1998 DODGE RAM 1500 Engine wiring

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)

(6) Install injector into cylinder head with male
connector port facing the intake manifold. Push down
on fuel injector mounting flange to engage o-ring and
seat injector.
(7) Tightening Sequence:
(a) Install fuel injector holdown clamp (mount-
ing flange) bolts.Do a preliminary tightening
of these bolts to 5 N´m (44 in. lbs.) torque.
This preliminary tightening insures the fuel
injector is seated and centered.
(b) After tightening, relieve bolt torque, but
leave both bolts threaded in place.
(c) Install high-pressure connector and retaining
nut. Do a preliminary tightening to 15 N´m (11 ft.
lbs.) torque.
(d) Alternately tighten injector holdown bolts to
10 N´m (89 in. lbs.) torque.
(e) Do a final tightening of the high-pressure
connector and retaining nut. Tighten to 50 N´m (37
ft. lbs.) torque.
(8) Connect injector solenoid wires and nuts to top
of injectors (Fig. 18). Tighten connector nuts to 1.25
N´m (11 in. lbs.) torque.Be very careful not to
overtighten these nuts as damage to fuel injec-
tor will occur.
(9) Install exhaust rocker arm assembly. Refer to
Engine.
(10) Set exhaust valve lash. Refer to Engine.
(11) Install high pressure fuel line. Refer to Torque
Specifications.Be sure to use a secondary
back-up wrench on the connector nut (fitting)
while torquing fuel line fitting.Refer to Fuel Line
Installation for additional information.
(12) Install valve cover. Refer to Engine.
(13) Install breather assembly.
(14) Connect negative battery cables to both bat-
teries.
FUEL INJECTOR RAIL
DESCRIPTION
The fuel injector rail is bolted to the top of the
intake manifold.
OPERATION
The fuel rail is used as a distribution device to
supply high-pressure fuel to the high-pressure fuel
lines.
REMOVAL
CAUTION: Cleanliness cannot be overemphasized
when handling or replacing diesel fuel system com-
ponents. This especially includes the fuel injectors,
high-pressure fuel lines and fuel injection pump.Very tight tolerances are used with these parts. Dirt
contamination could cause rapid part wear and pos-
sible plugging of fuel injector nozzle tip holes. This
in turn could lead to possible engine misfire.
Always wash/clean any fuel system component
thoroughly before disassembly and then air dry.
Cap or cover any open part after disassembly.
Before assembly, examine each part for dirt, grease
or other contaminants and clean if necessary. When
installing new parts, lubricate them with clean
engine oil or clean diesel fuel only.
(1) Disconnect both negative battery cables at both
batteries. Isolate ends of both cables.
(2) Disconnect electrical connector at fuel pressure
sensor.
(3) Remove banjo bolt at fuel limiting valve.
(4) Disconnect necessary wiring harness retention
clips from intake manifold.
(5) Lift 2 rubber covers to gain access to positive
(+), intake heater cable nuts. Remove 2 nuts and
remove 2 cables from studs.
(6) Carefully remove 4 high-pressure fuel lines
from top of injector rail engine. Note position of each
line while removing.Do not bend lines while
removing.
CAUTION: WHEN LOOSENING OR TIGHTENING
HIGH-PRESSURE LINES ATTACHED TO A SEPA-
RATE FITTING, USE A BACK-UP WRENCH ON FIT-
TING. DO NOT ALLOW FITTING TO ROTATE.
DAMAGE TO BOTH FUEL LINE AND FITTING WILL
RESULT.
(7) Carefully remove 2 high-pressure fuel lines at
each end of injector rail. Note position of each line
while removing.Do not bend lines while remov-
ing.
(8) Remove fuel line connecting injector pump to
fuel rail.
(9) Remove 3 injector rail mounting bolts (Fig. 22).
(10) Remove rail from top of intake manifold.
INSTALLATION
(1) Clean any dirt/debris from top of intake mani-
fold and bottom of fuel rail.
(2) Position fuel rail to top of manifold and install
3 mounting bolts. Refer to Torque Specifications.
(3) Install all high-pressure lines to rail. Refer to
Fuel Lines for procedures.
(4) Reposition wiring harness to intake manifold
and install new tie wraps.
(5) Install and tighten fuel limiting valve banjo
bolt. Refer to Torque Specifications.
(6) Connect electrical connector to fuel pressure
sensor.
(7) Position 2 positive (+) cables to intake heater
studs. Install 2 nuts.
14 - 78 FUEL INJECTION - DIESELDR
FUEL INJECTOR (Continued)

INTAKE AIR HEATER
DESCRIPTION
The intake manifold air heater element assembly
is located in the top of the intake manifold.
OPERATION
The air heater elements are used to heat incoming
air to the intake manifold. This is done to help
engine starting and improve driveability with cool or
cold outside temperatures.
Electrical supply for the 2 air heater elements is
controlled by the Engine Control Module (ECM)
through the 2 air heater relays. Refer to Intake Man-
ifold Air Heater Relays for more information.
Two heavy-duty cables connect the 2 air heater ele-
ments to the 2 air heater relays. Each of these cables
will supply approximately 95 amps at 12 volts to an
individual heating element within the heater block
assembly.
Refer to the Powertrain Diagnostic Procedures
manual for electrical operation and complete descrip-
tion of the intake heaters, including pre-heat and
post-heat cycles.
REMOVAL
If servicing either of the heater elements, the
entire block/element assembly must be replaced.
(1) Disconnect both negative battery cables at both
batteries. Cover and isolate ends of both cables.
(2) Remove both the intake manifold air intake
tube (above injection pump), and its rubber connector
hose (Fig. 26).
(3) Lift 2 rubber covers (Fig. 27) to gain access to 2
positive (+) cable nuts. Remove these 2 nuts (Fig. 28)
and remove 2 cables from studs.
(4) Disconnect ground strap (Fig. 27) at heater ele-
ment stud.
(5) Remove wiring harness clips.
(6) Remove engine oil dipstick tube bracket from
air inlet connection and fuel filter housing.
(7) Remove 4 housing mounting bolts (Fig. 27) and
remove heater element assembly.
INSTALLATION
If servicing either of the heater elements, the
entire block/element assembly must be replaced.
(1) Using 2 new gaskets, position element assem-
bly and air housing to intake manifold.
(2) Install ground cable to air housing.
(3) Install 4 housing bolts and tighten to 24 N´m
(18 ft. lbs.) torque.
(4) Connect 2 positive (+) heater cables at cable
mounting studs.Do not allow either of the cable
eyelets to contact any other metal source other
than the cable nuts/studs.
Fig. 24 INLET/PRESSURE SENSOR REMOVAL/
INSTALLATION
1 - INLET/PRESSURE SENSOR
2 - ELEC. CONNECTOR
3 - SENSOR MOUNTING SCREWS (2)
4 - TOP OF AIR FILTER COVER
Fig. 25 SENSOR O-RING
1 - IAT/PRESSURE SENSOR
2 - O-RING
14 - 80 FUEL INJECTION - DIESELDR
INLET AIR TEMPERATURE SENSOR/PRESSURE SENSOR (Continued)

INTAKE AIR HEATER RELAY
DESCRIPTION
The 2 intake manifold air heater relays are located
in the engine compartment. They are attached to a
common bracket. This bracket is attached to the
right battery tray (Fig. 29).
OPERATION
The Engine Control Module (ECM) operates the 2
heating elements through the 2 intake manifold air
heater relays.
Refer to Powertrain Diagnostic Procedures for an
electrical operation and complete description of the
intake heaters, including pre-heat and post-heat
cycles.
REMOVAL
The 2 intake manifold air heater relays are located
in the engine compartment. They are attached to a
common bracket. This bracket is attached to the
right battery tray (Fig. 29).
The mounting bracket and both relays are replaced
as an assembly.
(1) Disconnect both negative battery cables at both
batteries.
(2) Disconnect four relay trigger wires at both
relays. Note position of wiring before removing.
(3) Lift four rubber shields from all 4 cables.(4) Remove four nuts at cable connectors. Note
position of wiring before removing.
(5) Remove relay mounting bracket bolts and
remove relay assembly.
INSTALLATION
(1) Install relay assembly to battery tray. Tighten
mounting bolts to 4.5 N´m (40 in. lbs.) torque.
(2) Connect eight electrical connectors to relays.
(3) Connect battery cables to both batteries.
INTAKE AIR TEMPERATURE
SENSOR/MAP SENSOR
DESCRIPTION
The combination, dual function Intake Manifold
Air Temperature Sensor/MAP Sensor is installed into
the top of the intake manifold.
OPERATION
The combination, dual function Intake Manifold
Air Temperature Sensor/MAP Sensor is installed into
the top of the intake manifold with the sensor ele-
ment extending into the air stream.
The IAT portion of the sensor provides an input
voltage to the Engine Control Module (ECM) indicat-
ing intake manifold air temperature. The MAP por-
tion of the sensor provides an input voltage to the
ECM indicating turbocharger boost pressure.
REMOVAL
The combination, dual function Intake Manifold
Air Temperature Sensor/MAP (IAT/MAP) sensor is
installed into the top of the intake manifold (Fig. 30).
(1) Clean area around sensor.
(2) Disconnect electrical connector from IAT/MAP
sensor.
(3) Remove two T-15 Torx headed screws.
(4) Remove sensor from intake manifold.
(5) Check condition of sensor o-ring (Fig. 31).
INSTALLATION
(1) Check condition of sensor o-ring.
(2) Lubricate sensor o-ring with clean engine oil.
(3) Clean sensor mounting area at intake mani-
fold.
(4) Position sensor into intake manifold.
(5) Install and tighten 2 sensor mounting screws
to 1 N´m (9 in. lbs.) torque.
(6) Connect electrical connector to sensor.
Fig. 29 INTAKE MANIFOLD AIR HEATER RELAYS
1 - BATTERY
2 - CABLES TO INTAKE HEATERS
3 - RELAY TRIGGER WIRES
4 - INTAKE AIR HEATER RELAYS (2)
14 - 82 FUEL INJECTION - DIESELDR

CONDITION POSSIBLE CAUSES CORRECTION
NO 4-3 DOWNSHIFT
WHEN CONTROL SWITCH
IS TURNED OFF1. Control Switch Open/Shorted. 1. Test and replace switch if faulty.
2. Overdrive Solenoid Connector
Shorted.2. Test solenoids and replace if seized or
shorted.
3. PCM Malfunction. 3. Test with DRBTscan tool. Replace PCM
if faulty.
4. Valve Body Stuck Valves. 4. Repair stuck 3-4, lockup or lockup timing
valve.
CLUNK NOISE FROM
DRIVELINE ON CLOSED
THROTTLE 4-3
DOWNSHIFT1. Transmission Fluid Low. 1. Add Fluid.
2. Throttle Cable Mis-adjusted. 2. Adjust cable.
3. Overdrive Clutch Select Spacer
Wrong Spacer.3. Replace overdrive piston thrust plate
spacer.
3-4 UPSHIFT OCCURS
IMMEDIATELY AFTER 2-3
SHIFT1. Overdrive Solenoid Connector or
Wiring Shorted.1. Test connector and wiring for loose
connections, shorts or ground and repair as
needed.
2. TPS Malfunction. 2. Test TPS and replace as necessary.
Check with DRBTscan tool.
3. PCM Malfunction. 3. Test PCM with DRBTscan tool and
replace controller if faulty.
4. Overdrive Solenoid Malfunction. 4. Replace solenoid.
5. Valve Body Malfunction. 5. Remove, disassemble, clean and inspect
valve body components. Make sure all
valves and plugs slide freely in bores.
Polish valves with crocus cloth if needed.
WHINE/NOISE RELATED
TO ENGINE SPEED1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Shift Cable Incorrect Routing. 2. Check shift cable for correct routing.
Should not touch engine or bell housing.
DRAUTOMATIC TRANSMISSION - 48RE 21 - 153
AUTOMATIC TRANSMISSION - 48RE (Continued)

(28) Install the number 2 bearing onto the under-
drive hub with outer race against the hub with petro-
leum jelly.
(29) Install the underdrive hub into the input
clutch retainer.
(30) Install the number 3 bearing into the over-
drive hub with the outer race against the hub with
petroleum jelly.
(31) Install the overdrive hub into the input clutch
retainer.
(32) Install the number 4 bearing into the reverse
hub with outer race against the hub with petroleum
jelly.
(33) Install the reverse hub into the input clutch
retainer.
(34) Install the complete reverse clutch pack.
(35) Install the reverse reaction plate and snap-
ring.
(36) Push up on reaction plate to allow reverse
clutch to move freely.
INPUT SPEED SENSOR
DESCRIPTION
The Input and Output Speed Sensors are two-wire
magnetic pickup devices that generate AC signals as
rotation occurs. They are mounted in the left side of
the transmission case and are considered primary
inputs to the Transmission Control Module (TCM).
OPERATION
The Input Speed Sensor provides information on
how fast the input shaft is rotating. As the teeth of
the input clutch hub pass by the sensor coil, an AC
voltage is generated and sent to the TCM. The TCM
interprets this information as input shaft rpm.
The Output Speed Sensor generates an AC signal
in a similar fashion, though its coil is excited by rota-
tion of the rear planetary carrier lugs. The TCM
interprets this information as output shaft rpm.
The TCM compares the input and output speed
signals to determine the following:
²Transmission gear ratio
²Speed ratio error detection
²CVI calculation
The TCM also compares the input speed signal and
the engine speed signal to determine the following:
²Torque converter clutch slippage
²Torque converter element speed ratio
REMOVAL
(1) Raise vehicle.
(2) Place a suitable fluid catch pan under the
transmission.(3) Remove the wiring connector from the input
speed sensor (Fig. 91).
(4) Remove the bolt holding the input speed sensor
to the transmission case.
(5) Remove the input speed sensor from the trans-
mission case.
INSTALLATION
(1) Install the input speed sensor into the trans-
mission case.
(2) Install the bolt to hold the input speed sensor
into the transmission case. Tighten the bolt to 11.9
N´m (105 in.lbs.).
(3) Install the wiring connector onto the input
speed sensor
(4) Verify the transmission fluid level. Add fluid as
necessary.
(5) Lower vehicle.
LINE PRESSURE (LP) SENSOR
DESCRIPTION
The TCM utilizes a closed-loop system to control
transmission line pressure. The system contains a
variable force style solenoid, the Pressure Control
Solenoid, mounted on the side of the solenoid and
pressure switch assembly. The solenoid is duty cycle
controlled by the TCM to vent the unnecessary line
pressure supplied by the oil pump back to the sump.
The system also contains a variable pressure style
sensor, the Line Pressure Sensor, which is a direct
input to the TCM. The line pressure solenoid moni-
tors the transmission line pressure and completes the
Fig. 91 Input Speed Sensor
1 - OUTPUT SPEED SENSOR
2 - LINE PRESSURE SENSOR
3 - INPUT SPEED SENSOR
21 - 382 AUTOMATIC TRANSMISSION - 45RFE/545RFEDR
INPUT CLUTCH ASSEMBLY (Continued)

feedback loop to the TCM. The TCM uses this infor-
mation to adjust its control of the pressure control
solenoid to achieve the desired line pressure.
OPERATION
The TCM calculates the desired line pressure
based upon inputs from the transmission and engine.
The TCM calculates the torque input to the trans-
mission and uses that information as the primary
input to the calculation. The line pressure is set to a
predetermined value during shifts and when the
transmission is in the PARK and NEUTRAL posi-
tions. This is done to ensure consistent shift quality.
During all other operation, the actual line pressure is
compared to the desired line pressure and adjust-
ments are made to the pressure control solenoid duty
cycle.
REMOVAL
(1) Raise vehicle.
(2) Place a suitable fluid catch pan under the
transmission.
(3) Remove the wiring connector from the line
pressure sensor (Fig. 92).
(4) Remove the bolt holding the line pressure sen-
sor to the transmission case.
(5) Remove the line pressure sensor from the
transmission case.
INSTALLATION
(1) Install the line pressure sensor into the trans-
mission case.(2) Install the bolt to hold the line pressure sensor
into the transmission case. Tighten the bolt to 11.9
N´m (105 in.lbs.).
(3) Install the wiring connector onto the line pres-
sure sensor
(4) Verify the transmission fluid level. Add fluid as
necessary.
(5) Lower vehicle.
Fig. 92 Line Pressure Sensor
1 - OUTPUT SPEED SENSOR
2 - LINE PRESSURE SENSOR
3 - INPUT SPEED SENSOR
DRAUTOMATIC TRANSMISSION - 45RFE/545RFE 21 - 383
LINE PRESSURE (LP) SENSOR (Continued)