2001 DODGE RAM sensor

Voltage to operate the fuel heater element is sup-
plied from the ignition switch, through the fuel
heater relay (also refer to Fuel Heater Relay), to the
fuel temperature sensor and on to the fuel heater ele-
ment.
The heater element operates on 12 volts, 300 watts
at 0 degrees F. As temperature increases, power
requirements decrease.
A minimum of 7 volts is required to operate the
fuel heater. The resistance value of the heater ele-
ment is less than 1 ohm (cold) and up to 1000 ohms
warm.
TESTING
(1) Disconnect electrical connector at sensor (Fig.
10).
Turn key to ON position. 12 volts should be
present at red wire. If not, check fuel heater relay
and related wiring. Refer to Relay TestÐFuel Heater.
If OK, proceed.
Turn key OFF. Check black wire in connector for
ground continuity with an ohmmeter. If continuity is
not present, correct open ground circuit. This test can
also be performed with a voltmeter by backprobing
black wire with it connected to sensor. Reconnect
electrical connector and turn key ON. Voltage drop
should not exceed 2 volts (2 volts lower than checked
at 12V+ connector). If voltage is lower, check for dirtyor corroded ground connection and repair. If OK, pro-
ceed.
(2) With electrical connector disconnected at sen-
sor and key OFF, check electrical/mechanical opera-
tion of fuel temperature sensor. Proceed to next step:
(3) Using an ohmmeter, check for continuity across
two terminals in electrical connector at side of sen-
sor. Sensor circuit should be open if fuel temperature
has risen above 75 degrees68 degrees F. Sensor cir-
cuit should be closed if fuel temperature has dropped
below 45 degrees68 degrees F. If not, replace fuel
heater assembly. This same test can also be per-
formed using a voltmeter, with key ON, and by back-
probing connector.
REMOVAL/INSTALLATION
The fuel heater/element/sensor assembly is located
inside of the fuel filter housing. Refer to Fuel Filter/
Water Separator Removal/Installation for procedures.
FUEL HEATER RELAY
DESCRIPTION
The fuel heater relay is located in Power Distribu-
tion Center (PDC) (Fig. 11). Refer to label on inside
of PDC cover for relay location.
OPERATION
Battery voltage to operate the fuel heater element
is supplied from the ignition switch through the fuel
heater relay.The fuel heater element and fuel
heater relay are not computer controlled.
Fig. 10 Fuel Heater Location
1 - FUEL HEATER AND TEMP. SENSOR
2 - FUEL FILTER/WATER SEPARATOR
3 - FUEL HEATER ELECTRICAL CONNECTOR
Fig. 11 Power Distribution Center Location
1 - CLIP
2 - BATTERY
3 - TRAY
4 - NEGATIVE CABLE
5 - POSITIVE CABLE
6 - CLIP
7 - FENDER INNER SHIELD
8 - POWER DISTRIBUTION CENTER
BR/BEFUEL DELIVERY - DIESEL 14 - 63
FUEL HEATER (Continued)

DESCRIPTIONÐFUEL PUMP 235 H.P.
The fuel injection pump is mounted to the rear of
the timing gear housing on the left side of engine
(Fig. 15).
OPERATION
The Bosch VP44 fuel injection pump (Fig. 16) is a
solenoid-valve controlled-radial-piston-distributor
type pump.
The injection pump is driven by the engine cam-
shaft. A gear on the end of the pump shaft meshes
with the camshaft gear. The pump is timed to the
engine. The VP44 is controlled by an integral (and
non-serviceable) Fuel Pump Control Module (FPCM)
(Fig. 15). The FPCM can operate the engine as an
engine controller if a Crankshaft Position Sensor
(CKP) signal is not present.
Fuel from the transfer (lift) pump enters the VP44
where it is pressurized and then distributed through
high-pressure lines to the fuel injectors. The VP44 is
cooled by the fuel that flows through it. A greater
quantity of fuel is required for cooling the VP44 than
what is necessary for engine operation. Because of
this, approximately 70 percent of fuel entering the
pump is returned to the fuel tank through the over-
flow valve and fuel return line. Refer to Overflow
Valve Description/Operation for additional informa-
tion.The VP44 is not self-priming. At least two fuel
injectors must be bled to remove air from the system.
When servicing the fuel system, disconnecting compo-
nents up to the pump will usually not require air
bleeding from the fuel system. However, removal of
the high-pressure lines, removal of the VP44 pump,
or allowing the vehicle to completely run out of fuel,
will require bleeding air from the high-pressure lines
at the fuel injectors.
VP44 timing is matched to engine timing by an off-
set keyway that fits into the pump shaft. This key-
way has a stamped number on it that is matched to
a number on the VP44 pump (each keyway is cali-
brated to each pump).
When removing/installing the VP44, the same
numbered keyway must always be installed.
Also, the arrow on the top of the keyway should
be installed pointed rearward towards the
pump.
Because of electrical control, the injection pump
high and low idle speeds are not adjustable. Also,
adjustment of fuel pump timing is not required and
is not necessary.
DIAGNOSIS AND TESTINGÐFUEL INJECTION
PUMP TIMING
With the Bosch VP44 injection pump, there are no
mechanical adjustments needed for fuel injection tim-
ing. All timing and fuel adjustments are made by the
Engine Control Module (ECM). However, if a Diag-
nostic Trouble Code (DTC) has been stored indicating
an ªengine sync errorº or a ªstatic timing errorº, per-
form the following.
Fig. 15 Fuel Injection Pump Location
1 - FPCM ELECTRICAL CONNECTOR
2 - HIGH-PRESSURE FUEL LINES
3 - FITTINGS
4 - FUEL INJECTION PUMP
5 - FPCM
Fig. 16 Bosch VP44 Fuel Injection Pump
1 - BOSCH VP44 PUMP
14 - 66 FUEL DELIVERY - DIESELBR/BE
FUEL INJECTION PUMP (Continued)

(1) Remove hose clamp and crankcase vent hose at
crankcase breather (Fig. 17). Remove crankcase
breather from gear cover. Breather threads into
cover.
(2) Remove injection pump nut and washer (Fig.
18). Locate keyway behind washer.
(3) Be sure keyway aligning fuel injection pump
shaft to injection pump gear is in proper position and
pump gear has not slipped on pump shaft.
The following steps will require removing timing
gear cover to gain access to timing gears. Refer to
Group 9, Engines for procedures.
(4) Use a T-type puller to separate injection pump
gear from pump shaft.
(5) Be sure keyway has been installed with arrow
pointed torearof pump (Fig. 19).
(6)Pump timing has been calibrated to pump
keyway. Be sure 3±digit number on pump key-
way (Fig. 19) matches 3±digit number on fuel
injection pump data plate. Plate is located on
side of injection pump (Fig. 20). Twenty±one dif-
ferent calibrated keyways/pumps are available.
(7) Verify timing marks on crank, cam and pump
are aligned (Fig. 21).
(8) Perform necessary gear alignment/repairs as
needed.
(9) Install crankcase breather to gear cover. Install
hose clamp and crankcase vent hose to breather (Fig.
17).
(10) After repairs are completed, erase DTC using
DRB Scan Tool.
REMOVAL
CAUTION: Refer to Cleaning Fuel System Parts.
(1) Disconnect both negative battery cables at both
batteries. Cover and isolate ends of cables.
(2) Thoroughly clean fuel lines at cylinder head
and injection pump ends. Thoroughly clean fuel injec-
tion pump and supply/return lines at side of pump.
(3) Disconnect 9±way electrical connector at Fuel
Pump Control Module (FPCM) (Fig. 22).
(4) Remove fuel return line at side of injection
pump by removing overflow valve (Fig. 23). Place rag
beneath overflow valve to catch excess fuel.
(5) Remove fuel supply line at side of injection
pump by removing banjo bolt (Fig. 23). Also remove
same line at top of fuel filter housing (banjo bolt).
(6) Remove all high-pressure fuel lines, intake air
tube, accelerator pedal position sensor, air intake
housing, engine oil dipstick tube, wiring clips, electri-
cal cables at intake heaters and engine lifting
bracket. Refer to High-Pressure Fuel Line Removal/
Installation. All of these items are covered in this
procedure.
(7) Remove hose clamp at crankcase vent hose
(Fig. 24) and remove hose from canister.
(8) Remove (unscrew) canister (Fig. 24) from gear
cover.
Fig. 21 Checking Fuel Injection Pump Gear Timing
1 - PUMP SHAFT
2 - KEYWAY
3 - PUMP GEAR
4 - CAM GEAR
5 - CRANKSHAFT GEAR
Fig. 22 FPCM 9±Way Connector
1 - FPCM ELECTRICAL CONNECTOR
2 - HIGH-PRESSURE FUEL LINES
3 - FITTINGS
4 - FUEL INJECTION PUMP
5 - FPCM
14 - 68 FUEL DELIVERY - DIESELBR/BE
FUEL INJECTION PUMP (Continued)

(5) Clean pump gear and pump shaft at machined
tapers (Fig. 34) with an evaporative type cleaner
such as brake cleaner.
Keyway Installation:
(6) The pump/gear keyway has an arrow and a
3±digit number stamped at top edge (Fig. 33). Posi-
tion keyway into pump shaft witharrow pointed to
rear of pump.Also be sure 3±digit number stamped
to top of keyway is same as 3±digit number stamped
to injection pump data plate (Fig. 35). If wrong key-
way is installed, a diagnostic trouble code may be
set.
(7) Position pump assembly to mounting flange on
gear cover while aligning injection pump shaft
through back of injection pump gear. When installing
pump, dowel (Fig. 34) on mounting flange must align
to hole in front of pump.
(8) After pump is positioned flat to mounting
flange, install four pump mounting nuts and tighten
finger tight only. Do not attempt a final tightening at
this time.Do not attempt to tighten (pull) pump
to gear cover using mounting nuts. Damage to
pump or gear cover may occur. The pump must
be positioned flat to its mounting flange before
attempting to tighten mounting nuts.
(9) To prevent damage or cracking of components,
tighten nuts/bolts in the following sequence:
(a) Install injection pump shaft washer and nut
to pump shaft. Tighten nutfinger tight only.
(b) Install 2 rear/lower pump mounting bolts
finger tight only.(c) Do preliminary tightening of injection pump
shaft nut to 30 N´m (15±22 ft. lbs.) torque.This is
not the final torque.
(d) Tighten 4 pump mounting nuts to 43 N´m
(32 ft. lbs.) torque.
(e) Tighten 2 rear/lower pump bracket-to-pump
bolts 24 N´m (18 ft. lbs.) torque.
(f) Do final tightening of injection pump shaft
nut to 170 N´m (125 ft. lbs.) torque. Use barring
tool to prevent engine from rotating when tighten-
ing gear.
(10) Install canister (Fig. 24) to gear cover.
(11) Install crankcase vent hose (Fig. 24) to canis-
ter and install hose clamp.
(12) Using new gaskets, install fuel return line
and overflow valve to side of injection pump (Fig. 23).
Tighten overflow valve to 24 N´m (18 ft. lbs.) torque.
(13)
Using new gaskets, install fuel supply line to
side of injection pump and top of fuel filter housing (Fig.
23). Tighten banjo bolts to 24 N´m (18 ft. lbs.) torque.
(14)Install all high-pressure fuel lines, intake air
tube, accelerator pedal position sensor, air intake hous-
ing, engine oil dipstick tube, wiring clips, electrical
cables at intake heaters and engine lifting bracket.
Refer to High-Pressure Fuel Line Removal/Installation.
All of these items are covered in this procedure.
Fig. 34 Injection Pump Installation
1 - DOWEL
2 - PUMP
3 - PUMP SHAFT TAPER
4 - INJECTION PUMP GEAR TAPER
Fig. 35 Injection Pump Data Plate Location
1 - PUMP DATA PLATE
14 - 72 FUEL DELIVERY - DIESELBR/BE
FUEL INJECTION PUMP (Continued)

(15) Connect 9±way electrical connector to Fuel
Pump Control Module (FPCM) (Fig. 22).
(16) Connect both negative battery cables to both
batteries.
(17) Bleed air from fuel system.(Refer to 14 -
FUEL SYSTEM/FUEL DELIVERY - STANDARD
PROCEDURE).
(18) Check system for fuel or engine oil leaks.
FUEL INJECTION PUMP DATA
PLATE
SPECIFICATIONS
FUEL INJECTION PUMP DATA PLATE
Pertinent information about the fuel injection
pump is machined into a boss on the drivers side of
the fuel injection pump (Fig. 36).
FUEL LEVEL SENDING UNIT /
SENSOR
DESCRIPTION
The fuel gauge sending unit (fuel level sensor) is
attached to the side of the fuel tank module. The
sending unit consists of a float, an arm, and a vari-
able resistor track (card).
OPERATION
The fuel tank module on diesel powered models
has 3 different circuits (wires). Two of these circuits
are used at the fuel gauge sending unit for fuel
gauge operation. The other wire is used for a ground.
The diesel engine does not have a fuel tank module
mounted electric fuel pump. The electric fuel pump
(fuel transfer pump) is mounted to the engine.
For Fuel Gauge Operation:A constant input
voltage source of about 12 volts (battery voltage) is
supplied to the resistor track on the fuel gauge send-
ing unit. This is fed directly from the Powertrain
Control Module (PCM).NOTE: For diagnostic pur-
poses, this 12V power source can only be veri-
fied with the circuit opened (fuel tank module
electrical connector unplugged). With the con-
nectors plugged, output voltages will vary from
about .6 volts at FULL, to about 7.0 volts at
EMPTY.The resistor track is used to vary the volt-
age (resistance) depending 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 sensor return circuit.
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.
FUEL LINES
DESCRIPTION
All fuel lines up to the fuel injection pump are con-
sidered low-pressure. This includes the fuel lines
from: the fuel tank to the fuel transfer pump, and
the fuel transfer pump to the fuel injection pump.
The fuel return lines, the fuel drain manifold and the
fuel drain manifold lines are also considered low-
pressure lines. High-pressure lines are used between
Fig. 36 Fuel Injection Pump Data Plate Location
1 - PUMP DATA PLATE
BR/BEFUEL DELIVERY - DIESEL 14 - 73
FUEL INJECTION PUMP (Continued)

CAUTION: The high-pressure fuel lines must be
clamped securely in place in the holders. The lines
cannot contact each other or other components. Do
not attempt to weld high-pressure fuel lines or to
repair lines that are damaged. Only use the recom-
mended lines when replacement of high-pressure
fuel line is necessary.
REMOVAL
High-pressure lines are used between the fuel
injection pump and the fuel injectors only. All high-
pressure fuel lines are of the same length and inside
diameter. Correct high-pressure fuel line usage and
installation is critical to smooth engine operation.
CAUTION: Refer to Cleaning Fuel System Parts.
(1) Disconnect both negative battery cables from
both batteries. Cover and isolate ends of cables.
(2) Thoroughly clean fuel lines at cylinder head
and injection pump ends.
(3) Remove cable cover (Fig. 39). Cable cover is
attached with 2 Phillips screws, 2 plastic retention
clips and 2 push tabs (Fig. 39). Remove 2 Phillips
screws and carefully pry out 2 retention clips. After
clip removal, push rearward on front tab, and
upward on lower tab for cover removal.Do not
remove any cables at lever.
(4) Disconnect wiring harness (clip) at bottom of
Accelerator Pedal Position Sensor (APPS) mounting
bracket (Fig. 40).(5) Using 2 small screwdrivers, pry front wiring
clip (Fig. 41) from cable bracket housing. Position
wiring harness towards front of engine.
Fig. 39 Cable/Lever/Throttle Linkage Cover
1 - CABLE/LEVER/LINKAGE COVER
2 - PUSH UP LOWER TAB
3 - SCREWS/CLIPS (2)
4 - TAB PUSH HERE
Fig. 40 Wiring Clip at APPS
1 - LEVER
2 - MOUNTING BOLTS (6)
3 - WIRE HARNESS CLIP
4 - CALIBRATION SCREWS (NO ADJUSTMENT)
5 - APPS ASSEMBLY
Fig. 41 Air Tube (Typical)
1 - ENGINE OIL DIPSTICK TUBE
2 - TUBE BOLT
3 - CLAMPS
4 - AIR TUBE (INTAKE MANIFOLD TO CHARGE AIR COOLER
5 - CABLE BRACKET HOUSING
6 - FRONT WIRING CLIP
7 - GROUND CABLE
8 - RUBBER HOSE
9 - AIR INTAKE HOUSING
BR/BEFUEL DELIVERY - DIESEL 14 - 75
FUEL LINES (Continued)

(3) Installrearinjection line bundle beginning
with cylinder head (fuel injector) connections, fol-
lowed by injection pump connections. Tighten all fit-
tings finger tight.
(4) Tighten fittings at fuel injector ends for cylin-
ders number 6 and 5 to 38 N´m (28 ft. lbs.) torque.
Do not tighten number 3 line at this time. It
will be tightened during bleeding procedure.
(5) Tighten 3 fittings at fuel injection pump ends
to 24 N´m (18 ft. lbs.) torque.
(6) Installfrontinjection line bundle beginning
with cylinder head (fuel injector) connections, fol-
lowed by injection pump connections. Tighten all fit-
tings finger tight.
(7) Tighten fitting at fuel injector end for cylinder
number 2 to 38 N´m (28 ft. lbs.) torque.Do not
tighten lines number 1 or 4 at this time. They
will be tightened during bleeding procedure.
(8) Tighten remaining 3 fittings at fuel injection
pump ends to 24 N´m (18 ft. lbs.) torque.
(9) Install fuel line support bracket bolts to intake
manifold and tighten to 24 N´m (18 ft. lbs.) torque.
CAUTION: Be sure fuel lines are not contacting
each other or any other component. Noise will
result.
(10) Install engine lifting bracket at rear of intake
manifold. Tighten 2 bolts to 77 N´m (57 ft. lbs.)
torque.
(11) Install cable bracket housing/cable assembly
and tighten 3 mounting bolts to 24 N´m (18 ft. lbs.)
torque.
(12) Clean any old gasket material below and
above intake manifold air heater element block. Also
clean mating areas at intake manifold and air intake
housing.
(13) Using new gaskets, position intake manifold
air heater element block to engine.
(14) Install air intake housing and position ground
cable. Install 4 mounting bolts and tighten to 24 N´m
(18 ft. lbs.) torque.
(15) Install air tube (intake manifold-to-charge air
cooler) (Fig. 41). Tighten clamps to 8 N´m (72 in. lbs.)
torque.
(16) Install engine oil dipstick tube support mount-
ing bolt and tighten to 24 N´m (18 ft. lbs.) torque.
(17) Install engine oil dipstick to engine.
(18) Connect 2 electrical cables to cable mounting
studs.
(19) Connect electrical connector to bottom of
APPS by pushing connector upward until it snaps
into position.
(20) Connect wiring harness (clip) at bottom of
Accelerator Pedal Position Sensor (APPS) mounting
bracket (Fig. 40).(21) Connect front wiring clip (Fig. 41) to cable
bracket housing.
(22) Install cable cover (Fig. 39).
(23) Connect both negative battery cables to both
batteries.
(24) Bleed air from fuel system. Do this at fuel
injector ends of lines. Use cylinders numbers 1, 3 and
4 for bleeding . (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY - STANDARD PROCEDURE). After
bleeding, tighten fittings to 38 N´m (28 ft. lbs.)
torque.
(25) Check lines/fittings for leaks.
FUEL TANK
DESCRIPTION - DIESEL FUEL TANK
The fuel tank is similar to the tank used with gas-
oline powered models. The tank is equipped with a
separate fuel return line and a different fuel tank
module for diesel powered models. A fuel tank
mounted, electric fuel pump is not used with diesel
powered models. Refer to Fuel Tank Module for addi-
tional information.
For removal and installation procedures, refer to
Fuel Tank - Gasoline Engines.
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 pump and the
fuel injection pump.
The fuel tank module is installed in the top of the
fuel tank (Fig. 48). The fuel tank module (Fig. 48)
contains the following components:
²Fuel reservoir
²A separate in-tank fuel filter
²Rollover valve
²Fuel gauge sending unit (fuel level sensor)
²Fuel supply line connection
²Fuel return line connection
²Auxiliary non-pressurized fuel supply 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.
14 - 78 FUEL DELIVERY - DIESELBR/BE
FUEL LINES (Continued)

The transfer pump is self-priming: When the key is
first turned on (without cranking engine), the pump
will operate for approximately 2 seconds 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. The valve is located
on the side of the injection pump (Fig. 52). It is also
used to connect the fuel return line to the side of the
injection pump. This valve opens at approximately 97
kPa (14 psi) and returns fuel to the fuel tank
through the fuel return line.
DIAGNOSIS AND TESTING - FUEL TRANSFER
PUMP PRESSURE
The following tests will include: pressures
tests of fuel transfer pump (engine running and
engine cranking), a pressure drop test of fuel
filter, a test for supply side restrictions, and a
test for air in fuel supply side.
Fig. 50 Fuel Transfer Pump Location
1 - OIL PRESSURE SENSOR
2 - PUMP BRACKET NUTS (3)
3 - SUPPORT BRACKET BOLT
4 - BANJO BOLT (REAR)
5 - FUEL SUPPLY LINE
6 - ELECTRICAL CONNECTOR
7 - BANJO BOLT (FRONT)
8 - FUEL TRANSFER PUMP
Fig. 51 Engine Control Module (ECM) Location
1 - ENGINE CONTROL MODULE (ECM)
2 - HEX HEADED BOLT
3 - 50-WAY CONNECTOR
4 - FUEL TRANSFER PUMP
5 - MOUNTING BOLTS (3)
Fig. 52 Injection Pump Overflow Valve Location
1 - FUEL SUPPLY LINE
2 - FUEL RETURN LINE
3 - BANJO BOLT (TEST PORT FITTING)
4 - OVERFLOW VALVE
5 - BANJO FITTING
14 - 80 FUEL DELIVERY - DIESELBR/BE
FUEL TRANSFER PUMP (Continued)