, an arm, and a vari-
able resistor track (card).
OPERATION
The fuel pump module has 4 different circuits
(wires). Two of these circuits are used for the fuel
gauge sending unit for fuel gauge operation, and for
certain OBD II emission requirements. The other 2
wires are used for electric fuel pump operation.
For Fuel Gauge Operation:A constant current
source of about 32 mA is supplied to the resistortrack on the fuel gauge sending unit. This is fed
directly from the Powertrain Control Module (PCM).
The resistor track is used to vary the voltage depend-
ing on fuel tank float level. As fuel level increases,
the float and arm move up, which decreases voltage.
As fuel level decreases, the float and arm move
down, which increases voltage. The varied voltage
signal is returned back to the PCM through the sen-
sor return circuit. Output voltages will vary from
about .6 volts at FULL, to about 8.6 volts at EMPTY
(Jeep models), or, about 7.0 volts at EMPTY (Dodge
Truck models).NOTE: For diagnostic purposes,
this voltage can only be verified with the fuel
gauge sending unit circuit closed (i.e. having all
of the sending units electrical connectors con-
nected).
Both of the electrical circuits between the fuel
gauge sending unit and the PCM are hard-wired (not
multi-plexed). After the voltage signal is sent from
the resistor track, and back to the PCM, the PCM
will interpret the resistance (voltage) data and send
a message across the multi-plex bus circuits to the
instrument panel cluster. Here it is translated into
the appropriate fuel gauge level reading. Refer to
Instrument Panel for additional information.
For OBD II Emission Monitor Requirements:
The PCM will monitor the voltage output sent from
the resistor track on the sending unit to indicate fuel
level. The purpose of this feature is to prevent the
OBD II system from recording/setting false misfire
and fuel system monitor diagnostic trouble codes.
The feature is activated if the fuel level in the tank
is less than approximately 15 percent of its rated
capacity. If equipped with a Leak Detection Pump
(EVAP system monitor), this feature will also be acti-
vated if the fuel level in the tank is more than
approximately 85 percent of its rated capacity.
DIAGNOSIS AND TESTING - FUEL GAUGE
SENDING UNIT
The fuel gauge sending unit contains a variable
resistor (track). As the float moves up or down, elec-
trical resistance will change. Refer to Instrument
Panel and Gauges under Electrical for Fuel Gauge
testing. To test the gauge sending unit only, it must
be removed from vehicle. The unit is part of the fuel
pump module. Refer to Fuel Pump Module Removal/
Installation for procedures. Measure the resistance
across the sending unit terminals. With float in up
position, resistance should be 20 ohms  6 ohms. With
float in down position, resistance should be 220 ohms
 6 ohms.
REMOVAL
The fuel gauge sending unit (fuel level sensor) and
float assembly is located on the side of fuel pump
Fig. 8 Tightening Fuel Tube ClampÐTYPICAL
1 - TOOL C-4124
2 - TUBE CLAMP
3 - FUEL TUBE
BR/BEFUEL DELIVERY - GASOLINE 14 - 7
FUEL FILTER/PRESSURE REGULATOR (Continued)