1998 DODGE RAM 1500 Throttle

FUEL INJECTION - DIESEL
TABLE OF CONTENTS
page page
ACCELERATOR PEDAL POSITION SENSOR
DESCRIPTION.........................68
OPERATION...........................68
REMOVAL.............................68
INSTALLATION.........................71
CAMSHAFT POSITION SENSOR
DESCRIPTION.........................71
OPERATION...........................71
REMOVAL.............................72
INSTALLATION.........................72
CRANKSHAFT POSITION SENSOR
DESCRIPTION.........................72
OPERATION...........................72
REMOVAL.............................73
INSTALLATION.........................73
FUEL CONTROL ACTUATOR
DESCRIPTION.........................74
OPERATION...........................74
REMOVAL.............................74
FUEL INJECTOR
DESCRIPTION.........................74
OPERATION...........................74
REMOVAL.............................75
INSTALLATION.........................77
FUEL INJECTOR RAIL
DESCRIPTION.........................78
OPERATION...........................78
REMOVAL.............................78
INSTALLATION.........................78INLET AIR TEMPERATURE SENSOR/
PRESSURE SENSOR
DESCRIPTION.........................79
OPERATION...........................79
REMOVAL.............................79
INSTALLATION.........................79
INTAKE AIR HEATER
DESCRIPTION.........................80
OPERATION...........................80
REMOVAL.............................80
INSTALLATION.........................80
INTAKE AIR HEATER RELAY
DESCRIPTION.........................82
OPERATION...........................82
REMOVAL.............................82
INSTALLATION.........................82
INTAKE AIR TEMPERATURE SENSOR/MAP
SENSOR
DESCRIPTION.........................82
OPERATION...........................82
REMOVAL.............................82
INSTALLATION.........................82
MAP SENSOR
DESCRIPTION.........................83
THROTTLE CONTROL CABLE
REMOVAL.............................83
INSTALLATION.........................84
PTO SWITCH
DESCRIPTION.........................85
OPERATION...........................85
ACCELERATOR PEDAL
POSITION SENSOR
DESCRIPTION
Engine Mounted Sensor:The APPS assembly is
located at the top-left-front of the engine. A plastic
cover is used to cover the assembly. The actual sen-
sor is located behind its mounting bracket.
Battery Tray Mounted Sensor:The Accelerator
Pedal Position Sensor (APPS) assembly is located
under the vehicle battery tray. A cable connects the
assembly to the accelerator pedal. A plastic cover
with a movable door is used to cover the assembly.
OPERATION
Engine Mounted Sensor:The Accelerator Pedal
Position Sensor (APPS) is a linear potentiometer. Itprovides the Engine Control Module (ECM) with a
DC voltage signal proportional to the angle, or posi-
tion of the accelerator pedal.
Battery Tray Mounted Sensor:The APPS pro-
vides the ECM with two DC voltage signals which
change as the position of the accelerator changes.
One of the DC voltage signals will be half the voltage
of the other signal.
REMOVAL
Engine Mounted Sensor :
The APPS is serviced (replaced) as one assembly
including the lever, brackets and sensor. The APPS is
calibrated to its mounting bracket. The APPS assem-
bly is located at left-front of engine below plastic
cable/lever/linkage cover (Fig. 1).
14 - 68 FUEL INJECTION - DIESELDR

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)

INSTALLATION
Engine Mounted Sensor :
The APPS is serviced (replaced) as one assembly
including the lever, brackets and sensor. The APPS is
calibrated to its mounting bracket.
(1) Snap electrical connector into bottom of sensor.
(2) Position APPS assembly to engine and install 6
bolts. Tighten bolts to 24 N´m (18 ft. lbs.) torque.
(3) Connect wiring harness clip at bottom of
bracket.
(4) Refer to Group 21, Transmission for transmis-
sion control cable installation procedures.
(5) Install speed control cable into mounting
bracket. Be sure pinch tabs have secured cable.
(6) Install throttle cable into mounting bracket. Be
sure pinch tabs have secured cable.
(7) Connect throttle cable at lever (snaps on).
(8) Connect speed control cable to lever by pushing
cable connector rearward onto lever pin while hold-
ing lever forward.
(9) Install cable cover.
(10) Connect both negative battery cables to both
batteries.
(11) If necessary, use DRB IIItScan Tool to erase
any Diagnostic Trouble Codes (DTC's) from ECM.Battery Tray Mounted Sensor :
(1) Install Accelerator Pedal Position Sensor
(APPS) cable to accelerator pedal. Refer to Accelera-
tor Pedal Removal / Installation.
(2) Connect electrical connector to APPS.
(3) If necessary, connect cable to APPS lever ball
socket (snaps on).
(4) Snap APPS cable cover closed.
(5) Position APPS assembly to bottom of battery
tray and install 3 bolts. Refer to Torque Specifica-
tions.
(6) Install wheelhouse liner. Refer to Body.
(7) Perform the following procedure:
(a) Connect negative battery cables to both bat-
teries.
(b) Turn key switch ON, but do not crank
engine.
(c) Leave key switch ON for a minimum of 10
seconds. This will allow ECM to learn electrical
parameters.
(8) If necessary, use DRB IIItScan Tool to erase
any Diagnostic Trouble Codes (DTC's) from ECM.
CAMSHAFT POSITION
SENSOR
DESCRIPTION
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.
OPERATION
The diesel Camshaft Position Sensor (CMP) con-
tains a hall effect device. A rotating target wheel
(tonewheel) for the CMP is located on the camshaft
gear. This hall effect device detects notches located
on the back side of the camshaft gear. As the cam-
shaft gear rotates, the notches pass the tip of the
CMP.
When the leading edge of the notch passes the tip
of the CMP, 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 notch passes the tip
of the CMP, the following occurs: The change of the
magnetic field causes the signal voltage to switch low
to 0 volts.
The CMP (Fig. 8) provides a signal to the Engine
Control Module (ECM) at all times when the engine
is running. The ECM uses the CMP information pri-
marily on engine start-up. Once the engine is run-
ning, the ECM uses the CMP as a backup sensor for
engine speed. The Crankshaft Position Sensor (CKP)
Fig. 7 APPS CABLE (OFF ENGINE MOUNTING)
1 - APPS LEVER
2 - BALL SOCKET
3 - SWING-DOWN DOOR
4 - CABLE CLIP
5 - CABLE
DRFUEL INJECTION - DIESEL 14 - 71
ACCELERATOR PEDAL POSITION SENSOR (Continued)

MAP SENSOR
DESCRIPTION
A combination, dual function Intake Manifold Air
Temperature Sensor/MAP Sensor is used. Refer to
Intake Air Temperature Sensor/MAP Sensor for infor-
mation.
THROTTLE CONTROL CABLE
REMOVAL
If Equipped With Engine Mounted Accelerator Pedal
Position Sensor
(1) Disconnect both negative battery cables at both
batteries.
(2) From inside vehicle, hold up accelerator pedal.
Remove plastic cable retainer and throttle cable core
wire from upper end of pedal arm (Fig. 32). The plas-
tic cable retainer snaps into pedal arm.
(3) From inside vehicle, remove cable clip (Fig. 32).
(4) Remove cable core wire at pedal arm.
(5) Remove cable housing from dash panel and
pull cable into engine compartment.
(6) Remove cable cover (Fig. 33). Cable cover is
attached with 2 Phillips screws, 2 plastic retention
clips and 2 push tabs (Fig. 33). 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.
(7) Using 2 screwdrivers, pry cable connector
socket from throttle lever ball (Fig. 34).Be very
careful not to bend throttle lever arm.
If Equipped With Battery Tray Mounted Accelerator Pedal
Position Sensor
The Throttle Control Cable connects the accelera-
tor 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) Disconnect both negative battery cables at both
batteries.
(2) From inside vehicle, hold up accelerator pedal.
Remove plastic cable retainer and throttle cable core
wire from upper end of pedal arm (Fig. 35). The plas-
tic cable retainer snaps into pedal arm.
(3) Remove cable core wire at pedal arm.
(4) Remove APPS. Refer to (Diesel) Accelerator
Pedal Position Sensor (APPS) Removal / Installation.
(5) From inside vehicle, remove cable clip (Fig. 35).
Fig. 30 INTAKE/MAP SENSOR
1 - TOP OF INTAKE MANIFOLD
2 - IAT/MAP SENSOR
3 - ELEC. CONNECTOR
4 - MOUNTING BOLTS (2)
Fig. 31 SENSOR O-RING
1 - IAT/MAP SENSOR
2 - O-RING
DRFUEL INJECTION - DIESEL 14 - 83
INTAKE AIR TEMPERATURE SENSOR/MAP SENSOR (Continued)

(6) Remove cable housing from dash panel and
pull cable into engine compartment.
(7) Remove cable housing at APPS bracket by
pressing on release tab with a small screwdriver.Toprevent cable housing breakage, press on tab
only enough to release cable from APPS
bracket.
INSTALLATION
Accelerator Pedal Position Sensor Mounted To Engine
(1) Install cable through mounting hole on cable
mounting bracket (Fig. 34). Cable snaps into bracket.
Be sure 2 pinch tabs are secure.
(2) Using large pliers, connect cable end socket to
throttle lever ball (snaps on).
(3) Install remaining cable housing end into and
through dash panel opening (snaps into position).
The two plastic pinch tabs should lock cable to dash
panel.
(4) From inside vehicle, hold up accelerator pedal.
Install throttle cable core wire and plastic cable
retainer into and through upper end of pedal arm
(the plastic retainer is snapped into pedal arm).
When installing plastic retainer to accelerator pedal
arm, note index tab on pedal arm (Fig. 32). Align
index slot on plastic cable retainer to this index tab.
(5) Connect negative battery cables to both batter-
ies.
(6) Before starting engine, operate accelerator
pedal to check for any binding.
(7) Install cable/lever cover.
Fig. 32 ACCELERATOR PEDAL MOUNTING
1 - ACCELERATOR CABLE
2 - PLASTIC RETAINER (CLIP)
3 - THROTTLE PEDAL ARM
4 - PEDAL / BRACKET ASSEMBLY
5 - CABLE CLIP
Fig. 33 CABLE/LEVER/THROTTLE LINKAGE COVER
1 - CABLE/LEVER/LINKAGE COVER
2 - PUSH UP LOWER TAB
3 - SCREWS/CLIPS (2)
4 - TAB PUSH HERE
Fig. 34 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
14 - 84 FUEL INJECTION - DIESELDR
THROTTLE CONTROL CABLE (Continued)

Accelerator Pedal Position Sensor Not Mounted To Engine
(1) Attach cable to Accelerator Pedal Position Sen-
sor (APPS). Refer to APPS (Diesel) Removal / Instal-
lation.
(2) Push cable housing into rubber grommet and
through opening in dash panel.
(3) From inside vehicle, install clip holding cable
to dashpanel (Fig. 35).
(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
Engine Control Module (ECM).
PTO SWITCH
DESCRIPTION
This Engine Control Module (ECM) input is used
only on models equipped with aftermarket Power
Take Off (PTO) units.
OPERATION
This input is used only to tell the PCM (non-die-
sel), or ECM (diesel) that the aftermarket PTO
(Power Take Off) unit has been engaged. The PCM
(or ECM) will disable (temporarily shut down) cer-
tain OBD II diagnostic trouble codes when the PTO
unit is engaged.
Fig. 35 ACCELERATOR PEDAL MOUNTING
1 - ACCELERATOR CABLE
2 - PLASTIC RETAINER (CLIP)
3 - THROTTLE PEDAL ARM
4 - PEDAL / BRACKET ASSEMBLY
5 - CABLE CLIP
DRFUEL INJECTION - DIESEL 14 - 85
THROTTLE CONTROL CABLE (Continued)

OUTPUT SHAFT FRONT BEARING
REMOVAL............................216
INSTALLATION........................216
OUTPUT SHAFT REAR BEARING
REMOVAL............................216
INSTALLATION........................217
OVERDRIVE CLUTCH
DESCRIPTION........................217
OPERATION..........................217
OVERDRIVE UNIT
REMOVAL............................218
DISASSEMBLY........................218
CLEANING...........................225
INSPECTION.........................225
ASSEMBLY...........................226
INSTALLATION........................235
OVERRUNNING CLUTCH CAM/OVERDRIVE
PISTON RETAINER
DESCRIPTION........................236
OPERATION..........................236
DISASSEMBLY........................236
CLEANING...........................236
INSPECTION.........................237
ASSEMBLY...........................237
PISTONS
DESCRIPTION........................239
OPERATION..........................239
PLANETARY GEARTRAIN/OUTPUT SHAFT
DESCRIPTION........................241
OPERATION..........................241
DISASSEMBLY........................242
INSPECTION.........................243
ASSEMBLY...........................244
REAR CLUTCH
DESCRIPTION........................247
OPERATION..........................248
DISASSEMBLY........................248
CLEANING...........................248
INSPECTION.........................248
ASSEMBLY...........................249
REAR SERVO
DESCRIPTION........................251
OPERATION..........................251
DISASSEMBLY........................251
CLEANING...........................251
ASSEMBLY...........................251
SHIFT MECHANISM
DESCRIPTION........................252OPERATION..........................252
SOLENOID
DESCRIPTION........................252
OPERATION..........................252
SPEED SENSOR
DESCRIPTION........................253
OPERATION..........................253
THROTTLE VALVE CABLE
DESCRIPTION........................253
ADJUSTMENTS - THROTTLE VALVE CABLE . 254
TORQUE CONVERTER
DESCRIPTION........................255
OPERATION..........................259
REMOVAL............................260
INSTALLATION........................260
TORQUE CONVERTER DRAINBACK VALVE
DESCRIPTION........................261
OPERATION..........................261
STANDARD PROCEDURE - TORQUE
CONVERTER DRAINBACK VALVE........261
TOW/HAUL OVERDRIVE SWITCH
DESCRIPTION........................261
OPERATION..........................262
DIAGNOSIS AND TESTING - OVERDRIVE
ELECTRICAL CONTROLS..............262
REMOVAL............................262
INSTALLATION........................262
TRANSMISSION RANGE SENSOR
DESCRIPTION........................263
OPERATION..........................263
DIAGNOSIS AND TESTING - TRANSMISSION
RANGE SENSOR (TRS)................264
REMOVAL............................265
INSTALLATION........................266
TRANSMISSION TEMPERATURE SENSOR
DESCRIPTION........................267
OPERATION..........................267
VALVE BODY
DESCRIPTION........................267
OPERATION..........................272
REMOVAL............................286
DISASSEMBLY........................287
CLEANING...........................298
INSPECTION.........................298
ASSEMBLY...........................299
INSTALLATION........................309
ADJUSTMENTS - VALVE BODY...........310
DRAUTOMATIC TRANSMISSION - 48RE 21 - 131

IDENTIFICATION
Transmission identification numbers are stamped
on the left side of the case just above the oil pan gas-
ket surface (Fig. 2). Refer to this information when
ordering replacement parts.
GEAR RATIOS
The 48RE gear ratios are:
1st.................................2.45:1
2nd................................1.45:1
3rd................................1.00:1
4th.................................0.69:1
Rev.................................2.20:1
OPERATION
The application of each driving or holding compo-
nent is controlled by the valve body based upon the
manual lever position, throttle pressure, and gover-
nor pressure. The governor pressure is a variable
pressure input to the valve body and is one of the
signals that a shift is necessary. First through fourth
gear are obtained by selectively applying and releas-
ing the different clutches and bands. Engine power is
thereby routed to the various planetary gear assem-
blies which combine with the overrunning clutch
assemblies to generate the different gear ratios. The
torque converter clutch is hydraulically applied and
is released when fluid is vented from the hydraulic
circuit by the torque converter control (TCC) solenoid
on the valve body. The torque converter clutch is con-
trolled by the Powertrain Control Module (PCM). The
torque converter clutch engages in fourth gear, and
in third gear under various conditions, such as when
the O/D switch is OFF, when the vehicle is cruising
on a level surface after the vehicle has warmed up.
The torque converter clutch can also be engaged in
the MANUAL SECOND gear position if high trans-
mission temperatures are sensed by the PCM. The
torque converter clutch will disengage momentarily
when an increase in engine load is sensed by the
PCM, such as when the vehicle begins to go uphill or
the throttle pressure is increased. The torque con-
verter clutch feature increases fuel economy and
reduces the transmission fluid temperature.
Since the overdrive clutch is applied in fourth gear
only and the direct clutch is applied in all ranges
except fourth gear, the transmission operation for
park, neutral, and first through third gear will be
described first. Once these powerflows are described,
the third to fourth shift sequence will be described.
1 - TORQUE CONVERTER 10 - OVERDRIVE CLUTCH
2 - INPUT SHAFT 11 - DIRECT CLUTCH
3 - OIL PUMP 12 - PLANETARY GEAR
4 - FRONT BAND 13 - INTERMEDIATE SHAFT
5 - FRONT CLUTCH 14 - OVERDRIVE OVERRUNNING CLUTCH
6 - REAR CLUTCH 15 - DIRECT CLUTCH SPRING
7 - PLANETARIES 16 - OVERDRIVE PISTON RETAINER
8 - REAR BAND 17 - OIL PAN
9 - OVERRUNNING CLUTCH 18 - VALVE BODY
Fig. 2 Transmission Part Number And Serial
Number Location
1 - PART NUMBER
2 - BUILD DATE
3 - SERIAL NUMBER
21 - 134 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)