ABS DODGE RAM 2003 Service Repair Manual

(2) Disconnect negative battery cable from battery.
(3) Clean fitting of any foreign material before dis-
assembly.
(4)2±Button Type Fitting:This type of fitting is
equipped with a push-button located on each side of
quick-connect fitting (Fig. 5). Press on both buttons
simultaneously for removal. Special tools are not
required for disconnection.
(5)Pinch-Type Fitting:This fitting is equipped
with two finger tabs. Pinch both tabs together while
removing fitting (Fig. 6). Special tools are not
required for disconnection.
(6)Single-Tab Type Fitting:This type of fitting
is equipped with a single pull tab (Fig. 7). The tab is
removable. After tab is removed, quick-connect fitting
can be separated from fuel system component. Spe-
cial tools are not required for disconnection.
(a) Press release tab on side of fitting to release
pull tab (Fig. 8).If release tab is not pressed
prior to releasing pull tab, pull tab will be
damaged.
(b) While pressing release tab on side of fitting,
use screwdriver to pry up pull tab (Fig. 8).
(c) Raise pull tab until it separates from quick-
connect fitting (Fig. 9).
(7)Two-Tab Type Fitting:This type of fitting is
equipped with tabs located on both sides of fitting
(Fig. 10). The tabs are supplied for disconnecting
quick-connect fitting from component being serviced.
(a) To disconnect quick-connect fitting, squeeze
plastic retainer tabs (Fig. 10) against sides of
quick-connect fitting with your fingers. Tool use isnot required for removal and may damage plastic
retainer.
(b) Pull fitting from fuel system component
being serviced.
(c) The plastic retainer will remain on compo-
nent being serviced after fitting is disconnected.
The o-rings and spacer will remain in quick-con-
nect fitting connector body.
Fig. 5 2-BUTTON TYPE FITTING
1 - QUICK-CONNECT FITTING
2 - PUSH-BUTTONS (2)
Fig. 6 PINCH TYPE QUICK-CONNECT FITTING
1 - QUICK-CONNECT FITTINGS
2 - PINCH TABS
Fig. 7 SINGLE-TAB TYPE FITTING
1 - PULL TAB
2 - QUICK-CONNECT FITTING
3 - PRESS HERE TO REMOVE PULL TAB
4 - INSERTED TUBE END
DRFUEL DELIVERY - GAS 14 - 9
QUICK CONNECT FITTING (Continued)

Tank Removal
(1) Loosen clamp and disconnect rubber fuel vent
hose (Fig. 28) at tank fitting.
(2) Support tank with a hydraulic jack.
(3) Remove 2 fuel tank strap nuts (Fig. 29) and
remove both tank support straps.
(4) Carefully lower tank a few inches and discon-
nect fuel pump module electrical connector (Fig. 30)
at top of tank. To disconnect electrical connector:
Push upward on red colored tab to unlock. Push on
black colored tab while removing connector.(5) Disconnect fuel line at fuel filter / fuel pressure
regulator (Fig. 30) by pressing on tabs at side of
quick-connect fitting.
(6) Disconnect EVAP line at top of tank (Fig. 1).
(7) Continue to lower tank for removal.
(8) If fuel tank is to be replaced, remove fuel pump
module from tank. Refer to Fuel Pump Module
Removal/Installation procedures.
Fig. 28 FUEL TANK FILL / VENT HOSES
1 - BEZEL SCREWS
2 - FUEL FILL BEZEL
3 - HOSE CLAMPS4 - VENT HOSE
5 - FUEL TANK
6 - FILL HOSE
DRFUEL DELIVERY - GAS 14 - 21
FUEL TANK (Continued)

(13) Start engine and check for fuel leaks near top
of module.
INLET FILTER
REMOVAL
The fuel pump inlet filter (strainer) is located on
the bottom of the fuel pump module (Fig. 32). The
fuel pump module is located inside of fuel tank.
(1) Remove fuel tank. Refer to Fuel Tank Removal/
Installation.
(2) Remove fuel pump module. Refer to Fuel Pump
Module Removal/Installation.
(3) Remove filter by carefully prying 2 lock tabs at
bottom of module with 2 screwdrivers. Filter is
snapped to module.
(4) Clean bottom of pump module.
INSTALLATION
The fuel pump inlet filter (strainer) is located on
the bottom of the fuel pump module (Fig. 32). The
fuel pump module is located inside of fuel tank.
(1) Snap new filter to bottom of module. Be sure
o-ring is in correct position.
(2) Install fuel pump module. Refer to Fuel Pump
Module Removal/Installation.
(3) Install fuel tank. Refer to Fuel Tank Removal/
Installation.
Fig. 30 FUEL PUMP MODULE CONNECTIONS
1 - TOP OF FUEL TANK
2 - FUEL PUMP MODULE
3 - FUEL FILTER / FUEL PRESSURE REGULATOR
4 - ELEC. CONNECT.
Fig. 31 HOSE ALIGNMENT MARKS
1 - ALIGNMENT MARKS (MARK FOR FILL HOSE IS LOCATED
ON FUEL TANK - MARK FOR VENT HOSE IS LOCATED ON
FITTING)
2 - PAINT MARKS ON RUBBER HOSES
Fig. 32 FUEL PUMP INLET FILTER
1 - FUEL PUMP INLET FILTER
2 - LOCK TABS (2)
3 - FUEL PUMP MODULE (BOTTOM)
DRFUEL DELIVERY - GAS 14 - 23
FUEL TANK (Continued)

(1) Install sensor to intake manifold. Tighten to
12±15 N´m (110±130 in. lbs.) torque.
(2) Install electrical connector.
MAP SENSOR
DESCRIPTION
3.7L V-6
The Manifold Absolute Pressure (MAP) sensor is
mounted into the front of the intake manifold with 2
screws.
4.7L V-8
The Manifold Absolute Pressure (MAP) sensor is
mounted into the front of the intake manifold with 2
screws.
5.7L V-8
The Manifold Absolute Pressure (MAP) sensor is
mounted to the front of the intake manifold air ple-
num box.
5.9L V-8
The Manifold Absolute Pressure (MAP) sensor is
mounted to the front of the throttle body with 2
screws.
8.0L V-10
The Manifold Absolute Pressure (MAP) sensor is
mounted into the right side of the intake manifold.
OPERATION
The MAP sensor is used as an input to the Power-
train Control Module (PCM). It contains a silicon
based sensing unit to provide data on the manifold
vacuum that draws the air/fuel mixture into the com-
bustion chamber. The PCM requires this information
to determine injector pulse width and spark advance.
When manifold absolute pressure (MAP) equals
Barometric pressure, the pulse width will be at max-
imum.
A 5 volt reference is supplied from the PCM and
returns a voltage signal to the PCM that reflects
manifold pressure. The zero pressure reading is 0.5V
and full scale is 4.5V. For a pressure swing of 0±15
psi, the voltage changes 4.0V. To operate the sensor,
it is supplied a regulated 4.8 to 5.1 volts. Ground is
provided through the low-noise, sensor return circuit
at the PCM.
The MAP sensor input is the number one contrib-
utor to fuel injector pulse width. The most important
function of the MAP sensor is to determine baromet-
ric pressure. The PCM needs to know if the vehicle is
at sea level or at a higher altitude, because the airdensity changes with altitude. It will also help to cor-
rect for varying barometric pressure. Barometric
pressure and altitude have a direct inverse correla-
tion; as altitude goes up, barometric goes down. At
key-on, the PCM powers up and looks at MAP volt-
age, and based upon the voltage it sees, it knows the
current barometric pressure (relative to altitude).
Once the engine starts, the PCM looks at the voltage
again, continuously every 12 milliseconds, and com-
pares the current voltage to what it was at key-on.
The difference between current voltage and what it
was at key-on, is manifold vacuum.
During key-on (engine not running) the sensor
reads (updates) barometric pressure. A normal range
can be obtained by monitoring a known good sensor.
As the altitude increases, the air becomes thinner
(less oxygen). If a vehicle is started and driven to a
very different altitude than where it was at key-on,
the barometric pressure needs to be updated. Any
time the PCM sees Wide Open Throttle (WOT), based
upon Throttle Position Sensor (TPS) angle and RPM,
it will update barometric pressure in the MAP mem-
ory cell. With periodic updates, the PCM can make
its calculations more effectively.
The PCM uses the MAP sensor input to aid in cal-
culating the following:
²Manifold pressure
²Barometric pressure
²Engine load
²Injector pulse-width
²Spark-advance programs
²Shift-point strategies (certain automatic trans-
missions only)
²Idle speed
²Decel fuel shutoff
The MAP sensor signal is provided from a single
piezoresistive element located in the center of a dia-
phragm. The element and diaphragm are both made
of silicone. As manifold pressure changes, the dia-
phragm moves causing the element to deflect, which
stresses the silicone. When silicone is exposed to
stress, its resistance changes. As manifold vacuum
increases, the MAP sensor input voltage decreases
proportionally. The sensor also contains electronics
that condition the signal and provide temperature
compensation.
The PCM recognizes a decrease in manifold pres-
sure by monitoring a decrease in voltage from the
reading stored in the barometric pressure memory
cell. The MAP sensor is a linear sensor; meaning as
pressure changes, voltage changes proportionately.
The range of voltage output from the sensor is usu-
ally between 4.6 volts at sea level to as low as 0.3
volts at 26 in. of Hg. Barometric pressure is the pres-
sure exerted by the atmosphere upon an object. At
sea level on a standard day, no storm, barometric
DRFUEL INJECTION - GAS 14 - 39
INTAKE AIR TEMPERATURE SENSOR (Continued)

pressure is approximately 29.92 in Hg. For every 100
feet of altitude, barometric pressure drops 0.10 in.
Hg. If a storm goes through, it can change baromet-
ric pressure from what should be present for that
altitude. You should know what the average pressure
and corresponding barometric pressure is for your
area.
REMOVAL
3.7L V-6
The Manifold Absolute Pressure (MAP) sensor is
mounted into the front of the intake manifold (Fig.
31). An o-ring is used to seal the sensor to the intake
manifold (Fig. 32).
(1) Disconnect electrical connector at sensor.
(2) Clean area around MAP sensor.
(3) Remove 2 sensor mounting screws.
(4) Remove MAP sensor from intake manifold.
(5) Check condition of sensor o-ring (Fig. 32).
4.7L V-8
The MAP sensor is located on the front of the
intake manifold (Fig. 33). An o-ring seals the sensor
to the intake manifold.
(1) Disconnect electrical connector at sensor.
(2) Clean area around MAP sensor.
(3) Remove 2 sensor mounting bolts (Fig. 33).
(4) Remove MAP sensor from intake manifold.(5) Check condition of sensor o-ring (Fig. 32).
Fig. 31 MAP SENSOR - 3.7L V-6
1 - MOUNTING SCREWS
2 - MAP SENSOR
3 - ECT SENSOR
4 - FRONT OF INTAKE MANIFOLD
Fig. 32 MAP SENSOR O-RING 3.7L / 4.7L
1 - MAP SENSOR
2 - O-RING
Fig. 33 MAP SENSOR - 4.7L V-8
1 - ECT SENSOR
2 - MOUNTING BOLTS (2)
3 - MAP SENSOR
4 - INTAKE MANIFOLD
14 - 40 FUEL INJECTION - GASDR
MAP SENSOR (Continued)

5.7L V-8
The Manifold Absolute Pressure (MAP) sensor is
mounted to the front of the intake manifold air ple-
num box (Fig. 34).
(1) Disconnect electrical connector at sensor by
sliding release lock out (Fig. 35). Press down on lock
tab for removal.
(2) Rotate sensor 1/4 turn counter-clockwise for
removal.
(3) Check condition of sensor o-ring.
5.9L V-8
The MAP sensor is located on the front of the
throttle body (Fig. 36). An L-shaped rubber fitting is
used to connect the MAP sensor to throttle body (Fig.
37).
(1) Clean area around MAP sensor.
(2) Remove two MAP sensor mounting bolts
(screws) (Fig. 36).
(3) While removing MAP sensor, slide the vacuum
rubber L-shaped fitting (Fig. 37) from the throttle
body.
(4) Remove rubber L-shaped fitting from MAP sen-
sor.
8.0L V-10
The MAP sensor is mounted into the right upper
side of intake manifold (Fig. 38). A rubber gasket is
used to seal sensor to intake manifold. The rubber
gasket is part of sensor and is not serviced sepa-
rately.(1) Remove electrical connector at sensor.
(2) Clean area around sensor before removal.
(3) Remove two sensor mounting bolts.
(4) Remove sensor from intake manifold.
Fig. 34 5.7L MAP SENSOR LOCATION
1 - MAP SENSOR
2 - FRONT OF INTAKE MANIFOLD
Fig. 35 5.7L MAP SENSOR R/I
1 - PRESS DOWN
2 - SLIDE RELEASE LOCK
3 - MAP SENSOR
Fig. 36 MAP SENSOR - 5.9L V-8
1 - MAP SENSOR
2 - MOUNTING SCREWS (2)
DRFUEL INJECTION - GAS 14 - 41
MAP SENSOR (Continued)

INSTALLATION
3.7L V-6
The Manifold Absolute Pressure (MAP) sensor is
mounted into the front of the intake manifold (Fig.
31). An o-ring is used to seal the sensor to the intake
manifold (Fig. 32).
(1) Clean MAP sensor mounting hole at intake
manifold.
(2) Check MAP sensor o-ring seal for cuts or tears.
(3) Position sensor into manifold.(4) Install MAP sensor mounting bolts (screws).
Refer to Torque Specifications.
(5) Connect electrical connector.
4.7L V-8
The MAP sensor is located on the front of the
intake manifold (Fig. 33). An o-ring seals the sensor
to the intake manifold (Fig. 32).
(1) Clean MAP sensor mounting hole at intake
manifold.
(2) Check MAP sensor o-ring seal for cuts or tears.
(3) Position sensor into manifold.
(4) Install MAP sensor mounting bolts (screws).
Refer to Torque Specifications.
(5) Connect electrical connector.
5.7L V-8
The Manifold Absolute Pressure (MAP) sensor is
mounted to the front of the intake manifold air ple-
num box (Fig. 34).
(1) Clean MAP sensor mounting hole at intake
manifold.
(2) Check MAP sensor o-ring seal for cuts or tears.
(3) Position sensor into manifold.
(4) Rotate sensor 1/4 turn clockwise for installa-
tion.
(5) Connect electrical connector.
5.9L V-8
The MAP sensor is located on the front of the
throttle body (Fig. 36). An L-shaped rubber fitting is
used to connect the MAP sensor to throttle body (Fig.
37).
(1) Install rubber L-shaped fitting to MAP sensor.
(2) Position sensor to throttle body while guiding
rubber fitting over throttle body vacuum nipple.
(3) Install MAP sensor mounting bolts (screws).
Refer to Torque Specifications.
(4) Install air resonator box.
8.0L V-10
The MAP sensor is mounted into the right upper
side of intake manifold (Fig. 38). A rubber gasket is
used to seal sensor to intake manifold. The rubber
gasket is part of sensor and is not serviced sepa-
rately.
(1) Check condition of sensor seal. Clean sensor
and lubricate rubber gasket with clean engine oil.
(2) Clean sensor opening in intake manifold.
(3) Install sensor into intake manifold.
(4) Install sensor mounting bolts. Refer to Torque
Specifications.
(5) Install electrical connector to sensor.
Fig. 37 MAP SENSOR L-SHAPED RUBBER FITTING
- 5.9L V-8
1 - MAP SENSOR
2 - RUBBER FITTING
3 - IDLE AIR PASSAGE
Fig. 38 MAP SENSOR LOCATION - 8.0L V-10
1 - MAP SENSOR
2 - MOUNTING BOLTS
3 - THROTTLE BODY
14 - 42 FUEL INJECTION - GASDR
MAP SENSOR (Continued)

8.0L V-10
CAUTION: Be careful not to damage or kink cable
core wire (within cable sheathing) while servicing
accelerator pedal or cables.
(1) From inside vehicle, hold up accelerator pedal.
Remove plastic cable retainer and throttle cable core
wire from upper end of pedal arm (Fig. 1). The plas-
tic cable retainer snaps into pedal arm.
(2) Remove cable core wire at pedal arm.(3) Remove necessary air intake tubes and resona-
tor housing.
(4) From inside vehicle, pinch both sides of plastic
cable housing retainer tabs at dash panel (Fig. 1).
(5) Remove cable housing from dash panel and
pull cable into engine compartment.
(6) Remove throttle cable socket at throttle lever
ball (Fig. 55) (snaps off).
(7) Remove cable housing at throttle body mount-
ing bracket by pressing on release tab with a small
screwdriver (Fig. 55).To prevent cable housing
breakage, press on tab only enough to release
cable from bracket.Lift cable housing straight up
from bracket while pressing on release tab. Remove
throttle cable from vehicle.
INSTALLATION
3.7L V-6
(1) Slide accelerator cable plastic mount into throt-
tle body mounting bracket. Continue sliding until
release tab (Fig. 50) is aligned to hole in mounting
bracket.
(2) Hold throttle in wide open position. While held
in this position, slide throttle cable pin (Fig. 49) into
throttle body bellcrank.
(3) Push cable housing into rubber grommet and
through opening in dash panel.
Fig. 53 THROTTLE CABLE AT THROTTLE BODY -
5.9L
1 - THROTTLE LEVER PIN
2 - CAM (V-8 ENGINE ONLY)
3 - THROTTLE CABLE END
Fig. 54 CABLE RELEASE - 5.9L V-8
1-TAB
Fig. 55 THROTTLE CABLE AT THROTTLE BODY -
8.0L V-10
1 - PRESS TAB FOR CABLE REMOVAL
2 - THROTTLE CABLE
3 - CABLE SOCKET
4 - LEVER BALL
5 - MOUNTING BRACKET
DRFUEL INJECTION - GAS 14 - 51
THROTTLE CONTROL CABLE (Continued)

(4) From inside vehicle, install metal clip holding
cable to dashpanel (Fig. 1).
(5) From inside vehicle, slide throttle cable core
wire into opening (slot) in top of pedal arm.
(6) Push plastic cable retainer (clip) into pedal arm
opening until it snaps in place.
(7) Install air resonator tube to throttle body.
(8) Before starting engine, operate accelerator
pedal to check for any binding.
4.7L V-8
(1) Slide accelerator cable plastic mount into
bracket. Continue sliding until tab (Fig. 52) is
aligned to hole in mounting bracket.
(2) Route accelerator cable over top of cable cam.
(3) Connect cable end to throttle body bellcrank
pin (snaps on rearward).
(4) Slide rubber grommet away from plastic cable
housing.
(5) Install rubber grommet into dash panel until
seated.
(6) Push cable housing into rubber grommet and
through opening in dash panel.
(7) From inside vehicle, install clip holding cable
to dashpanel (Fig. 1).
(8) From inside vehicle, slide throttle cable core
wire into opening in top of pedal arm.
(9) Push cable retainer (clip) into pedal arm open-
ing until it snaps in place.
(10) Snap cable into dashpanel routing clip.
(11) Install air resonator tube to throttle body.
(12) Before starting engine, operate accelerator
pedal to check for any binding.
5.7L V-8
(1) Attach cable to Accelerator Pedal Position Sen-
sor (APPS). Refer to APPS Removal / Installation.
(2) Push cable housing into rubber grommet and
through opening in dash panel.
(3) From inside vehicle, install clip holding cable
to dashpanel (Fig. 1).
(4) From inside vehicle, slide throttle cable core
wire into opening in top of pedal arm.
(5) Push cable retainer (clip) into pedal arm open-
ing until it snaps in place.
(6) Before starting engine, operate accelerator
pedal to check for any binding.
(7) If necessary, use DRB IIItScan Tool to erase
any APPS Diagnostic Trouble Codes (DTC's) from
PCM.
5.9L V-8
(1) Slide accelerator cable plastic mount into throt-
tle body mounting bracket. Continue sliding until
release tab (Fig. 54) is aligned to hole in mounting
bracket.(2) Hold throttle in wide open position. While held
in this position, slide throttle cable pin into throttle
body bellcrank.
(3) Push cable housing into rubber grommet and
through opening in dash panel.
(4) From inside vehicle, install metal clip holding
cable to dashpanel (Fig. 1).
(5) From inside vehicle, slide throttle cable core
wire into opening (slot) in top of pedal arm.
(6) Push plastic cable retainer (clip) into pedal arm
opening until it snaps in place.
(7) Install air resonator tube to throttle body.
(8) Before starting engine, operate accelerator
pedal to check for any binding.
8.0L V-10
(1) Connect cable end socket to throttle body lever
ball (snaps on) (Fig. 55).
(2) Connect cable to throttle body mounting
bracket (push down and lock)
(3) Install the remaining cable housing end into
and through the dash panel opening (snaps into posi-
tion). The two plastic pinch tabs (Fig. 1) should lock
the cable to dash panel.
(4) From inside the vehicle, hold up the accelera-
tor pedal. Install the throttle cable core wire and
plastic cable retainer into and through the upper end
of the pedal arm (the plastic retainer is snapped into
the pedal arm). When installing the plastic retainer
to the accelerator pedal arm, note the index tab on
the pedal arm (Fig. 1). Align the index slot on the
plastic cable retainer to this index tab.
(5) Install air resonator tube to throttle body.
(6) Before starting engine, operate accelerator
pedal to check for any binding.
THROTTLE POSITION SENSOR
DESCRIPTION
The 3-wire Throttle Position Sensor (TPS) is
mounted on the throttle body and is connected to the
throttle blade shaft.
The 5.7L V-8 engine does not use a separate TPS
on the throttle body.
OPERATION
The 5.7L V-8 engine does not use a separate Throt-
tle Position Sensor (TPS) on the throttle body.
The 3±wire TPS provides the Powertrain Control
Module (PCM) with an input signal (voltage) that
represents the throttle blade position of the throttle
body. The sensor is connected to the throttle blade
shaft. As the position of the throttle blade changes,
the output voltage of the TPS changes.
14 - 52 FUEL INJECTION - GASDR
THROTTLE CONTROL CABLE (Continued)

(4) Apply clean engine oilto injection pump
o-ring only.
The machined tapers on both injection pump
shaft and injection pump gear must be abso-
lutely dry, clean and free of any dirt or oil film.
This will ensure proper gear-to-shaft tighten-
ing.
(5) Clean pump gear and pump shaft at machined
tapers with an evaporative type cleaner such as
brake cleaner.
(6) Position injection pump to mounting flange on
gear cover while aligning injection pump shaft
through back of injection pump gear.
(7) After pump is positioned flat to mounting
flange, install 3 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. Dam-
age to pump or gear cover may occur. The
pump must be positioned flat to its mounting
flange before attempting to tighten 3 mounting
nuts.
(8) To prevent damage or cracking of components,
install and tighten nuts in the following sequence:
(a) Install injection pump shaft washer and nut
to pump shaft. Tighten nutfinger tight only.
(b) Do preliminary (light) tightening of injection
pump shaft nut.
(c) Tighten 3 injection pump mounting nuts to 8
N´m (70.8 in. lbs.).
(d) Do a final tightening of pump shaft nut to
105 N´m (77 ft. lbs.).
(9) Install drive gear access cover (plate) using a
1/2 inch drive ratchet. Plate is threaded to timing
gear cover.
(10) Install Engine Control Module (ECM) to left
side of engine.
(11) Install fuel line (injection pump-to-overflow
valve). Tighten bolts to 24 N´m (17 ft. lbs.) torque.
(12) Install fuel line (injection pump-to-fuel rail).
Tighten to 24 N´m (17 ft. lbs.) torque.
(13) Install fuel line (injection pump-to-fuel filter
housing). Tighten to 24 N´m (17 ft. lbs.) torque.
(14) Connect Fuel Control Actuator (FCA) electri-
cal connector to rear of injection pump.
(15) Install intake manifold air intake tube (above
injection pump). Tighten clamps.
(16) Install accessory drive belt.
(17) Install cooling fan shroud.
(18) Install cooling fan assembly.
(19) Connect both negative battery cables to both
batteries.
(20) Check system for fuel or engine oil leaks.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
ECM through the sensor return circuit.
Both of the electrical circuits between the fuel
gauge sending unit and the ECM are hard-wired (not
multi-plexed). After the voltage signal is sent from
the resistor track, and back to the ECM, the ECM
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.
REMOVAL
REMOVAL/INSTALLATION
For diesel removal and installation procedures,
refer to the gas section of Fuel System/Fuel Delivery.
See Fuel Level Sending Unit/Sensor Removal/Instal-
lation.
14 - 68 FUEL DELIVERY - DIESELDR
FUEL INJECTION PUMP (Continued)