2002 DODGE RAM injector

(11) Inspect accelerator cable, transmission throt-
tle cable (if equipped) and cruise control cable con-
nections (if equipped). Check their connections to the
throttle arm of throttle body for any binding or
restrictions.
(12) If equipped with vacuum brake booster, verify
that vacuum booster hose is firmly connected to fit-
ting on intake manifold. Also check connection to
brake vacuum booster.
(13) Inspect the air cleaner inlet and air cleaner
element for dirt or restrictions.
(14) Inspect radiator grille area, radiator fins and
air conditioning condenser for restrictions.
(15) Verify that the intake manifold air tempera-
ture sensor wire connector is firmly connected to har-
ness connector (Fig. 15).(16) Verify that MAP sensor electrical connector is
firmly connected to MAP sensor (Fig. 16).
(17) Verify that fuel injector wire harness connec-
tors are firmly connected to injectors in the correct
order. Each harness connector is numerically tagged
with the injector number (INJ 1, INJ 2 etc.) of its
corresponding fuel injector and cylinder number.
(18) Verify harness connectors are firmly con-
nected to idle air control (IAC) motor and throttle
position sensor (TPS).
(19) Verify that wire harness connector is firmly
connected to the engine coolant temperature sensor
(Fig. 17).
Fig. 14 Ignition Coil PackÐ8.0L Engine
Fig. 15 Air Temperature SensorÐ8.0L Engine
1 - INTAKE MANIFOLD AIR TEMP. SENSOR
2 - INTAKE MANIFOLD
Fig. 16 Map Sensor Ð8.0L Engine
1 - MAP SENSOR
2 - MOUNTING BOLTS
3 - THROTTLE BODY
Fig. 17 Engine Coolant Temperature SensorÐ8.0L
Engine
1 - ENGINE COOLANT TEMP. SENSOR
2 - THERMOSTAT HOUSING
3 - GENERATOR
BR/BEFUEL INJECTION - GASOLINE 14 - 33
FUEL INJECTION - GASOLINE (Continued)

INSTALLATION
(1) Position pedal/bracket assembly over pivot pin
(Fig. 22) .
(2) Install two new pivots/bushings. Using large
pliers, press both bushings together until they bot-
tom on sides of pedal/bracket assembly. Bushing
retaining ears will snap into position when properly
installed.
(3) 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. 21) . Align
index slot on plastic cable retainer to this index tab.
CRANKSHAFT POSITION
SENSOR
DESCRIPTION
DESCRIPTION - 5.9L
The Crankshaft Position (CKP) sensor is located
near the outer edge of the flywheel (starter ringear).
DESCRIPTION - 8.0L
The Crankshaft Position (CKP) sensor is located on
the right-lower side of the cylinder block, forward of
the right engine mount, just above the oil pan rail
(Fig. 23).
OPERATION
OPERATION - 5.9L
Engine speed and crankshaft position are provided
through the CKP sensor. The sensor generates pulses
that are the input sent to the Powertrain Control
Module (PCM). The PCM interprets the sensor input
to determine the crankshaft position. The PCM then
uses this position, along with other inputs, to deter-
mine injector sequence and ignition timing.
The sensor is a hall effect device combined with an
internal magnet. It is also sensitive to steel within a
certain distance from it.
On 5.9L V-8 engines, the flywheel/drive plate has 8
single notches, spaced every 45 degrees, at its outer
edge (Fig. 24).
The notches cause a pulse to be generated when
they pass under the sensor. The pulses are the input
to the PCM. For each engine revolution, there are 8
pulses generated on V-8 engines.
The engine will not operate if the PCM does not
receive a CKP sensor input.
Fig. 22 Accelerator PedalÐRemoval or Installation
1 - PEDAL MOUNTING BRACKET
2 - PIVOTS/BUSHINGS
3 - PEDAL/BRACKET
4 - PIVOT PIN
Fig. 23 CKP Sensor LocationÐ8.0L V-10 Engine
1 - CRANKSHAFT POSITION SENSOR
2 - HOLE
3 - OIL FILTER
4 - PLASTIC TIE STRAP
5 - PIGTAIL HARNESS
BR/BEFUEL INJECTION - GASOLINE 14 - 37
ACCELERATOR PEDAL (Continued)

OPERATION - 8.0L
The Crankshaft Position (CKP) sensor detects
notches machined into the middle of the crankshaft
(Fig. 25).There are five sets of notches. Each set contains
two notches. Basic ignition timing is determined by
the position of the last notch in each set of notches.
Once the Powertrain Control Module (PCM) senses
the last notch, it will determine crankshaft position
(which piston will next be at Top Dead Center). An
input from the camshaft position sensor is also
needed. It may take the module up to one complete
engine revolution to determine crankshaft position
during engine cranking.
The PCM uses the signal from the camshaft posi-
tion sensor to determine fuel injector sequence. Once
crankshaft position has been determined, the PCM
begins energizing a ground circuit to each fuel injec-
tor to provide injector operation.
REMOVAL
REMOVAL - 5.9L
The sensor is bolted to the top of the cylinder block
near the rear of right cylinder head (Fig. 26).
(1) Remove the air cleaner intake tube.
(2) Disconnect crankshaft position sensor pigtail
harness from main wiring harness.
(3) Remove two sensor (recessed hex head) mount-
ing bolts (Fig. 26).
(4) Remove sensor from engine.
Fig. 24 CKP Sensor OperationÐ5.9L Engine
1 - CRANKSHAFT POSITION SENSOR
2 - NOTCHES
3 - FLYWHEEL
Fig. 25 CKP Sensor OperationÐ8.0L V-10 Engine
1 - CRANKSHAFT NOTCHES
2 - CRANKSHAFT
3 - CRANKSHAFT POSITION SENSOR
Fig. 26 Crankshaft Position Sensor
1 - GROMMET
2 - MOUNTING BOLTS (2)
3 - CRANKSHAFT POSITION SENSOR
4 - RIGHT EXHAUST MANIFOLD
5 - TRANSMISSION BELL HOUSING
14 - 38 FUEL INJECTION - GASOLINEBR/BE
CRANKSHAFT POSITION SENSOR (Continued)

INSTALLATION
INSTALLATION - 5.9L
The IAC motor is located on the back of the throt-
tle body (Fig. 31).
(1) Install IAC motor to throttle body.
(2) Install and tighten two mounting bolts (screws)
to 7 N´m (60 in. lbs.) torque.
(3) Install electrical connector.
(4) Install air cleaner assembly.
INSTALLATION - 8.0L
The IAC motor is located on the back of the throt-
tle body (Fig. 32).
(1) Install IAC motor to throttle body.
(2) Install and tighten two mounting bolts (screws)
to 7 N´m (60 in. lbs.) torque.
(3) Install electrical connector.
(4) Install air cleaner housing to throttle body.
(5) Install 4 air cleaner housing mounting nuts.
Tighten nuts to 11 N´m (96 in. lbs.) torque.
(6) Install air cleaner housing cover.
INTAKE AIR TEMPERATURE
SENSOR
DESCRIPTION - 5.9L/8.0L
The 2±wire Intake Manifold Air Temperature (IAT)
sensor is installed in the intake manifold with the
sensor element extending into the air stream.
The IAT sensor is a two-wire Negative Thermal
Coefficient (NTC) sensor. Meaning, as intake mani-
fold temperature increases, resistance (voltage) in thesensor decreases. As temperature decreases, resis-
tance (voltage) in the sensor increases.
OPERATION - 5.9L/8.0L
The IAT sensor provides an input voltage to the
Powertrain Control Module (PCM) indicating the
density of the air entering the intake manifold based
upon intake manifold temperature. At key-on, a
5±volt power circuit is supplied to the sensor from
the PCM. The sensor is grounded at the PCM
through a low-noise, sensor-return circuit.
The PCM uses this input to calculate the following:
²Injector pulse-width
²Adjustment of spark timing (to help prevent
spark knock with high intake manifold air-charge
temperatures)
The resistance values of the IAT sensor is the same
as for the Engine Coolant Temperature (ECT) sensor.
REMOVAL
REMOVAL - 5.9L
The intake manifold air temperature sensor is
located in the front/side of the intake manifold (Fig.
33).
(1) Remove air cleaner assembly.
(2) Disconnect electrical connector at sensor (Fig.
33).
(3) Remove sensor from intake manifold.
Fig. 32 IAC MotorÐ8.0L Engine
1 - IDLE AIR CONTROL MOTOR
2 - INTAKE MANIFOLD (UPPER HALF)
3 - THROTTLE POSITION SENSOR
4 - THROTTLE BODY
Fig. 33 Air Temperature SensorÐ5.9L
1 - INTAKE MANIFOLD AIR TEMPERATURE SENSOR
2 - ELECTRICAL CONNECTOR
14 - 42 FUEL INJECTION - GASOLINEBR/BE
IDLE AIR CONTROL MOTOR (Continued)

REMOVAL - 8.0L
The intake manifold air temperature sensor is
located in the side of the intake manifold near the
front of throttle body (Fig. 34).
(1) Disconnect electrical connector at sensor.
(2) Remove sensor from intake manifold.
INSTALLATION
INSTALLATION - 5.9L
The intake manifold air temperature sensor is
located in the front/side of the intake manifold (Fig.
33).
(1) Install sensor to intake manifold. Tighten to
12±15 N´m (110±130 in. lbs.) torque.
(2) Install electrical connector.
(3) Install air cleaner.
INSTALLATION - 8.0L
The intake manifold air temperature sensor is
located in the side of the intake manifold near the
front of throttle body (Fig. 34).
(1) Install sensor to intake manifold. Tighten to
12±15 N´m (110±130 in. lbs.) torque.
(2) Install electrical connector.
MANIFOLD ABSOLUTE
PRESSURE SENSOR
DESCRIPTION - 5.9L/8.0L
On 5.9L engines, the MAP sensor is mounted on
the side of the engine throttle body. The sensor is
connected to the throttle body with a rubber
L-shaped fitting.On the 8.0L 10±cylinder engine, the MAP sensor is
mounted into the right side of the intake manifold.
OPERATION - 5.9L/8.0L
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 air
density 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
Fig. 34 Air Temperature SensorÐ8.0L Engine
1 - INTAKE MANIFOLD AIR TEMP. SENSOR
2 - INTAKE MANIFOLD
BR/BEFUEL INJECTION - GASOLINE 14 - 43
INTAKE AIR TEMPERATURE SENSOR (Continued)

(2) Clean the area around the sensor before
removal.
(3) Remove the two sensor mounting bolts.
(4) Remove the sensor from the intake manifold.
INSTALLATION
INSTALLATION - 5.9L
The MAP sensor is located on the front of the
throttle body (Fig. 35). An L-shaped rubber fitting is
used to connect the MAP sensor to throttle body (Fig.
36).
(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).
Tighten screws to 3 N´m (25 in. lbs.) torque.
(4) Install air cleaner.
INSTALLATION - 8.0L
The MAP sensor is mounted into the right upper
side of the intake manifold (Fig. 37). A rubber gasket
is used to seal the sensor to the intake manifold. The
rubber gasket is part of the sensor and is not ser-
viced separately.
(1) Check the condition of the sensor seal. Clean
the sensor and lubricate the rubber gasket with clean
engine oil.
(2) Clean the sensor opening in the intake mani-
fold.
(3) Install the sensor into the intake manifold.
(4) Install sensor mounting bolts. Tighten bolts to
2 N´m (20 in. lbs.) torque.
(5) Install the electrical connector to sensor.
O2 SENSOR
DESCRIPTION
The Oxygen Sensors (O2S) are attached to, and
protrude into the vehicle exhaust system. Depending
on the emission package, the vehicle may use a total
of either 2 or 4 sensors.
Medium and Heavy Duty 8.0L V-10 Engine:
Four sensors are used (2 upstream, 1 pre-catalyst
and 1 post-catalyst). With this emission package, the
1/1 upstream sensor (left side) is located in the left
exhaust downpipe before both the pre-catalyst sensor
(1/2), and the main catalytic convertor. The 2/1
upstream sensor (right side) is located in the right
exhaust downpipe before both the pre-catalyst sensor
(1/2), and the main catalytic convertor. The pre-cata-
lyst sensor (1/2) is located after the 1/1 and 2/1 sen-
sors, and just before the main catalytic convertor.
The post-catalyst sensor (1/3) is located just after the
main catalytic convertor.
Heavy Duty 5.9L Engine:Two sensors are used.
They arebothreferred to as upstream sensors (left
side is referred to as 1/1 and right side is referred to
as 2/1). With this emission package, a sensor is
located in each of the exhaust downpipes before the
main catalytic convertor.
OPERATION
An O2 sensor is a galvanic battery that provides
the PCM with a voltage signal (0-1 volt) inversely
proportional to the amount of oxygen in the exhaust.
In other words, if the oxygen content is low, the volt-
age output is high; if the oxygen content is high the
output voltage is low. The PCM uses this information
to adjust injector pulse-width to achieve the
14.7±to±1 air/fuel ratio necessary for proper engine
operation and to control emissions.
The O2 sensor must have a source of oxygen from
outside of the exhaust stream for comparison. Cur-
rent O2 sensors receive their fresh oxygen (outside
air) supply through the O2 sensor case housing.
Four wires (circuits) are used on each O2 sensor: a
12±volt feed circuit for the sensor heating element; a
ground circuit for the heater element; a low-noise
sensor return circuit to the PCM, and an input cir-
cuit from the sensor back to the PCM to detect sen-
sor operation.
Oxygen Sensor Heaters/Heater Relays:
Depending on the emissions package, the heating ele-
ments within the sensors will be supplied voltage
from either the ASD relay, or 2 separate oxygen sen-
sor relays. Refer to 8, Wiring Diagrams to determine
which relays are used.
The O2 sensor uses a Positive Thermal Co-efficient
(PTC) heater element. As temperature increases,
resistance increases. At ambient temperatures
Fig. 37 MAP Sensor LocationÐ8.0L V-10 EngineÐ
Typical
1 - MAP SENSOR
2 - MOUNTING BOLTS
3 - THROTTLE BODY
BR/BEFUEL INJECTION - GASOLINE 14 - 45
MANIFOLD ABSOLUTE PRESSURE SENSOR (Continued)

around 70ÉF, the resistance of the heating element is
approximately 4.5 ohms. As the sensor's temperature
increases, resistance in the heater element increases.
This allows the heater to maintain the optimum
operating temperature of approximately 930É-1100ÉF
(500É-600É C). Although the sensors operate the
same, there are physical differences, due to the envi-
ronment that they operate in, that keep them from
being interchangeable.
Maintaining correct sensor temperature at all
times allows the system to enter into closed loop
operation sooner. Also, it allows the system to remain
in closed loop operation during periods of extended
idle.
In Closed Loop operation, the PCM monitors cer-
tain O2 sensor input(s) along with other inputs, and
adjusts the injector pulse width accordingly. During
Open Loop operation, the PCM ignores the O2 sensor
input. The PCM adjusts injector pulse width based
on preprogrammed (fixed) values and inputs from
other sensors.
Upstream Sensors:Two upstream sensors are
used (1/1 and 2/1). The 1/1 sensor is the first sensor
to receive exhaust gases from the #1 cylinder. They
provide an input voltage to the PCM. The input tells
the PCM the oxygen content of the exhaust gas. The
PCM uses this information to fine tune fuel delivery
to maintain the correct oxygen content at the down-
stream oxygen sensors. The PCM will change the air/
fuel ratio until the upstream sensors input a voltage
that the PCM has determined will make the down-
stream sensors output (oxygen content) correct.
The upstream oxygen sensors also provide an input
to determine mini-catalyst efficiency. Main catalytic
convertor efficiency is not calculated with this pack-
age.
Downstream Sensors:Two downstream sensors
are used (1/2 and 2/2). The downstream sensors are
used to determine the correct air-fuel ratio. As the
oxygen content changes at the downstream sensor,
the PCM calculates how much air-fuel ratio change is
required. The PCM then looks at the upstream oxy-
gen sensor voltage, and changes fuel delivery until
the upstream sensor voltage changes enough to cor-
rect the downstream sensor voltage (oxygen content).
The downstream oxygen sensors also provide an
input to determine mini-catalyst efficiency. Main cat-
alytic convertor efficiency is not calculated with this
package.
Medium and Heavy Duty 8.0L V-10 Engine:
Four oxygen sensors are used (2 upstream, 1 pre-cat-
alyst and 1 post-catalyst). The upstream sensors (1/1
and 2/1) will fine-tune the air-fuel ratio through the
Powertrain Control Module (PCM). The pre-catalyst
(1/2) and post-catalyst (1/3) sensors will determine
catalytic convertor efficiency (efficiency of the maincatalytic convertor). This is also done through the
PCM.
Heavy Duty 5.9L Engine:Downstream sensors
are not used with this emissions package, meaning
catalytic convertor efficiency is not calculated with
this package. Two upstream sensors are used. The
left upstream sensor (1/1) will monitor cylinders 1, 3,
5 and 7. The right upstream sensor (2/1) will monitor
cylinders 2, 4, 6 and 8. The PCM monitors the oxy-
gen content of the sensors, and will fine-tune the air-
fuel ratio.
Engines equipped with either a downstream sen-
sor(s), or a post-catalytic sensor, will monitor cata-
lytic convertor efficiency. If efficiency is below
emission standards, the Malfunction Indicator Lamp
(MIL) will be illuminated and a Diagnostic Trouble
Code (DTC) will be set. Refer to Monitored Systems
in Emission Control Systems for additional informa-
tion.
REMOVAL
Never apply any type of grease to the oxygen
sensor electrical connector, or attempt any sol-
dering of the sensor wiring harness.
The O2S (oxygen sensors) are numbered 1/1, 1/2,
1/3, 2/1 and 2/2.
On HDC engines, the pre-catalyst/post catalyst
O2S sensors are located at the inlet and outlet ends
of the catalytic converter (Fig. 38).
The 1/1 and 2/1 sensors are located before the
mini-cats (Fig. 39). The 1/2 and 2/2 sensors are
located after the mini-cats (Fig. 39).
WARNING: THE EXHAUST MANIFOLD, EXHAUST
PIPES AND CATALYTIC CONVERTER BECOME
VERY HOT DURING ENGINE OPERATION. ALLOW
ENGINE TO COOL BEFORE REMOVING OXYGEN
SENSOR.
Fig. 38 Pre-catalyst/Post catalyst Oxygen SensorsÐ
HDC Engines
1 - POST CATALYST OXYGEN SENSOR (1/3)
2 - PRE-CATALYST OXYGEN SENSOR (1/2)
14 - 46 FUEL INJECTION - GASOLINEBR/BE
O2 SENSOR (Continued)

(1) Raise and support the vehicle.
(2) Disconnect the wire connector from the O2S
sensor.
CAUTION: When disconnecting the sensor electrical
connector, do not pull directly on wire going into
sensor.
(3) Remove the O2S sensor with an oxygen sensor
removal and installation tool.
INSTALLATION
Threads of new oxygen sensors are factory coated
with anti-seize compound to aid in removal.DO
NOT add any additional anti-seize compound to
the threads of a new oxygen sensor.
(1) Install the O2S sensor. Tighten to 30 N´m (22
ft. lbs.) torque.
(2) Connect the O2S sensor wire connector.
(3) Lower the vehicle.
PTO SWITCH
DESCRIPTION
This Powertrain Control Module (PCM) input is
used only on models equipped with aftermarket
Power Take Off (PTO) units.
OPERATION
The input is used only to tell the PCM that the
PTO has been engaged. The PCM will disable (tem-
porarily shut down) certain OBD II diagnostic trou-
ble codes when the PTO is engaged.
When the aftermarket PTO switch has been
engaged, a 12V + signal is sent through circuit G113
to PCM pin A13. The PCM will then sense and deter-
mine that the PTO has been activated.
THROTTLE BODY
DESCRIPTION
The throttle body is located on the intake manifold.
Fuel does not enter the intake manifold through the
throttle body. Fuel is sprayed into the manifold by
the fuel injectors.
OPERATION
Filtered air from the air cleaner enters the intake
manifold through the throttle body. The throttle body
contains an air control passage controlled by an Idle
Air Control (IAC) motor. The air control passage is
used to supply air for idle conditions. A throttle valve
(plate) is used to supply air for above idle conditions.
Certain sensors are attached to the throttle body.
The accelerator pedal cable, speed control cable and
transmission control cable (when equipped) are con-
nected to the throttle body linkage arm.
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate.Never attempt to adjust the engine idle
speed using this screw.All idle speed functions are
controlled by the PCM.
REMOVAL
REMOVAL - 5.9L
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate.Never attempt to adjust the engine idle
speed using this screw.All idle speed functions are
controlled by the powertrain control module (PCM).
(1) Remove the air cleaner.
(2) Disconnect throttle body electrical connectors
at MAP sensor, IAC motor and TPS (Fig. 40).
(3) Remove vacuum line at throttle body.
(4) Remove all control cables from throttle body
(lever) arm. Refer to the Accelerator Pedal and Throt-
tle Cable section of this group for additional informa-
tion.
(5) Remove four throttle body mounting bolts (Fig.
41).
(6) Remove throttle body from intake manifold.
(7) Discard old throttle body-to-intake manifold
gasket.
REMOVAL - 8.0L
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate.Never attempt to adjust the engine idle
speed using this screw.All idle speed functions are
controlled by the powertrain control module (PCM).
(1) Remove the air cleaner cover.
Fig. 39 Oxygen SensorsÐ5.9L California Engines
BR/BEFUEL INJECTION - GASOLINE 14 - 47
O2 SENSOR (Continued)