ignition DODGE NEON 1999 Service Repair Manual

disables the A/C compressor clutch for several sec-
onds.
The air conditioning clutch relay is located in the
PDC. The inside top of the PDC cover has a label
showing relay and fuse location.
AUTOMATIC SHUTDOWN RELAYÐPCM OUTPUT
The automatic shutdown (ASD) relay supplies bat-
tery voltage to the fuel injectors, electronic ignition
coil and the heating elements in the oxygen sensors.
A buss bar in the power distribution center (PDC)
supplies voltage to the solenoid side and contact side
of the relay. The ASD relay power circuit contains a
20 amp fuse between the buss bar in the PDC and
the relay. The fuse also protects the power circuit for
the fuel pump relay and pump. The fuse is located in
the PDC. Refer to Group 8W, Wiring Diagrams for
circuit information.
The PCM controls the relay by switching the
ground path for the solenoid side of the relay on and
off. The PCM turns the ground path off when the
ignition switch is in the Off position unless the 02
Heater Monitor test is being run. Refer to Group 25,
On-Board Diagnostics. When the ignition switch is in
the On or Crank position, the PCM monitors the
crankshaft position sensor and camshaft position sen-
sor signals to determine engine speed and ignition
timing (coil dwell). If the PCM does not receive the
crankshaft position sensor and camshaft position sen-
sor signals when the ignition switch is in the Run
position, it will de- energize the ASD relay.
The ASD relay is located in the PDC. The inside
top of the PDC cover has a label showing relay and
fuse location.
CHARGING SYSTEM INDICATOR LAMPÐPCM
OUTPUT
The PCM turns the instrument panel Charging
System Lamp on. Refer to Group 8C for charging sys-
tem information.
FUEL PUMP RELAYÐPCM OUTPUT
The fuel pump relay supplies battery voltage to the
fuel pump. A buss bar in the Power Distribution Cen-
ter (PDC) supplies voltage to the solenoid side and
contact side of the relay. The fuel pump relay power
circuit contains a 20 amp fuse between the buss bar
in the PDC and the relay. The fuse also protects the
power circuit for the Automatic Shutdown (ASD)
relay. The fuse is located in the PDC. Refer to Group
8W, Wiring Diagrams for circuit information.
The PCM controls the fuel pump relay by switch-
ing the ground path for the solenoid side of the relay
on and off. The PCM turns the ground path off when
the ignition switch is in the Off position. When the
ignition switch is in the On position, the PCM ener-gizes the fuel pump. If the crankshaft position sensor
does not detect engine rotation, the PCM de-ener-
gizes the relay after approximately one second.
The fuel pump relay is located in the PDC. The
inside top of the PDC cover has a label showing relay
and fuse location.
DUTY CYCLE EVAP PURGE SOLENOIDÐPCM
OUTPUT
The duty cycle EVAP purge solenoid regulates the
rate of vapor flow from the EVAP canister to the
throttle body. The powertrain control module oper-
ates the solenoid.
During the cold start warm-up period and the hot
start time delay, the PCM does not energize the sole-
noid. When de-energized, no vapors are purged.
The engine enters closed loop operation after it
reaches a specified temperature and the programmed
time delay ends. During closed loop operation, the
PCM energizes and de-energizes the solenoid 5 to 10
times per second, depending upon operating condi-
tions. The PCM varies the vapor flow rate by chang-
ing solenoid pulse width. Pulse width is the amount
of time the solenoid is energized.
The solenoid attaches to a bracket near the front
engine mount (Fig. 22). To operate correctly, the sole-
noid must be installed with the electrical connector
on top.
ELECTRIC EGR TRANSDUCERÐPCM OUTPUT
The Electric EGR Transducer contains an electri-
cally operated solenoid and a back-pressure con-
trolled vacuum transducer (Fig. 23). The PCM
Fig. 22 Duty Cycle EVAP Purge Solenoid
14 - 32 FUEL SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

FUEL INJECTORSÐPCM OUTPUT
The 2.0L engine uses electrically operated top feed
fuel injectors (Fig. 26). The Automatic Shutdown
(ASD) relay supplies battery voltage to the fuel injec-
tors. The PCM controls the ground path for each
injector in sequence. By switching the ground paths
on and off, the PCM fine-tunes injector pulse width.
Injector pulse width refers to the amount of time an
injector operates.
The PCM determines injector synchronization from
the camshaft position sensor and crankshaft position
sensor inputs. The PCM grounds the ASD and fuel
pump relays after receiving the camshaft position
sensor and crankshaft position sensor inputs.
The PCM energizes the injectors in a sequential
order during all engine operating conditions except
start-up. For the first injector pulse width during
start-up, all injectors are energized at the same time.
Once the PCM determines crankshaft position, it
begins energizing the injectors in sequence.
IGNITION COILÐPCM OUTPUT
The coil assembly consists of 2 coils molded
together. The coil assembly is mounted over the valve
cover (Fig. 27) or (Fig. 28). High tension leads route
to each cylinder from the coil. The coil fires two
spark plugs every power stroke. One plug is the cyl-
inder under compression, the other cylinder fires on
the exhaust stroke. Coil number one fires cylinders 1
and 4. Coil number two fires cylinders 2 and 3. The
PCM determines which of the coils to charge and fire
at the correct time.
The Auto Shutdown (ASD) relay provides battery
voltage to the ignition coil. The PCM provides a
ground contact (circuit) for energizing the coil. When
the PCM breaks the contact, the energy in the coil
primary transfers to the secondary causing the
spark. The PCM will de-energize the ASD relay if it
does not receive the crankshaft position sensor andcamshaft position sensor inputs. Refer to Auto Shut-
down (ASD) RelayÐPCM Output in this section for
relay operation.
MALFUNCTION INDICATOR (CHECK ENGINE)
LAMPÐPCM OUTPUT
The PCM supplies the malfunction indicator (check
engine) lamp on/off signal to the instrument panel
through the CCD Bus. The CCD Bus is a communi-
cations port. Various modules use the CCD Bus to
exchange information.
The Check Engine lamp comes on each time the
ignition key is turned ON and stays on for 3 seconds
as a bulb test.
The Malfunction Indicator Lamp (MIL) stays on
continuously, when the PCM has entered a Limp-In
mode or identified a failed emission component. Dur-
ing Limp-in Mode, the PCM attempts to keep the
system operational. The MIL signals the need for
immediate service. In limp-in mode, the PCM com-
pensates for the failure of certain components that
Fig. 26 Fuel Injector
Fig. 27 Ignition Coil PackÐSOHC
Fig. 28 Ignition Coil PackÐDOHC
14 - 34 FUEL SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

(3) Open the Power Distribution Center (PDC).
Check for blown fuses. Ensure the relays and fuses
are fully seated in the PDC (Fig. 32). A label on the
underside of the PDC cover shows the locations of
each relay and fuse.
(4) Verify the throttle cable operates freely (Fig.
33).
(5) Check the electrical connections at the idle air
control motor and throttle position sensor (Fig. 34).
(6) Check hose connections between the PCV
valve, vacuum port - intake manifold and the oil sep-
arator (Fig. 35).
(7) Inspect the electrical connections at the MAP
sensor/intake air temperature sensor and the (Fig.
36).
(8) Inspect the fuel injector electrical connections
(Fig. 37).
(9) Inspect the ignition coil electrical connector.
Ensure the spark plug insulators are firmly seated
over the spark plugs (Fig. 38).
Fig. 30 2.0L SOHC Engine Compartment
Fig. 31 Battery, PCM, and PDC
Fig. 32 Power Distribution Center
Fig. 33 Throttle CableÐAutomatic Transmission
Fig. 34 Idle Air Control Motor and Throttle Position
SensorÐTypical
14 - 36 FUEL SYSTEMPL
DIAGNOSIS AND TESTING (Continued)

(10) Inspect the electrical and hose connections at
the duty cycle purge solenoid (Fig. 39).(11) Check the electrical connection to the radiator
fan.
(12) Inspect for corrosion on the electrical connec-
tions at the starter motor solenoid. Check the ground
cable connection below the starter motor (Fig. 40).
(13) Inspect the air cleaner filter element. Replace
as necessary. Check the air induction system for
restrictions.
Fig. 35 PCV Valve
Fig. 36 MAP/Intake Air Temperature Sensor
Fig. 37 Fuel Injectors
Fig. 38 Ignition Coil and Spark PlugsÐTypical
PLFUEL SYSTEM 14 - 37
DIAGNOSIS AND TESTING (Continued)

(6) Check hose connections between the PCV
valve, vacuum port - intake manifold and the oil sep-
arator (Fig. 58).
(7) Inspect the electrical connections at the MAP
sensor/intake air temperature sensor and the (Fig.
59).
(8) Inspect the fuel injector electrical connections
(Fig. 60).
(9) Inspect the ignition coil electrical connector.
Ensure the spark plug insulators are firmly seated
over the spark plugs (Fig. 61).
(10) Inspect the electrical and hose connections at
the duty cycle purge solenoid (Fig. 62).
(11) Check the electrical connection to the radiator
fan.
(12) Inspect for corrosion on the electrical connec-
tions at the starter motor solenoid. Check the ground
cable connection below the starter motor (Fig. 63).
Fig. 58 PCV Valve
Fig. 59 MAP/Intake Air Temperature Sensor
Fig. 60 Fuel InjectorsÐTypical
Fig. 61 Ignition Coil and Spark Plugs
Fig. 62 Duty Cycle Purge Solenoid
14 - 42 FUEL SYSTEMPL
DIAGNOSIS AND TESTING (Continued)

(7) Attach the other end of the jumper wire to
relay terminal 86. This activates the relay. The ohm-
meter should now show continuity between relay ter-
minals 87 and 30. The ohmmeter should not show
continuity between relay terminals 87A and 30.
(8) Disconnect jumper wires.
(9) Replace the relay if it did not pass the continu-
ity and resistance tests. If the relay passed the tests,
it operates properly. Check the remainder of the ASD
and fuel pump relay circuits. Refer to group 8W, Wir-
ing Diagrams.
CAMSHAFT AND CRANKSHAFT POSITION SENSOR
Refer to Group 8D, Ignition for Diagnosis and Test-
ing of Camshaft and Crankshaft Sensors.
ENGINE COOLANT TEMPERATURE SENSOR
(1) With the key off, disconnect wire harness con-
nector from coolant temperature sensor (Fig. 79) or
(Fig. 80).(2) Connect a high input impedance (digital) volt-
ohmmeter to terminals A and B (Fig. 81). The ohm-
meter should read as follows:
²Engine/Sensor at normal operating temperature
around 200ÉF should read approximately 700 to
1,000 ohms.
²Engine/Sensor at room temperature around 70ÉF
ohmmeter should read approximately 7,000 to 13,000
ohms.
(3) T
est the resistance of the wire harness between
the PCM 60-way connector terminal 28 and the sensor
harness connector. Also check for continuity between
PCM 60-way connector terminal 51 and the sensor har-
ness connector. Refer to Group 8W, Wiring diagrams for
circuit information. If the resistance is greater than 1
ohm, repair the wire harness as necessary.
HEATED OXYGEN SENSOR
Use an ohmmeter to test the heating element of
the oxygen sensors. Disconnect the electrical connec-
tor from each oxygen sensor. The white wires in the
sensor connector are the power and ground circuits
for the heater. Connect the ohmmeter test leads to
terminals of the white wires in the heated oxygen
sensor connector. Replace the heated oxygen sensor if
the resistance is not between 4 and 7 ohms.
IDLE AIR CONTROL (IAC) MOTOR TEST
To preform a complete test of IAC motor and its
circuitry, refer to DRB scan tool and the appropriate
Powertrain Diagnostics Procedures manual.
KNOCK SENSOR
The engine knock sensor is affected by a number of
factors. A few of these are: ignition timing, cylinder
pressure, fuel octane, etc. The knock sensor generates
an AC voltage whose amplitude increases with the
increase of engine knock. The knock sensor can be
tested with a digital voltmeter. The RMS voltage starts
Fig. 79 Engine Coolant Temperature Sensor
LocationÐSOHC
Fig. 80 Engine Coolant Temperature Sensor
LocationÐDOHC
Fig. 81 Engine Coolant Temperature Sensor
PLFUEL SYSTEM 14 - 47
DIAGNOSIS AND TESTING (Continued)

at about 20mVac (at about 700 rpm) and increases to
approximately 600 mVac (5000 rpm). If the output falls
outside of this range a DTC will be set.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
To perform a complete test of the MAP sensor and
its circuitry, refer to the DRB scan tool and appropri-
ate Powertrain Diagnostics Procedures manual. To
test the MAP sensor only, refer to the following:
CAUTION: When testing the MAP sensor, be sure
that the harness wires are not damaged by the test
meter probes.
(1) Test the MAP sensor output voltage at the
MAP sensor connector between terminals 1 and 4
(Fig. 82). With the ignition switch ON and the engine
not running, output voltage should be 4 to 5 volts.
The voltage should drop to 1.5 to 2.1 volts with a hot,
neutral idle speed condition. If OK, go to next step. If
not OK, go to step 3.
(2) Test PCM terminal 36 for the same voltage
described in the previous step to verify wire harness
condition. Repair as required.
(3) Test the MAP sensor ground circuit at sensor
connector terminal 1 and PCM terminal 43. If OK, go
to next step. If not OK, repair as required.
(4) Test MAP sensor supply voltage between sen-
sor connector terminals 3 and 1 with the key ON.
The voltage should be approximately 5 volts (6.5V).
Five volts (6.5V) should also be at terminal 61 of the
PCM. If OK, replace MAP sensor. If not OK, repair or
replace the wire harness as required.
THROTTLE POSITION SENSOR
To perform a complete test of the this sensor and
its circuitry, refer to the DRB scan tool and appropri-
ate Powertrain Diagnostics Procedures manual. To
test the throttle position sensor only, refer to the fol-
lowing:
The Throttle Position Sensor (TPS) can be tested
with a digital voltmeter (DVM). The center terminal
of the sensor is the output terminal. One of the other
terminals is a 5 volt supply and the remaining ter-
minal is ground.
Connect the DVM between the center and sensor
ground terminal. Refer to Group 8W - Wiring Dia-
grams for correct pinout.
With the ignition switch in the ON position, check
the output voltage at the center terminal wire of the
connector. Check the output voltage at idle and at
Wide-Open-Throttle (WOT). At idle, TPS output volt-
age should be approximately 0.38 volts to 1.2 volts.
At wide open throttle, TPS output voltage should be
approximately 3.1 volts to 4.4 volts. The output volt-
age should gradually increase as the throttle plate
moves slowly from idle to WOT.
Check for spread terminals at the sensor and PCM
connections before replacing the TPS.
THROTTLE BODY MINIMUM AIR FLOW
(1) Turn ignition key to Off.
(2) Disconnect the PCV valve hose from the intake
manifold nipple (Fig. 83). Cap the PCV vacuum nip-
ple.
(3) Disconnect purge hose from the nipple on the
throttle body (Fig. 84).
(4) Use a piece of hose to attach Air Metering Ori-
fice 6457 (0.125 in. orifice) to the purge nipple on the
throttle body (Fig. 85).
(5) Ensure that all accessories are off.
Fig. 82 MAP Sensor Connector
Fig. 83 PCV Vacuum Nipple
14 - 48 FUEL SYSTEMPL
DIAGNOSIS AND TESTING (Continued)

(5) Install throttle body. Refer to Throttle Body in
this section.
(6) Connect the EVAP purge hose to the throttle
body nipple.
(7) Connect negative cable to battery.
MAP/IAT SENSORÐSOHC
The MAP/IAT sensor attaches to the intake mani-
fold plenum (Fig. 96).
REMOVAL
(1) Disconnect the electrical connector from the
MAP/IAT sensor.
(2) Remove sensor mounting screws.
(3) Remove sensor.
INSTALLATION
(1) Insert sensor into intake manifold while mak-
ing sure not to damage O-ring seal.
(2) Tighten mounting screws to 2 N´m (20 in. lbs)
torque for plastic manifold and 3 N´m (30 in. lbs.) for
aluminum manifold.
(3) Attach electrical connector to sensor.
MAP/IAT SENSORÐDOHC
The MAP/IAT sensor attaches to the intake mani-
fold plenum (Fig. 98).
REMOVAL
(1) Remove air inlet duct wing nut and duct from
intake manifold (Fig. 97).
(2) Disconnect the electrical connector from the
MAP/IAT sensor.
(3) Remove sensor mounting screws.
(4) Remove sensor.
INSTALLATION
(1) Insert sensor into intake manifold while mak-
ing sure not to damage O-ring seals.(2) Tighten mounting screws to 2 N´m (20 in. lbs)
torque foe a plastic manifold and 3 N´m (30 in. lbs)
for a aluminum manifold.
(3) Attach electrical connector to sensor.
(4) Install air inlet duct wing nut and duct from
intake manifold, insure that the duct does not inter-
fer with ignition cables.
DUTY CYCLE EVAP PURGE SOLENOID VALVE
The solenoid attaches to a bracket near the front
engine mount (Fig. 99). The solenoid will not operate
unless it is installed correctly.
REMOVAL
(1) Disconnect electrical connector from solenoid.
(2) Disconnect vacuum tubes from solenoid.
Fig. 95 Servicing Idle Air Control MotorFig. 96 MAP/IAT SensorÐSOHC
Fig. 97 Air Inlet DuctÐDOHC
PLFUEL SYSTEM 14 - 53
REMOVAL AND INSTALLATION (Continued)

(3) Remove solenoid from bracket.
INSTALLATION
The top of the solenoid has TOP printed on it. The
solenoid will not operate unless it is installed cor-
rectly.
(1) Install solenoid on bracket.
(2) Connect vacuum tube to solenoid.
(3) Connect electrical connector to solenoid.
POWERTRAIN CONTROL MODULE (PCM)
The PCM attaches to the inner fender panel next
to the washer fluid bottle on the passenger side (Fig.
100).
REMOVAL
(1) Disconnect negative cable from battery.
(2) Disconnect positive cable from battery.
(3) Remove washer bottle neck.
(4) Squeeze tabs on PDC while pulling PDC up to
remove it from bracket. Lay PDC aside to gain access
to PCM bracket screws.
(5) Remove screws attaching PCM to body.
(6) Lift PCM up and disconnect the 2 40-way con-
nector.
(7) Remove PCM.
INSTALLATION
(1) Attach the 2 40-way connector to PCM.
(2) Install PCM. Tighten mounting screws to 9
N´m (80 in. lbs.) torque.
(3) Install PDC by pushing down into brackets.
(4) Install washer bottle neck.
(5) Connect positive cable to battery.
(6) Connect negative cable to battery.
CRANKSHAFT POSITION SENSOR
For removal/installation procedures refer to group
8D - Ignition System, Service Procedures.
CAMSHAFT POSITION SENSOR
For removal/installation procedures refer to group
8D - Ignition System, Service Procedures.
UPSTREAM HEATED OXYGEN SENSOR
REMOVAL
(1) Raise and support vehicle.
(2) Unplug sensor connector.
(3) Remove sensor using an oxygen sensor crow
foot wrench such as Snap-On tool YA8875 or equiva-
lent (Fig. 101).
(4) A
fter removing the sensor, the exhaust manifold
threads must be cleaned with an 18 mm X 1.5 + 6E tap.
If reusing the original sensor, coat the sensor threads
Fig. 98 MAP/IAT SensorÐDOHC
Fig. 99 Duty Cycle EVAP Purge Solenoid Valve
Fig. 100 Powertrain Control Module
14 - 54 FUEL SYSTEMPL
REMOVAL AND INSTALLATION (Continued)

INSTALLATION
The speed sensor gear meshes with a gear on the
output shaft.
(1) With O-ring in place, install sensor.
(2) Install mounting bolt.
(3) Connect electrical connector to sensor.
KNOCK SENSOR
For removal/installation procedures refer to Group
8D- Ignition System, Service Procedures.
SPECIFICATIONS
VECI LABEL
If anything differs between the specifications found
on the Vehicle Emission Control Information (VECI)
label and the following specifications, use specifica-
tions on VECI label. The VECI label is located in the
engine compartment.
TORQUE
DESCRIPTION TORQUE
Air Cleaner Wingnut..........1.5 N´m (15 in. lbs.)
Air Cleaner Mount. Stud-To-Thrott. Body .10 N´m (90
in. lbs.)
Crankshaft Position Sensor Mounting Bolts.8 N´m (70
in. lbs.)
Engine Coolant Temperature Sensor .18 N´m (165 in.
lbs.)
IAC Motor-To-Throttle Body Bolts .7 N´m (60 in. lbs.)
MAP/IAT Sensor..............2N´m(20in.lbs.)
MAP/IAT Sensor..............3N´m(30in.lbs.)
Oxygen Sensor...............28N´m(20ft.lbs.)
Powertrain Control Module (PCM) Mounting Screws.4
N´m (35 in. lbs.)
Throttle Cable Cover.........4.5 N´m (40 in. lbs.).
Throttle Body Mounting Bolts . .23 N´m (200 in. lbs.)
Throttle Position Sensor Mounting Screws .2 N´m (20
in. lbs.)
Vehicle Speed Sensor Mounting Bolt .2.2 N´m (20 in.
lbs.)
SPECIAL TOOLS
FUEL
Fig. 108 Engine Coolant Temperature SensorÐ
DOHCFig. 109 Vehicle Speed Sensor
Extractor C±4334Pressure Gauge Assembly C±4799±B
PLFUEL SYSTEM 14 - 57
REMOVAL AND INSTALLATION (Continued)