1999 DODGE NEON Service Repair Manual

Use a new spark plug and spark plug cable
for the following test.
(1) Insert a new spark plug into the new spark
plug boot. Ground the plug to the engine (Fig. 17).
Do not hold with your hand.
(2) Starting with coil insulator #1, remove it from
the DIS coil.
(3) Plug the test spark plug cable onto #1 coil
tower. Make sure a good connection is made; there
should be a click sound.
(4) Crank the engine and look for spark across the
electrodes of the spark plug.
CAUTION: Always install the cable back on the coil
tower after testing to avoid damage to the coil and
catalytic converter.
(5) Repeat the above test for the remaining coils. If
there is no spark during all cylinder tests, proceed to
the Failure To Start Test.
(6) If one or more tests indicate irregular, weak, or
no spark, proceed to Check Coil Test.
CHECK COIL TEST
NOTE: Coil one fires cylinders 1 and 4, coil two
fires cylinders 2 and 3. Each coil tower is labeled
with the number of the corresponding cylinder.
(1) Remove the ignition cables and measure the
resistance of the cables. Resistance must be between
ranges shown in chart in specifcation section in this
group. Replace any cable not within tolerance.
(2) Disconnect the electrical connector from the
coil pack.
(3) Measure the primary resistance of each coil. At
the coil, connect an ohmmeter between the B+ pin
and the pin corresponding to the cylinders in ques-
tion (Fig. 18). Resistance on the primary side of eachcoil should be 0.45 - 0.65 ohm. Replace the coil if
resistance is not within tolerance.
(4) Remove ignition cables from the secondary tow-
ers of the coil. Measure the secondary resistance of
the coil between the towers of each individual coil
(Fig. 19). Secondary resistance should be 11,000 to
14,000 ohms. Replace the coil if resistance is not
within tolerance.
FAILURE TO START TESTÐ2.0/2.4L
This no-start test checks the camshaft position sen-
sor and crankshaft position sensor.
Use the DRB scan tool to test the camshaft posi-
tion sensor and the sensor circuits. Refer to the
appropriate Powertrain Diagnostics Procedure Man-
ual. Refer to the wiring diagrams section for circuit
information.
The Powertrain Control Module (PCM) supplies 8
volts to the camshaft position sensor and crankshaft
position sensor through one circuit. If the 8 volt sup-
Fig. 17 Testing For Spark
Fig. 18 Terminal Identification
Fig. 19 Checking Ignition Coil Secondary
Resistance
8D - 8 IGNITION SYSTEMPL
DIAGNOSIS AND TESTING (Continued)

ply circuit shorts to ground, neither sensor will pro-
duce a signal (output voltage to the PCM).
When the ignition key is turned and left in the On
position, the PCM automatically energizes the Auto
Shutdown (ASD) relay. However, the controller de-en-
ergizes the relay within one second because it has
not received a camshaft position sensor signal indi-
cating engine rotation.
During cranking, the ASD relay will not energize
until the PCM receives a camshaft position sensor
signal. Secondly, the ASD relay remains energized
only if the controller senses a crankshaft position
sensor signal immediately after detecting the cam-
shaft position sensor signal.
(1) Check battery voltage. Voltage should approxi-
mately 12.66 volts or higher to perform failure to
start test.
(2) Disconnect the harness connector from the coil
pack (Fig. 20).
(3) Connect a test light to the B+ (battery voltage)
terminal of the coil electrical connector and ground.
The B+ wire for the DIS coil is the center terminal.
Do not spread the terminal with the test light
probe.
(4) Turn the ignition key to theON position.The
test light should flash On and then Off.Do not turn
the Key to off position, leave it in the On posi-
tion.
(a) If the test light flashes momentarily, the
PCM grounded the ASD relay. Proceed to step 5.
(b) If the test light did not flash, the ASD relay
did not energize. The cause is either the relay or
one of the relay circuits. Use the DRB scan tool to
test the ASD relay and circuits. Refer to the appro-
priate Powertrain Diagnostics Procedure Manual.
Refer to the wiring diagrams section for circuit
information.
(5) Crank the engine. (If the key was placed in the
off position after step 4, place the key in the On posi-tion before cranking. Wait for the test light to flash
once, then crank the engine.)
(6) If the test light momentarily flashes during
cranking, the PCM is not receiving a crankshaft posi-
tion sensor signal.
(7) If the test light did not flash during cranking,
unplug the crankshaft position sensor connector.
Turn the ignition key to the off position. Turn the
key to the On position, wait for the test light to
momentarily flash once, then crank the engine. If the
test light momentarily flashes, the crankshaft posi-
tion sensor is shorted and must be replaced. If the
light did not flash, the cause of the no-start is in
either the crankshaft position sensor/camshaft posi-
tion sensor 8 volt supply circuit, or the camshaft
position sensor output or ground circuits.
IGNITION TIMING PROCEDURE
The engines for this vehicle, use a fixed ignition
system. The PCM regulates ignition timing. Basic
ignition timing is not adjustable.
CAMSHAFT POSITION SENSOR AND CRANKSHAFT
POSITION SENSOR
The output voltage of a properly operating cam-
shaft position sensor or crankshaft position sensor
switches from high (5.0 volts) to low (0.3 volts). By
connecting an Moper Diagonostic System (MDS) and
engine analyzer to the vehicle, technicians can view
the square wave pattern.
ENGINE COOLANT TEMPERATURE SENSOR
Refer to Group 14, Fuel System for Diagnosis and
Testing.
INTAKE AIR TEMPERATURE SENSOR
Refer to Group 14, Fuel System, for Diagnosis and
Testing.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
TEST
Refer to Group 14, Fuel System for Diagnosis and
Testing.
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.
Fig. 20 Ignition Coil Engine Harness Connector
PLIGNITION SYSTEM 8D - 9
DIAGNOSIS AND TESTING (Continued)

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.
SPARK PLUG CONDITION
NORMAL OPERATING CONDITIONS
The few deposits present will be probably light tan
or slightly gray in color with most grades of commer-
cial gasoline (Fig. 21). There will not be evidence of
electrode burning. Gap growth will not average more
than approximately 0.025 mm (.001 in) per 1600 km
(1000 miles) of operation for non platinum spark
plugs. Non-platnium spark plugs that have normal
wear can usually be cleaned, have the electrodes filed
and regapped, and then reinstalled.
CAUTION: Never attempt to file the electrodes or
use a wire brush for cleaning platinum spark plugs.
This would damage the platinum pads which would
shorten spark plug life.Some fuel refiners in several areas of the United
States have introduced a manganese additive (MMT)
for unleaded fuel. During combustion, fuel with MMT
may coat the entire tip of the spark plug with a rust
colored deposit. The rust color deposits can be misdi-
agnosed as being caused by coolant in the combustion
chamber. Spark plug performance is not affected by
MMT deposits.
COLD FOULING (CARBON FOULING)
Cold fouling is sometimes referred to as carbon
fouling because the deposits that cause cold fouling
are basically carbon (Fig. 21). A dry, black deposit on
one or two plugs in a set may be caused by sticking
valves or misfire conditions. Cold (carbon) fouling of
the entire set may be caused by a clogged air cleaner.
Cold fouling is normal after short operating peri-
ods. The spark plugs do not reach a high enough
operating temperature during short operating peri-
ods.Replace carbon fouled plugs with new
spark plugs.
FUEL FOULING
A spark plug that is coated with excessive wet fuel
is called fuel fouled. This condition is normally
observed during hard start periods.Clean fuel
fouled spark plugs with compressed air and
reinstall them in the engine.
OIL FOULING
A spark plug that is coated with excessive wet oil
is oil fouled. In older engines, wet fouling can be
caused by worn rings or excessive cylinder wear.
Break-in fouling of new engines may occur before
normal oil control is achieved.Replace oil fouled
spark plugs with new ones.
OIL OR ASH ENCRUSTED
If one or more plugs are oil or ash encrusted, eval-
uate the engine for the cause of oil entering the com-
bustion chambers (Fig. 22). Sometimes fuel additives
can cause ash encrustation on an entire set of spark
plugs.Ash encrusted spark plugs can be cleaned
and reused.
HIGH SPEED MISS
When replacing spark plugs because of a high
speed miss condition;wide open throttle opera-
tion should be avoided for approximately 80 km
(50 miles) after installation of new plugs.This
will allow deposit shifting in the combustion chamber
to take place gradually and avoid plug destroying
splash fouling shortly after the plug change.
Fig. 21 Normal Operation and Cold (Carbon) Fouling
8D - 10 IGNITION SYSTEMPL
DIAGNOSIS AND TESTING (Continued)

ELECTRODE GAP BRIDGING
Loose deposits in the combustion chamber can
cause electrode gap bridging. The deposits accumu-
late on the spark plugs during continuous stop-
and-go driving. When the engine is suddenly
subjected to a high torque load, the deposits partially
liquefy and bridge the gap between the electrodes
(Fig. 23). This short circuits the electrodes.Spark
plugs with electrode gap bridging can be
cleaned and reused.
SCAVENGER DEPOSITS
Fuel scavenger deposits may be either white or yel-
low (Fig. 24). They may appear to be harmful, but
are a normal condition caused by chemical additives
in certain fuels. These additives are designed tochange the chemical nature of deposits and decrease
spark plug misfire tendencies. Notice that accumula-
tion on the ground electrode and shell area may be
heavy but the deposits are easily removed.Spark
plugs with scavenger deposits can be consid-
ered normal in condition, cleaned and reused.
CHIPPED ELECTRODE INSULATOR
A chipped electrode insulator usually results from
bending the center electrode while adjusting the
spark plug electrode gap. Under certain conditions,
severe detonation also can separate the insulator
from the center electrode (Fig. 25).Spark plugs
with chipped electrode insulators must be
replaced.
PREIGNITION DAMAGE
Excessive combustion chamber temperature can
cause preignition damage. First, the center electrode
dissolves and the ground electrode dissolves some-
what later (Fig. 26). Insulators appear relatively
deposit free. Determine if the spark plugs are the
correct type, as specified on the VECI label, or if
Fig. 22 Oil or Ash Encrusted
Fig. 23 Electrode Gap Bridging
Fig. 24 Scavenger Deposits
Fig. 25 Chipped Electrode Insulator
PLIGNITION SYSTEM 8D - 11
DIAGNOSIS AND TESTING (Continued)

other operating conditions are causing engine over-
heating.
SPARK PLUG OVERHEATING
Overheating is indicated by a white or gray center
electrode insulator that also appears blistered (Fig.
27). The increase in electrode gap will be consider-
ably in excess of 0.001 in per 1000 miles of operation.
This suggests that a plug with a cooler heat range
rating should be used. Over advanced ignition tim-
ing, detonation and cooling system malfunctions also
can cause spark plug overheating.
REMOVAL AND INSTALLATION
POWERTRAIN CONTROL MODULE (PCM)
The PCM attaches to the inner fender panel next
to the washer fluid bottle on the driver's side (Fig.
28).
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove positive cable from battery.(3) Remove the washer bottle neck from the rubber
grommet.
(4) Remove screws attaching PCM to body.
(5) Lift PCM up and disconnect two 40-way con-
nectors.
INSTALLATION
(1) Attach two 40-way connectors to PCM.
(2) Install PCM. Tighten mounting screws to 6.75
N´m61 N´m (60 in. lbs.610 in. lbs.) torque.
(3) Install washer bottle neck into the rubber
grommet.
(4) Connect positive cable to battery.
(5) Connect negative cable to battery.
SPARK PLUG SERVICE
Failure to route the cables properly could cause the
radio to reproduce ignition noise, cross ignition of the
spark plugs or short circuit the cables to ground.
REMOVAL
REMOVE CABLES FROM COIL FIRST.
Always remove the spark plug cable by grasping
the top of the spark plug insulator, turning the boot
1/2 turn and pulling straight up in a steady motion.
(1) Remove the spark plug using a quality socket
with a rubber or foam insert.
(2) Inspect the spark plug condition. Refer to
Spark Plug Condition in this section.
INSTALLATION
(1) To avoid cross threading, start the spark plug
into the cylinder head by hand.
(2) Tighten spark plugs to 28 N´m (20 ft. lbs.)
torque.
(3) Install spark plug insulators over spark plugs.
Ensure the top of the spark plug insulator covers the
upper end of the spark plug tube.
Reconnect to coil.
Fig. 26 Preignition Damage
Fig. 27 Spark Plug Overheating
Fig. 28 Powertrain Control Module
8D - 12 IGNITION SYSTEMPL
DIAGNOSIS AND TESTING (Continued)

SPARK PLUG CABLE SERVICE
Failure to route the cables properly could cause the
radio to reproduce ignition noise, cross ignition of the
spark plugs or short circuit the cables to ground.
REMOVAL
Remove spark plug cable from coil frist.
Always remove the spark plug cable by grasping
the top of the spark plug insulator, turning the boot
1/2 turn and pulling straight up in a steady motion.
INSTALLATION
Install spark plug insulators over spark plugs.
Ensure the top of the spark plug insulator covers the
upper end of the spark plug tube.The connect the
other end to coil pack. OnSOHCengines, be sure
that dual plastic clip holds #1,#2 cables off of valve
cover and that PCV hose plastic clip holds #3 cable
away from metal PCV clamp and edge of air duct. On
DOHC, be sure that the plastic clip on PCV hose is
positioned so that cable clip is beneath hose, and that
#1 cable is snapped into this clip to protect it from
metal PCV clamp.
SPARK PLUG TUBES
The spark plugs tubes are pressed into the cylinder
head. Sealant is applied to the end of the tube before
installation. For engine information, refer to Group
9, Engines.
IGNITION COIL
SOHC/DOHC
The electronic ignition coil pack attaches directly
to the valve cover (Fig. 29) or (Fig. 30).
REMOVAL
(1) Disconnect electrical connector from coil pack.
(2) Remove coil pack mounting nuts.
(3) Remove coil pack.
INSTALLATION
(1) Install coil pack on valve cover.
(2) Transfer spark plug cables to new coil pack.
The coil pack towers are numbered with the cylinder
identification. Be sure the ignition cables snap onto
the towers.
AUTOMATIC SHUTDOWN RELAY
The relay is located in the Power Distribution Cen-
ter (PDC) (Fig. 31). The PDC is located next to the
battery in the engine compartment. For the location
of the relay within the PDC, refer to the PDC cover
for location. Check electrical terminals for corrosion
and repair as necessary.CAMSHAFT POSITION SENSORÐSOHC
The camshaft position sensor is mounted to the
rear of the cylinder head (Fig. 32).
REMOVAL
(1) Disconnect the filtered air tube from the throt-
tle body and air cleaner housing. Remove filtered air
tube.
Fig. 29 Electronic Ignition Coil PackÐSOHC
Fig. 30 Electronic Ignition Coil PackÐDOHC
Fig. 31 Power Distribution Center (PDC)
PLIGNITION SYSTEM 8D - 13
REMOVAL AND INSTALLATION (Continued)

(2) Remove the air cleaner inlet tube.
(3) Disconnect electrical connectors from engine
coolant sensor and camshaft position sensor.
(4) Remove brake booster hose and electrical con-
nector from holders on end of cylinder head cover.
(5) Remove camshaft position sensor mounting
screws. Remove sensor.
(6) Loosen screw attaching target magnet to rear
of camshaft (Fig. 33).
INSTALLATION
The target magnet has two locating dowels that fit
into machined locating holes in end of the camshaft.
(1) Install target magnet in end of camshaft.
Tighten mounting screw to 3.4 N´m (30 in. lbs.)
torque.
(2) Install camshaft position sensor. Tighten sensor
mounting screws to 9 N´m (80 in. lbs.) torque.
(3) Place brake booster hose and electrical harness
in holders on end of valve cover.
(4) Attach electrical connectors to coolant tempera-
ture sensor and camshaft position sensor.(5) Install air cleaner inlet tube and filtered air
tube.
CAMSHAFT POSITION SENSORÐDOHC
The camshaft position sensor is mounted to the
rear of the cylinder head (Fig. 34).
REMOVAL
(1) Remove filtered air tube from the throttle body
and air cleaner housing.
(2) Disconnect electrical connector from camshaft
position sensor.
(3) Remove camshaft position sensor mounting
screws. Remove sensor.
(4) Loosen screw attaching target magnet to rear
of camshaft (Fig. 35).
INSTALLATION
The target magnet has locating dowels that fit into
machined locating holes in the end of the camshaft
(Fig. 36).
Fig. 32 Camshaft Position Sensor LocationÐSOHC
Fig. 33 Target Magnet Removal/Installation
Fig. 34 Camshaft Position Sensor LocationÐDOHC
Fig. 35 Target Magnet Removal/Installation
8D - 14 IGNITION SYSTEMPL
REMOVAL AND INSTALLATION (Continued)

(1) Install target magnet in end of camshaft.
Tighten mounting screw to 3 N´m (30 in. lbs.) torque.
(2) Install camshaft position sensor. Tighten sensor
mounting screws to 9 N´m (80 in. lbs.) torque.
(3) Carefully attach electrical connector to cam-
shaft position sensor. Installation at an angle may
damage the sensor pins.
(4) Install filtered air tube. Tighten clamps to 3
N´m61 (25 in. lbs.65) torque.
CRANKSHAFT POSITION SENSOR
The crankshaft position sensor mounts to the
engine block behind the generator, just above the oil
filter (Fig. 37).
REMOVAL
(1) Disconnect electrical connector from crankshaft
position sensor.
(2) Remove sensor mounting screw. Remove sensor.
INSTALLATION
Reverse procedure for installation.
COMBINATION ENGINE COOLANT TEMPERATURE
SENSORÐSOHC
The combination engine coolant sensor is located at
the rear of the cylinder head next to the camshaft
position sensor (Fig. 38). New sensors have sealant
applied to the threads.
REMOVAL
(1) With the engine cold, drain the cooling system
until coolant level drops below sensor. Refer to Group
7, Cooling System.
(2) Disconnect coolant sensor electrical connector.
(3) Remove coolant sensor
INSTALLATION
(1) Install coolant sensor. Tighten sensor to 18.6
N´m (165 in. lbs.) torque.
(2) Attach electrical connector to sensor.
(3) Fill cooling system. Refer to Group 7, Cooling
System.
COMBINATION ENGINE COOLANT TEMPERATURE
SENSORÐDOHC
The coolant sensor threads into the intake mani-
fold next to the thermostat housing (Fig. 39). New
sensors have sealant applied to the threads.
REMOVAL
(1) With the engine cold, drain coolant until level
drops below cylinder head. Refer to Group 7, Cooling
System.
(2) Disconnect coolant sensor electrical connector.
(3) Remove coolant sensor.
INSTALLATION
(1) Install coolant sensor. Tighten sensor to 18.6
N´m (165 in. lbs.) torque.
(2) Attach electrical connector to sensor.
(3) Fill cooling system. Refer to Group 7, Cooling
System.
Fig. 36 Target Magnet Installation
Fig. 37 Crankshaft Position Sensor
Fig. 38 Engine Coolant Temperature Sensor
PLIGNITION SYSTEM 8D - 15
REMOVAL AND INSTALLATION (Continued)