1998 DODGE RAM 1500 5.9l

CAMSHAFT POSITION SENSOR
DESCRIPTION
3.7L V-6
The Camshaft Position Sensor (CMP) on the 3.7L
6-cylinder engine is bolted to the right-front side of
the right cylinder head.
4.7L V-8
The Camshaft Position Sensor (CMP) on the 4.7L
V-8 engine is bolted to the right-front side of the
right cylinder head.
5.7L V-8
The Camshaft Position Sensor (CMP) on the 5.7L
V-8 engine is located below the generator on the tim-
ing chain / case cover on the right/front side of
engine.
5.9L Diesel
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
cover.
OPERATION
3.7L V-6
The Camshaft Position Sensor (CMP) sensor on the
3.7L V-6 engine contains a hall effect device referred
to as a sync signal generator. A rotating target wheel
(tonewheel) for the CMP is located at the front of the
camshaft for the right cylinder head (Fig. 6). This
sync signal generator detects notches located on a
tonewheel. As the tonewheel rotates, the notches
pass through the sync signal generator. The signal
from the CMP sensor is used in conjunction with the
Crankshaft Position Sensor (CKP) to differentiate
between fuel injection and spark events. It is also
used to synchronize the fuel injectors with their
respective cylinders.
When the leading edge of the tonewheel notch
enters the tip of the CMP, the interruption of mag-
netic field causes the voltage to switch high, result-
ing in a sync signal of approximately 5 volts.
When the trailing edge of the tonewheel notch
leaves then tip of the CMP, the change of the mag-
netic field causes the sync signal voltage to switch
low to 0 volts.
4.7L V-8
The CMP sensor on the 4.7L engine contains a hall
effect device called a sync signal generator to gener-
ate a fuel sync signal. This sync signal generator
detects notches located on a tonewheel. The tone-wheel is located at the front of the camshaft for the
right cylinder head (Fig. 7). As the tonewheel rotates,
the notches pass through the sync signal generator.
The pattern of the notches (viewed counter-clockwise
from front of engine) is: 1 notch, 2 notches, 3 notches,
3 notches, 2 notches 1 notch, 3 notches and 1 notch.
The signal from the CMP sensor is used in conjunc-
tion with the crankshaft position sensor to differenti-
ate between fuel injection and spark events. It is also
used to synchronize the fuel injectors with their
respective cylinders.
5.7L V-8
The CMP sensor is used in conjunction with the
crankshaft position sensor to differentiate between
fuel injection and spark events. It is also used to syn-
chronize the fuel injectors with their respective cylin-
ders. The sensor generates electrical pulses. These
pulses (signals) are sent to the Powertrain Control
Module (PCM). The PCM will then determine crank-
shaft position from both the camshaft position sensor
and crankshaft position sensor.
The tonewheel is located at the front of the cam-
shaft (Fig. 8). As the tonewheel rotates, notches (Fig.
8) pass through the sync signal generator.
When the cam gear is rotating, the sensor will
detect the notches. Input voltage from the sensor to
the PCM will then switch from a low (approximately
0.3 volts) to a high (approximately 5 volts). When the
sensor detects a notch has passed, the input voltage
switches back low to approximately 0.3 volts.
Fig. 6 CMP OPERATION- 3.7L V-6
1 - NOTCHES
2 - RIGHT CYLINDER HEAD
3 - CMP
4 - TONEWHEEL (TARGET WHEEL)
DRIGNITION CONTROL 8I - 7

5.9L Diesel
The Camshaft Position Sensor (CMP) contains a
hall effect device. A rotating target wheel (tonewheel)
for the CMP is located on the front timing gear. This
hall effect device detects notches located on the tone-
wheel. As the tonewheel rotates, the notches pass the
tip of the CMP.
When the leading edge of the tonewheel 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 tonewheel 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. 9) 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)
is the primary engine speed indicator for the engine
after the engine is running.
Fig. 7 CMP AND TONEWHEEL OPERATION - 4.7L
V-8
1 - NOTCHES
2 - RIGHT CYLINDER HEAD
3 - CAMSHAFT POSITION SENSOR
4 - TONEWHEEL
Fig. 8 CMP OPERATION - 5.7L ENGINE
1 - TIMING CHAIN COVER
2 - TONEWHEEL
3 - NOTCHES
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 COVER
8I - 8 IGNITION CONTROLDR
CAMSHAFT POSITION SENSOR (Continued)

5.9L Diesel
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
cover (Fig. 14).
(1) Disconnect electrical connector at CMP sensor
(Fig. 14).
(2) Remove sensor mounting bolt.
(3) Carefully twist sensor from timing gear cover.
(4) Check condition of sensor o-ring.
INSTALLATION
3.7L V-6
The Camshaft Position Sensor (CMP) on the 3.7L
V-6 engine is bolted to the front/top of the right cyl-
inder head (Fig. 10).
(1) Clean out machined hole in cylinder head.
(2) Apply a small amount of engine oil to sensor
o-ring.
(3) Install sensor into cylinder head with a slight
rocking and twisting action.
CAUTION: Before tightening sensor mounting bolt,
be sure sensor is completely flush to cylinder head.
If sensor is not flush, damage to sensor mounting
tang may result.
(4) Install mounting bolt and tighten. Refer to
torque specifications.(5) Connect electrical connector to sensor.
4.7L V-8
The Camshaft Position Sensor (CMP) on the 4.7L
V-8 engine is bolted to the front/top of the right cyl-
inder head (Fig. 11).
(1) Clean out machined hole in cylinder head.
(2) Apply a small amount of engine oil to sensor
o-ring.
(3) Install sensor into cylinder head 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 cylinder head.
If sensor is not flush, damage to sensor mounting
tang may result.
(4) Install mounting bolt and tighten. Refer to
Torque Specifications.
(5) Connect electrical connector to sensor.
5.7L V-8
The Camshaft Position Sensor (CMP) on the 5.7L
V-8 engine is bolted to the right / front side of the
timing chain cover (Fig. 12) or (Fig. 13).
(1) Clean out machined hole in cylinder head.
Fig. 13 CMP REMOVAL / INSTALLATION ± 5.7L V-8
1 - TIMING CHAIN COVER (RIGHT/FRONT)
2 - CMP SENSOR
3 - MOUNTING BOLT
Fig. 14 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 COVER
8I - 10 IGNITION CONTROLDR
CAMSHAFT POSITION SENSOR (Continued)

(2) Apply a small amount of engine oil to sensor
o-ring.
(3) Install sensor into cylinder head 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 timing chain
cover. If sensor is not flush, damage to sensor
mounting tang may result.
(4) Install mounting bolt and tighten. Refer to
Torque Specifications.
(5) Connect electrical connector to sensor.
5.9L Diesel
The CMP is located on the back of the timing gear
cover (Fig. 14).
(1) Clean out machined hole in back of timing gear
cover.
(2) Apply a small amount of engine oil to sensor
o-ring.
(3) Install sensor into timing gear cover with a
slight rocking action. Do not twist sensor into posi-
tion as damage to o-ring may result.
CAUTION: Before tightening sensor mounting bolt,
be sure sensor is completely flush to back of timing
chain cover. If sensor is not flush, damage to sen-
sor mounting tang may result.
(4) Install mounting bolt and tighten. Refer to
Torque Specifications.
(5) Connect electrical connector to sensor.
IGNITION COIL
DESCRIPTION
3.7L V-6
The 3.7L V-6 engine uses 6 dedicated, and individ-
ually fired coil for each spark plug (Fig. 15). Each
coil is mounted directly into the cylinder head and
onto the top of each spark plug (Fig. 16).
4.7L V-8
The 4.7L V±8 engine uses 8 dedicated, and individ-
ually fired coil (Fig. 15) for each spark plug. Each
coil is mounted directly to the top of each spark plug
(Fig. 17).
5.7L V-8
The 5.7L V±8 engine uses 8 dedicated, and individ-
ually fired coil (Fig. 18) for each pair of spark plugs.
Each coil is mounted directly to the top of each spark
plug (Fig. 19). Each coil is bolted to the valve cover.
Fig. 15 IGNITION COIL - 3.7L V-6/ 4.7L V-8
1 - O-RING
2 - IGNITION COIL
3 - ELECTRICAL CONNECTOR
Fig. 16 IGNITION COIL LOCATION - 3.7L V-6
1 - IGNITION COIL
2 - COIL MOUNTING NUT
DRIGNITION CONTROL 8I - 11
CAMSHAFT POSITION SENSOR (Continued)

5.9L Diesel With Manual Trans.
The speed control system is fully electronically con-
trolled by the Engine Control Module (ECM).A
cable and a vacuum controlled servo are not
used if the vehicle is equipped with a manual
transmission and a diesel engine. This is a ser-
vo-less system.The controls consist of two steering
wheel mounted switches. The switches are labeled:
ON/OFF, RES/ACCEL, SET, COAST, and CANCEL.
The system is designed to operate at speeds above
30 mph (50 km/h).
WARNING: THE USE OF SPEED CONTROL IS NOT
RECOMMENDED WHEN DRIVING CONDITIONS DO
NOT PERMIT MAINTAINING A CONSTANT SPEED,
SUCH AS IN HEAVY TRAFFIC OR ON ROADS THAT
ARE WINDING, ICY, SNOW COVERED, OR SLIP-
PERY.
OPERATION
When speed control is selected by depressing the
ON switch, the PCM (the ECM with a diesel engine)
allows a set speed to be stored in its RAM for speed
control. To store a set speed, depress the SET switch
while the vehicle is moving at a speed between 35
and 85 mph. In order for the speed control to engage,
the brakes cannot be applied, nor can the gear selec-
tor be indicating the transmission is in Park or Neu-
tral.
The speed control can be disengaged manually by:
²Stepping on the brake pedal
²Depressing the OFF switch
²Depressing the CANCEL switch.
²Depressing the clutch pedal (if equipped).
NOTE: Depressing the OFF switch or turning off the
ignition switch will erase the set speed stored in
the PCM (the ECM with a diesel engine).
For added safety, the speed control system is pro-
grammed to disengage for any of the following condi-
tions:
²An indication of Park or Neutral
²A rapid increase rpm (indicates that the clutch
has been disengaged)
²Excessive engine rpm (indicates that the trans-
mission may be in a low gear)
²The speed signal increases at a rate of 10 mph
per second (indicates that the coefficient of friction
between the road surface and tires is extremely low)
²The speed signal decreases at a rate of 10 mph
per second (indicates that the vehicle may have
decelerated at an extremely high rate)Once the speed control has been disengaged,
depressing the RES/ACCEL switch (when speed is
greater than 30 mph) restores the vehicle to the tar-
get speed that was stored in the PCM (the ECM with
a diesel engine).
While the speed control is engaged, the driver can
increase the vehicle speed by depressing the RES/AC-
CEL switch. The new target speed is stored in the
PCM (the ECM with a diesel engine) when the RES/
ACCEL is released. The PCM (the ECM with a diesel
engine) also has a9tap-up9feature in which vehicle
speed increases at a rate of approximately 2 mph for
each momentary switch activation of the RES/AC-
CEL switch.
A ªtap downº feature is used to decelerate without
disengaging the speed control system. To decelerate
from an existing recorded target speed, momentarily
depress the COAST switch. For each switch activa-
tion, speed will be lowered approximately 1 mph.DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - VACUUM SUPPLY
TEST
3.7L / 4.7L Gas Powered Engines
3.7L/4.7L gas powered engines: actual engine vac-
uum, a vacuum reservoir, a one-way check valve and
vacuum lines are used to supply vacuum to the speed
control servo.
(1) Disconnect vacuum hose at speed control servo
and install a vacuum gauge into the disconnected
hose.
(2) Start engine and observe gauge at idle. Vac-
uum gauge should read at least ten inches of mer-
cury.
(3) If vacuum is less than ten inches of mercury,
determine source of leak. Check vacuum line to
engine for leaks. Also check actual engine intake
manifold vacuum. If manifold vacuum does not meet
this requirement, check for poor engine performance
and repair as necessary.
(4) If vacuum line to engine is not leaking, check
for leak at vacuum reservoir. To locate and gain
access to reservoir, refer to Vacuum Reservoir Remov-
al/Installation in this group. Disconnect vacuum line
at reservoir and connect a hand-operated vacuum
pump to reservoir fitting. Apply vacuum. Reservoir
vacuum should not bleed off. If vacuum is being lost,
replace reservoir.
8P - 2 SPEED CONTROLDR
SPEED CONTROL (Continued)

(5) Verify operation of one-way check valve and
check it for leaks.
(a) Locate one-way check valve. The valve is
located in vacuum line between vacuum reservoir
and engine vacuum source. Disconnect vacuum
hoses (lines) at each end of valve.
(b) Connect a hand-operated vacuum pump to
reservoir end of check valve. Apply vacuum. Vac-
uum should not bleed off. If vacuum is being lost,
replace one-way check valve.
(c) Connect a hand-operated vacuum pump to
vacuum source end of check valve. Apply vacuum.
Vacuum should flow through valve. If vacuum is
not flowing, replace one-way check valve. Seal the
fitting at opposite end of valve with a finger and
apply vacuum. If vacuum will not hold, diaphragm
within check valve has ruptured. Replace valve.
5.7 Gas
Vacuum is not used for any part of the speed con-
trol system if equipped with a 5.7L V-8 engine.
5.9L Diesel Engine With Manual Trans.
Vacuum is not used for any part of the speed con-
trol system if equipped with a diesel engine and a
manual transmission.
5.9L Diesel Engines With Automatic Trans.
If equipped with a diesel powered engine and an
automatic transmission, an electric vacuum pump
and vacuum lines are used to supply vacuum to the
speed control servo. A vacuum reservoir is not used.
DIAGNOSIS AND TESTING - ROAD TEST
Perform a vehicle road test to verify reports of
speed control system malfunction. The road test
should include attention to the speedometer. Speed-ometer operation should be smooth and without flut-
ter at all speeds.
Flutter in the speedometer indicates a problem
which might cause surging in the speed control sys-
tem. The cause of any speedometer problems should
be corrected before proceeding. Refer to Instrument
Cluster for speedometer diagnosis.
If a road test verifies a system problem and the
speedometer operates properly, check for:
²A Diagnostic Trouble Code (DTC). If a DTC
exists, conduct tests per the Powertrain Diagnostic
Procedures service manual.
²A misadjusted brake (stop) lamp switch. This
could also cause an intermittent problem.
²Loose, damaged or corroded electrical connec-
tions at the servo (if used). Corrosion should be
removed from electrical terminals and a light coating
of Mopar MultiPurpose Grease, or equivalent,
applied.
²Leaking vacuum reservoir (if used).
²Loose or leaking vacuum hoses or connections (if
used).
²Defective one-way vacuum check valve (if used).
²Secure attachment of both ends of the speed con-
trol servo cable (if used).
²Smooth operation of throttle linkage (if used)
and throttle body air valve.
²Failed speed control servo (if used). Do the servo
vacuum test.
CAUTION: When test probing for voltage or conti-
nuity at electrical connectors, care must be taken
not to damage connector, terminals or seals. If
these components are damaged, intermittent or
complete system failure may occur.
SPECIFICATIONS
TORQUE - SPEED CONTROL
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Servo Mounting Bracket-
to-Servo Nuts7-60
Servo Mounting Bracket-
to-Battery Tray Screws4-30
Speed Control Switch
Mounting Screws1.7 - 15
Vacuum Reservoir
Mounting Nuts3-20
DRSPEED CONTROL 8P - 3
SPEED CONTROL (Continued)

CABLE
DESCRIPTION
The speed control servo cable is connected between
the speed control vacuum servo diaphragm and the
throttle body control linkage. This cable is used with
3.7L/4.7L gas powered engines only. It is also used if
equipped with a 5.9L diesel engine equipped with an
automatic transmission.
A speed control servo cableis not usedif equipped
with either a 5.9L diesel engine equipped with a
manual transmission, or any 5.7L engine/transmis-
sion combinations.
OPERATION
This cable causes the throttle control linkage to
open or close the throttle valve in response to move-
ment of the vacuum servo diaphragm.
REMOVAL
3.7L / 4.7L GAS
(1) Disconnect negative battery cable at battery.
(2) Remove air intake tube at top of throttle body.
The accelerator cable must be partially removed to
gain access to speed control cable.
(3) Hold throttle in wide open position. While held
in this position, slide throttle cable pin (Fig. 1) from
throttle body bellcrank.
(4) Using a pick or small screwdriver, press release
tab (Fig. 2) 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. 2)
towards right side of vehicle to remove throttle cable
from throttle body bracket.
(5) Using finger pressure only, disconnect servo
cable connector (Fig. 3) at throttle body bellcrank pin
by pushing connector off bellcrank pin towards front
of vehicle.DO NOT try to pull connector off per-
pendicular to the bellcrank pin. Connector will
be broken.
(6) Slide speed control cable plastic mount towards
right of vehicle to remove cable from throttle body
bracket (Fig. 4).
(7) Remove servo cable from servo. Refer to Servo
Removal/Installation.
5.9L Diesel Ð Auto. Trans.
(1) Disconnect both negative battery cables at both
batteries.
(2) Remove cable/lever/linkage cover. Refer to
Speed Control Servo Removal/Installation.
(3) Remove (disconnect) servo cable from servo.
Refer to Speed Control Servo Removal/Installation.(4) Using finger pressure only, disconnect end of
servo cable from throttle lever pin by pulling forward
on connector while holding lever rearward (Fig. 5).
DO NOT try to pull connector off perpendicular
to lever pin. Connector will be broken.
(5) Squeeze 2 pinch tabs (Fig. 5) on sides of speed
control cable at mounting bracket and push cable
rearward out of bracket.
Fig. 1 THROTTLE CABLE PIN - 3.7L / 4.7L
1 - THROTTLE CABLE PIN
2 - THROTTLE BODY BELLCRANK
3 - PUSH UP HERE
Fig. 2 THROTTLE CABLE RELEASE TAB - 3.7L /
4.7L
1 - THROTTLE CABLE
2 - RELEASE TAB
3 - PICK OR SCREWDRIVER
4 - PLASTIC CABLE MOUNT
8P - 4 SPEED CONTROLDR

(6) Remove cable from vehicle.
INSTALLATION
3.7L / 4.7L Gas
(1) Install end of cable to speed control servo.
Refer to Servo Removal/Installation.(2) Slide speed control cable plastic mount into
throttle body bracket.
(3) Install speed control cable connector onto throt-
tle body bellcrank pin (push rearward to snap into
location).
(4) Slide throttle (accelerator) cable plastic mount
into throttle body bracket. Continue sliding until
cable release tab is aligned to hole in throttle body
mounting bracket.
(5) While holding throttle to wide open position,
place throttle cable pin into throttle body bellcrank.
(6) Install air intake tube to top of throttle body.
(7) Connect negative battery cable at battery.
(8) Before starting engine, operate accelerator
pedal to check for any binding.
5.9L Diesel Ð Auto. Trans.
(1) Install (connect) end of speed control servo
cable to speed control servo. Refer to Speed Control
Servo Removal/Installation.
(2) Install cable through mounting hole on mount-
ing bracket. Cable snaps into bracket.
(3) Connect servo cable to throttle lever by push-
ing cable connector rearward onto lever pin while
holding lever forward.
(4) Connect negative battery cables to both batter-
ies.
Fig. 3 SPEED CONTROL CABLE AT BELLCRANK -
3.7L / 4.7L
1 - THROTTLE BODY BELLCRANK
2 - SPEED CONTROL CABLE CONNECTOR
Fig. 4 SPEED CONTROL CABLE AT BRACKET - 3.7L
/ 4.7L
1 - THROTTLE CABLE BRACKET
2 - PLASTIC CABLE MOUNT
3 - SPEED CONTROL CABLE
Fig. 5 SERVO CABLE AT THROTTLE LEVER Ð 5.9L
DIESEL
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
DRSPEED CONTROL 8P - 5
CABLE (Continued)