1998 DODGE RAM 1500 control arm

(4) Remove air resonator box at throttle body.
(5) Unsnap cable from dashpanel routing clip.
(6) Remove cable housing from dash panel and
pull into engine compartment.
(7) Hold throttle in wide open position. While held
in this position, slide throttle cable pin (Fig. 33) from
throttle body bellcrank.
(8) Using a pick or small screwdriver, press release
tab (Fig. 34) to release plastic cable mount from
bracket.Press on tab only enough to release
cable from bracket. If tab is pressed too much,
it will be broken.Slide plastic mount (Fig. 34)
towards right side of vehicle to remove throttle cable
from throttle body bracket.
(9) Remove throttle cable from vehicle.
4.7L V-8
CAUTION: Be careful not to damage or kink cable
core wire (within cable sheathing) while servicing
accelerator pedal or throttle cable.
(1) From inside vehicle, hold up accelerator pedal.
Remove plastic cable retainer (clip) and throttle cable
core wire from upper end of pedal arm (Fig. 1). Plas-
tic cable retainer (clip) snaps into pedal arm.
(2) Remove cable core wire at pedal arm.
(3) From inside vehicle, remove cable clip holding
cable to dashpanel (Fig. 1).
(4) Remove air box at throttle body.
(5) Unsnap cable from dashpanel routing clip.
(6) Remove cable housing from dash panel and
pull into engine compartment.(7) Using finger pressure only, disconnect accelera-
tor cable connector at throttle body bellcrank pin by
pushing connector off bellcrank pin towards front of
vehicle (Fig. 35).DO NOT try to pull connector
off perpendicular to bellcrank pin. Connector
will be broken.
(8) Lift accelerator cable from top of cable cam
(Fig. 35).
(9) Press tab (Fig. 36) to release plastic cable
mount from bracket.Press on tab only enough to
release cable from bracket. If tab is pressed too
much, it will be broken.Slide plastic mount (Fig.
36) towards passenger side of vehicle to remove cable
from bracket.
(10) Remove throttle cable from vehicle.5.7L V-8
The Throttle Control Cable on the 5.7L V-8 engine
connects the accelerator pedal to the Accelerator
Pedal Position Sensor (APPS). A separate mechanical
cable is not routed to the throttle body.
CAUTION: Be careful not to damage or kink cable
core wire (within cable sheathing) while servicing
accelerator pedal, cables or APPS.
(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.
Fig. 33 THROTTLE CABLE PIN - 3.7L V-6
1 - THROTTLE CABLE PIN
2 - THROTTLE BODY BELLCRANK
3 - PUSH UP HERE
Fig. 34 THROTTLE CABLE RELEASE TAB - 3.7L V-6
1 - THROTTLE CABLE
2 - RELEASE TAB
3 - PICK OR SCREWDRIVER
4 - PLASTIC CABLE MOUNT
DRFUEL INJECTION - GAS 14 - 39
THROTTLE CONTROL CABLE (Continued)

(3) Remove APPS. Refer to Accelerator Pedal Posi-
tion Sensor (APPS) Removal / Installation.
(4) From inside vehicle, remove cable clip (Fig. 1).
(5) Remove cable housing from dash panel and
pull cable into engine compartment.
(6) Remove cable housing at APPS bracket by
pressing on release tab with a small screwdriver.To
prevent cable housing breakage, press on tab
only enough to release cable from APPS
bracket.
INSTALLATION
3.7L V-6
(1) Slide accelerator cable plastic mount into throt-
tle body mounting bracket. Continue sliding until
release tab (Fig. 34) is aligned to hole in mounting
bracket.
(2) Hold throttle in wide open position. While held
in this position, slide throttle cable pin (Fig. 33) 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.
4.7L V-8
(1) Slide accelerator cable plastic mount into
bracket. Continue sliding until tab (Fig. 36) 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.
Fig. 35 ACCELERATOR CABLE AT BELL CRANK -
4.7L V-8
1 - THROTTLE BODY
2 - SPEED CONTROL CABLE CONNECTOR
3 - OFF
4 - OFF
5 - ACCELERATOR CABLE CONNECTOR
6 - CABLE CAM
7 - BELLCRANK
Fig. 36 ACCELERATOR CABLE RELEASE TAB -
4.7L V-8
1 - ACCELERATOR CABLE
2 - PLASTIC CABLE MOUNT
3 - PRESS TAB FOR REMOVAL
4 - CABLE BRACKET
5 - SLIDE FOR REMOVAL
14 - 40 FUEL INJECTION - GASDR
THROTTLE CONTROL CABLE (Continued)

(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.
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.
The PCM supplies approximately 5 volts to the
TPS. The TPS output voltage (input signal to the
PCM) represents the throttle blade position. The
PCM receives an input signal voltage from the TPS.
This will vary in an approximate range of from .26
volts at minimum throttle opening (idle), to 4.49 volts
at wide open throttle. Along with inputs from other
sensors, the PCM uses the TPS input to determine
current engine operating conditions. In response to
engine operating conditions, the PCM will adjust fuel
injector pulse width and ignition timing.The PCM needs to identify the actions and position
of the throttle blade at all times. This information is
needed to assist in performing the following calcula-
tions:
²Ignition timing advance
²Fuel injection pulse-width
²Idle (learned value or minimum TPS)
²Off-idle (0.06 volt)
²Wide Open Throttle (WOT) open loop (2.608
volts above learned idle voltage)
²Deceleration fuel lean out
²Fuel cutoff during cranking at WOT (2.608 volts
above learned idle voltage)
²A/C WOT cutoff (certain automatic transmis-
sions only)
REMOVAL
3.7L V6
The Throttle Position Sensor (TPS) is mounted to
the throttle body (Fig. 37), or (Fig. 38).
(1) Remove air resonator tube at throttle body.
(2) Disconnect TPS electrical connector.
(3) Remove 2 TPS mounting screws.
(4) Remove TPS.
Fig. 37 TPS LOCATION - 3.7L V-6
1 - THROTTLE POSITION SENSOR (TPS)
2 - MOUNTING SCREWS
3 - IDLE AIR CONTROL MOTOR (IAC)
4 - MOUNTING SCREWS
DRFUEL INJECTION - GAS 14 - 41
THROTTLE CONTROL CABLE (Continued)

The fuel heater element and fuel heater relay
are not computer controlled.
The heater element operates on 12 volts, 300 watts
at 0 degrees F.
DIAGNOSIS AND TESTING - FUEL HEATER
The fuel heater is used to prevent diesel fuel from
waxing during cold weather operation.
NOTE: The fuel heater element, fuel heater relay
and fuel heater temperature sensor are not con-
trolled by the Engine Control Module (ECM).
A malfunctioning fuel heater can cause a wax
build-up in the fuel filter/water separator. Wax
build-up in the filter/separator can cause engine
starting problems and prevent the engine from rev-
ving up. It can also cause blue or white fog-like
exhaust. If the heater is not operating in cold tem-
peratures, the engine may not operate due to fuel
waxing.
The fuel heater assembly is located on the side of
fuel filter housing.
The heater assembly is equipped with a built-in
fuel temperature sensor (thermostat) that senses fuel
temperature. When fuel temperature drops below 45
degrees   8 degrees F, the sensor allows current to
flow to built-in heater element to warm fuel. When
fuel temperature rises above 75 degrees   8 degrees
F, the sensor stops current flow to heater element
(circuit is open).
Voltage to operate fuel heater element is supplied
from ignition switch, through fuel heater relay (also
refer to Fuel Heater Relay), to fuel temperature sen-
sor and on to fuel heater element.
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 from thermostat
(Fig. 3).
Ambient temperature must be below the circuit
close temperature. If necessary, induce this ambient
temperature by placing ice packs on thermostat to
produce an effective ambient temperature below cir-
cuit close temperature.
Measure resistance across two pins. Operating
range is 0.3 Ð 0.45 Ohms.
(2) If resistance is out of range, remove thermostat
and check resistance across terminal connections of
heater. The heater can be checked at room tempera-
ture. Operating range is 0.3 - 0.45 Ohms.(3) Replace heater if resistance is not within oper-
ating range.
(4) If heater is within operating range, replace
heater thermostat.
REMOVAL
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. 5). 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.
REMOVAL
The fuel heater relay is located in the Power Dis-
tribution Center (PDC) (Fig. 6). Refer to label under
PDC cover for relay location.
(1) Remove PDC cover.
(2) Remove relay from PDC.
Fig. 5 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
14 - 52 FUEL DELIVERY - DIESELDR
FUEL HEATER (Continued)

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 2 different circuits (wires). Two of these circuits
are used at the fuel gauge sending unit for fuel
gauge operation. 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 Engine Control
Module (ECM).NOTE: For diagnostic purposes,
this 12V power source can only be verified with
the circuit opened (fuel tank module electrical
connector unplugged). With the connectors
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 voltage (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.
FUEL LINES
DESCRIPTION
Low-Pressure Lines Are:
²the fuel supply line from fuel tank to fuel trans-
fer (lift) pump.
²the fuel return line back to fuel tank.
²the fuel drain (manifold) line at rear of cylinder
head.
²the fuel supply line from fuel filter to fuel injec-
tion pump.
²the fuel injection pump return line.
High-Pressure Lines Are:
²the fuel line from fuel injection pump to fuel
rail.
²the 6 fuel lines from fuel rail up to injector con-
nector tubes
WARNING: HIGH-PRESSURE FUEL LINES DELIVER
DIESEL FUEL UNDER EXTREME PRESSURE FROM
THE INJECTION PUMP TO THE FUEL INJECTORS.
THIS MAY BE AS HIGH AS 160,000 KPA (23,206
PSI). USE EXTREME CAUTION WHEN INSPECTING
FOR HIGH-PRESSURE FUEL LEAKS. INSPECT FOR
HIGH-PRESSURE FUEL LEAKS WITH A SHEET OF
CARDBOARD. HIGH FUEL INJECTION PRESSURE
CAN CAUSE PERSONAL INJURY IF CONTACT IS
MADE WITH THE SKIN.
OPERATION
High-Pressure Lines
CAUTION: The high-pressure fuel lines must be
held securely in place in their 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. If lines are ever
kinked or bent, they must be replaced. Use only the
recommended lines when replacement of high-pres-
sure fuel line is necessary.
High-pressure fuel lines deliver fuel (under pres-
sure) of up to approximately 160,000 kPa (23,206
PSI) from the injection pump to the fuel injectors.
The lines expand and contract from the high-pres-
sure fuel pulses generated during the injection pro-
cess. 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.
DRFUEL DELIVERY - DIESEL 14 - 57

CAUTION: Do not attempt to remove sensor from
its mounting bracket as electronic calibration will
be destroyed (sensor-to-bracket mounting screws
are permanently attached). Two accelerator lever
set screws (Fig. 3) are used to position lever. Do
not attempt to alter positions of these set screws as
electronic calibration will be destroyed.
(1) Disconnect both negative battery cables at both
batteries.
(2) Remove cable cover (Fig. 1). Cable cover is
attached with 2 Phillips screws, 2 plastic retention
clips and 2 push tabs (Fig. 1). 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.
(3) Using finger pressure only, disconnect end of
speed control servo cable from throttle lever pin by
pulling forward on connector while holding lever
rearward (Fig. 2).DO NOT try to pull connector
off perpendicular to lever pin. Connector will
be broken.
(4) Using two small screwdrivers, pry throttle
cable connector socket from throttle lever ball (Fig.
2).Be very careful not to bend throttle lever
arm.
(5) Disconnect transmission control cable at lever
arm (if equipped). Refer to 21, Transmission.
(6) Squeeze pinch tabs on speed control cable (Fig.
2) and pull cable rearward to remove from cable
mounting bracket.
(7) Squeeze pinch tabs on throttle cable (Fig. 2)
and pull cable rearward to remove from cable mount-
ing bracket.
(8) Refer to 21, Transmission for transmission con-
trol cable removal procedures.
(9) Disconnect wiring harness clip (Fig. 3) at bot-
tom of bracket.
(10) Remove 6 mounting bolts (Fig. 3) and par-
tially remove APPS assembly from engine. After
assembly is partially removed, disconnect electrical
connector from bottom of sensor by pushing on con-
nector tab (Fig. 4).
(11) Remove APPS assembly from engine.
Battery Tray Mounted Sensor :
The APPS is serviced (replaced) as one assembly
including the sensor, plastic housing and cable. The
APPS assembly is located under the left (drivers
side) vehicle battery tray (Fig. 5). Access to APPS is
gained from over top of left / front tire.
(1) Disconnect negative battery cable at battery.
(2) Disconnect APPS cable at accelerator pedal.
Refer to Accelerator Pedal Removal / Installation.
(3) Remove wheel house liner at left / front wheel.
Refer to Body.(4) Gain access to APPS electrical connector by
opening swing-down door (Fig. 6). Disconnect electri-
cal connector.
(5) Remove 3 mounting bolts (Fig. 6).
(6) Remove APPS assembly from battery tray.
Fig. 1 CABLE/LEVER/THROTTLE LINKAGE COVER
1 - CABLE/LEVER/LINKAGE COVER
2 - PUSH UP LOWER TAB
3 - SCREWS/CLIPS (2)
4 - TAB PUSH HERE
Fig. 2 SERVO CABLE AT THROTTLE LEVER
1 - PINCH (2) TABS
2 - CABLE MOUNTING BRACKET
3 - PINCH TABS (2)
4 - OFF
5 - THROTTLE CABLE
6 - THROTTLE LEVER
7 - THROTTLE LEVER PIN
8 - OFF
9 - CONNECTOR
10 - SPEED CONTROL CABLE
DRFUEL INJECTION - DIESEL 14 - 69
ACCELERATOR PEDAL POSITION SENSOR (Continued)

is the primary engine speed indicator for the engine
after the engine is running.
REMOVAL
The Camshaft Position Sensor (CMP) on the 5.9L
diesel engine is located below the fuel injection
pump. It is bolted to the back of the timing gear
housing (Fig. 9).
(1) Disconnect electrical connector at CMP sensor
(Fig. 9).
(2) Remove sensor mounting bolt.
(3) Carefully twist sensor from timing gear hous-
ing.
(4) Check condition of sensor o-ring.
INSTALLATION
(1) Clean out machined hole in back of timing gear
housing (cover).
(2) Apply a small amount of engine oil to sensor
o-ring.
(3) Install sensor into timing gear housing (cover)
with a slight rocking action. Do not twist sensor into
position as damage to o-ring may result.
CAUTION: Before tightening sensor mounting bolt,
be sure sensor is completely flush to back of timingchain housing (cover). If sensor is not flush, dam-
age to sensor mounting tang may result.
(4) Install mounting bolt and tighten. Refer to
Torque Specifications.
(5) Connect electrical connector to sensor.
CRANKSHAFT POSITION
SENSOR
DESCRIPTION
The Crankshaft Position Sensor (CKP) on the die-
sel engine is attached at the front / left side of the
engine next to the engine harmonic balancer (crank-
shaft damper).
OPERATION
The Crankshaft Position Sensor (CKP) is the pri-
mary engine speed indicator for the engine after the
engine is running (Fig. 10). The CKP contains a hall
effect device. A rotating, notched target wheel (tone-
wheel) for the CKP is located on the engine harmonic
balancer (Fig. 11). This hall effect device detects
notches located on the tonewheel. As the tonewheel
rotates, the notches pass the tip of the CKP.
Fig. 8 5.9L DIESEL CMP
1 - CMP
2 - FUEL INJECTION PUMP (BOTTOM)
3 - ELECTRONIC CONTROL MODULE (ECM)
4 - ECM ELEC. CONNECTOR
5 - CMP ELEC. CONNECTOR
6 - CMP MOUNTING BOLT
7 - BACK OF TIMING GEAR HOUSING
Fig. 9 5.9L DIESEL CMP
1 - CMP
2 - FUEL INJECTION PUMP (BOTTOM)
3 - ELECTRONIC CONTROL MODULE (ECM)
4 - ECM ELEC. CONNECTOR
5 - CMP ELEC. CONNECTOR
6 - CMP MOUNTING BOLT
7 - BACK OF TIMING GEAR HOUSING
14 - 72 FUEL INJECTION - DIESELDR
CAMSHAFT POSITION SENSOR (Continued)

When the leading edge of the tonewheel notch
passes the tip of the CKP, the following occurs: The
interruption of magnetic field causes the voltage to
switch high resulting in a signal of approximately 5
volts.
When the trailing edge of the tonewheel notch
passes the tip of the CKP, the following occurs: The
change of the magnetic field causes the signal voltage
to switch low to 0 volts.
The Camshaft Position Sensor (CMP) also provides
a signal to the Engine Control Module (ECM) at all
times when the engine is running. The ECM uses
this CMP information primarily on engine start-up.
Once the engine is running, the ECM uses the CMP
as a backup sensor for engine speed.
REMOVAL
(1) Raise and support vehicle
(2) Disconnect electrical connector at CKP sensor
(Fig. 12).
(3) Remove 1 sensor mounting bolt.
(4) Remove CKP sensor.
INSTALLATION
(1) Position and install CKP sensor to engine.
(2) Install 1 sensor mounting bolt and tighten to 9
N´m (80 in. lbs.) torque.(3) Install electrical connector to CKP sensor (Fig.
12).
Fig. 10 5.9L DIESEL CKP
1 - ENGINE HARMONIC BALANCER
2 - FRONT OF TIMING GEAR COVER
3 - CKP MOUNTING BOLT
4 - ELEC. CONNECTOR
5 - CKP SENSOR
6 - NOTCHES
Fig. 11 CKP NOTCHED TONEWHEEL
1 - ENGINE HARMONIC BALANCER
2 - NOTCHED TONEWHEEL
3 - FRONT OF CRANKSHAFT
Fig. 12 5.9L DIESEL CKP
1 - ENGINE HARMONIC BALANCER
2 - FRONT OF TIMING GEAR COVER
3 - CKP MOUNTING BOLT
4 - ELEC. CONNECTOR
5 - CKP SENSOR
6 - NOTCHES
DRFUEL INJECTION - DIESEL 14 - 73
CRANKSHAFT POSITION SENSOR (Continued)