2000 DODGE NEON spark

DATA LINK CONNECTOR
DESCRIPTION
The data link connector is located inside the vehi-
cle, under the instrument panel, left of the steering
column (Fig. 25).
OPERATION
The data link connector (diagnostic connector)
links the DRB scan tool with the powertrain control
module (PCM). Refer to On-Board Diagnostics in the
General Diagnosis section of this group.
FUEL INJECTORSÐPCM OUTPUT
DESCRIPTION
OPERATION
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
DESCRIPTION
The coil assembly consists of 2 coils molded
together. The coil assembly is mounted over the valve
cover (Fig. 27).
OPERATION
High tension leads route to each cylinder from the
coil. The coil fires two spark plugs every power
Fig. 24 Idle Air Control MotorÐTypical
Fig. 25 Data Link Connector
1 ± DATA LINK CONNECTOR
Fig. 26 Fuel Injector
1 ± FUEL INJECTOR
2 ± NOZZLE
3 ± TOP (FUEL ENTRY)
14 - 40 FUEL SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

stroke. One plug is the cylinder 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 and
camshaft position sensor inputs. Refer to Auto Shut-
down (ASD) RelayÐPCM Output in this section for
relay operation.
Base timing is non-adjustable, but is set from the
factory at approximately 10ÉBTDC when the engine
is warm and idling.
There is an adaptive dwell strategy that runs dwell
from 4 to 6 msec when rpm is below 3,000 and bat-
tery voltage is 12-14 volts. During cranking, dwell
can be as much as 200 msec. The adaptive dwell is
driven by the sensed current flow through the injec-
tor drivers. Current flow is limited to 8 amps.
The low resistance of the primary coils can allow
current flow in excess of 15 amps. The PCM has a
current sensing device in the coil output circuit. As
dwell time starts, the PCM allows current to flow.
When the sensing device registers 8 amps, the PCM
begins to regulate current flow to maintain and not
exceed 8 amps through the remainder of the dwell
time. This prevents the PCM from being damaged by
excess current flow.
MALFUNCTION INDICATOR (CHECK ENGINE)
LAMPÐPCM OUTPUT
OPERATION
The PCM supplies the malfunction indicator (check
engine) lamp on/off signal to the instrument panel
through the PCI Bus. The PCI Bus is a communica-
tions port. Various modules use the PCI 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
send incorrect signals. The PCM substitutes for the
incorrect signals with inputs from other sensors.
If the PCM detects active engine misfire severe
enough to cause catalyst damage, it flashes the MIL.
At the same time the PCM also sets a Diagnostic
Trouble Code (DTC).
For signals that can trigger the MIL (Check
Engine Lamp) refer to the On-Board Diagnos-
tics section.
SPEED CONTROLÐPCM INPUT
OPERATION
The speed control system provides five separate
voltages (inputs) to the Powertrain Control Module
(PCM). The voltages correspond to the ON, OFF,
SET, RESUME, CANCEL, and COAST.
The speed control ON voltage informs the PCM
that the speed control system has been activated.
The speed control SET voltage informs the PCM that
a fixed vehicle speed has been selected. The speed
control RESUME voltage indicates the previous fixed
speed is requested. The speed control CANCEL volt-
age tells the PCM to deactivate but retain set speed
in memory (same as depressing the brake pedal). The
speed control COAST voltage informs the PCM to
coast down to a new desired speed. The speed control
OFF voltage tells the PCM that the speed control
system has deactivated. Refer to the Speed Control
section for more speed control information.
SCI RECEIVEÐPCM OUTPUT
OPERATION
SCI Receive is the serial data communication
receive circuit for the DRB scan tool. The Powertrain
Fig. 27 Ignition Coil Pack
PLFUEL SYSTEM 14 - 41
DESCRIPTION AND OPERATION (Continued)

(3) Lift the sensor out of the transaxle extension
housing. Ensure the O-ring was removed with the
sensor.
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
The sensors screws into the cylinder block.
REMOVAL
(1) Raise vehicle on hoist and support.
(2) Disconnect electrical connector from knock sen-
sor (Fig. 50).
(3) Use a crows foot socket to remove the knock
sensors.
INSTALLATION
(1) Install knock sensor. Tighten knock sensor to
10 N´m (7 ft. lbs.) torque.Over or under tighten-
ing effects knock sensor performance resulting
in possible improper spark control.
(2) Attach electrical connector to knock sensor.
(3) Lower vehicle.
Fig. 47 Engine Coolant Temperature Sensor
1 ± ENGINE COOLANT TEMPERATURE SENSOR
2 ± CAMSHAFT POSITION SENSOR
Fig. 48 Vehicle Speed Sensor Manual
1 ± TRANSAXLE
2 ± SPEED SENSOR
3 ± SPEED SENSOR RETAINING BOLT
Fig. 49 Vehicle Speed Sensor Automatic
1 ± TRANSAXLE EXTENSION HOUSING
2 ± VEHICLE SPEED SENSOR
Fig. 50 Knock Sensor Location
14 - 48 FUEL SYSTEMPL
REMOVAL AND INSTALLATION (Continued)

FLUSHING COOLERS AND TUBES
When a transaxle failure has contaminated the
fluid, the transaxle oil cooler(s) must be flushed (both
radiator and remote). The cooler bypass valve in the
transaxle must be replaced also. The torque con-
verter must also be replaced with an exchange unit.
This will ensure that metal particles or sludged oil
are not later transferred back into the reconditioned
(or replaced) transaxle.
The recommended procedure for flushing the cool-
ers and tubes is to use Tool 6906A Cooler Flusher.
WARNING: WEAR PROTECTIVE EYEWEAR THAT
MEETS THE REQUIREMENTS OF OSHA AND ANSI
Z87.1±1968. WEAR STANDARD INDUSTRIAL RUB-
BER GLOVES.
KEEP LIT CIGARETTES, SPARKS, FLAMES, AND
OTHER IGNITION SOURCES AWAY FROM THE
AREA TO PREVENT THE IGNITION OF COMBUSTI-
BLE LIQUIDS AND GASES. KEEP A CLASS (B) FIRE
EXTINGUISHER IN THE AREA WHERE THE
FLUSHER WILL BE USED.
KEEP THE AREA WELL VENTILATED.
DO NOT LET FLUSHING SOLVENT COME IN CON-
TACT WITH YOUR EYES OR SKIN: IF EYE CONTAM-
INATION OCCURS, FLUSH EYES WITH WATER FOR
15 TO 20 SECONDS. REMOVE CONTAMINATED
CLOTHING AND WASH AFFECTED SKIN WITH
SOAP AND WATER. SEEK MEDICAL ATTENTION.
COOLER FLUSH USING TOOL 6906A
(1) Remove cover plate filler plug on Tool 6906A.
Fill reservoir 1/2 to 3/4 full of fresh flushing solution.
Flushing solvents are petroleum based solutions gen-
erally used to clean automatic transmission compo-
nents.DO NOTuse solvents containing acids, water,
gasoline, or any other corrosive liquids.
(2) Reinstall filler plug on Tool 6906A.
(3) Verify pump power switch is turned OFF. Con-
nect red alligator clip to positive (+) battery post.
Connect black (-) alligator clip to a good ground.
(4) Disconnect the cooler lines at the transmission.
NOTE: When flushing transmission cooler and
lines, ALWAYS reverse flush.
(5) Connect the BLUE pressure line to the OUT-
LET (From) cooler line.
(6) Connect the CLEAR return line to the INLET
(To) cooler line
(7) Turn pump ON for two to three minutes to
flush cooler(s) and lines. Monitor pressure readingsand clear return lines. Pressure readings should sta-
bilize below 20 psi. for vehicles equipped with a sin-
gle cooler and 30 psi. for vehicles equipped with dual
coolers. If flow is intermittent or exceeds these pres-
sures, replace cooler.
(8) Turn pump OFF.
(9) Disconnect CLEAR suction line from reservoir
at cover plate. Disconnect CLEAR return line at
cover plate, and place it in a drain pan.
(10) Turn pump ON for 30 seconds to purge flush-
ing solution from cooler and lines. Turn pump OFF.
(11) Place CLEAR suction line into a one quart
container of MopartATF+4 (Automatic Transmission
Fluid) Type 9602.
(12) Turn pump ON until all transmission fluid is
removed from the one quart container and lines. This
purges any residual cleaning solvent from the trans-
mission cooler and lines. Turn pump OFF.
(13) Disconnect alligator clips from battery. Recon-
nect flusher lines to cover plate, and remove flushing
adapters from cooler lines.
OIL PUMP VOLUME CHECK
After the new or repaired transmission has been
installed, fill to the proper level with MopartATF+4
(Automatic Transmission Fluid) Type 9602. The vol-
ume should be checked using the following proce-
dure:
(1) Disconnect theFrom coolerline at the trans-
mission and place a collecting container under the
disconnected line.
CAUTION: With the fluid set at the proper level,
fluid collection should not exceed (1) quart or inter-
nal damage to the transmission may occur.
(2) Run the engineat curb idle speed, with the
shift selector in neutral.
(3) If fluid flow is intermittent or it takes more
than 20 seconds to collect one quart of ATF, discon-
nect theTo Coolerline at the transaxle.
(4) Refill the transaxle to proper level and recheck
pump volume.
(5) If flow is found to be within acceptable limits,
replace the cooler. Then fill transmission to the
proper level, using MopartATF+4 (Automatic Trans-
mission Fluid) Type 9602.
(6) If fluid flow is still found to be inadequate,
check the line pressure using the Transaxle Hydrau-
lic Pressure Test procedure.
21 - 72 TRANSAXLEPL
SERVICE PROCEDURES (Continued)

PCM). Because the condition happens at an engine
speed above the maximum threshold (2000 rpm), the
PCM will not store a DTC.
There are several operating conditions for which
the PCM monitors and sets DTC's. Refer to Moni-
tored Systems, Components, and Non-Monitored Cir-
cuits in this section.
NOTE: Various diagnostic procedures may actually
cause a diagnostic monitor to set a DTC. For
instance, pulling a spark plug wire to perform a
spark test may set the misfire code. When a repair
is completed and verified, use the DRB III scan tool
to erase all DTC's and extinguish the MIL.
Technicians can display stored DTC's by using the
DRB III scan tool. Refer to Diagnostic Trouble Codes
in this section. For DTC information, refer to charts
in this section.
TASK MANAGER
DESCRIPTION
The PCM is responsible for efficiently coordinating
the operation of all the emissions-related compo-
nents. The PCM is also responsible for determining if
the diagnostic systems are operating properly. The
software designed to carry out these responsibilities
is call the 'Task Manager'.
OPERATION
The Task Manager determines which tests happen
when and which functions occur when. Many of the
diagnostic steps required by OBD II must be per-
formed under specific operating conditions. The Task
Manager software organizes and prioritizes the diag-
nostic procedures. The job of the Task Manager is to
determine if conditions are appropriate for tests to berun, monitor the parameters for a trip for each test,
and record the results of the test. Following are the
responsibilities of the Task Manager software:
²Test Sequence
²MIL Illumination
²Diagnostic Trouble Codes (DTCs)
²Trip Indicator
²Freeze Frame Data Storage
²Similar Conditions Window
Test Sequence
In many instances, emissions systems must fail
diagnostic tests more than once before the PCM illu-
minates the MIL. These tests are know as 'two trip
monitors.' Other tests that turn the MIL lamp on
after a single failure are known as 'one trip moni-
tors.' A trip is defined as 'start the vehicle and oper-
ate it to meet the criteria necessary to run the given
monitor.'
Many of the diagnostic tests must be performed
under certain operating conditions. However, there
are times when tests cannot be run because another
test is in progress (conflict), another test has failed
(pending) or the Task Manager has set a fault that
may cause a failure of the test (suspend).
²Pending
Under some situations the Task Manager will not
run a monitor if the MIL is illuminated and a fault is
stored from another monitor. In these situations, the
Task Manager postpones monitorspendingresolu-
tion of the original fault. The Task Manager does not
run the test until the problem is remedied.
For example, when the MIL is illuminated for an
Oxygen Sensor fault, the Task Manager does not run
the Catalyst Monitor until the Oxygen Sensor fault is
remedied. Since the Catalyst Monitor is based on sig-
nals from the Oxygen Sensor, running the test would
produce inaccurate results.
²Conflict
There are situations when the Task Manager does
not run a test if another monitor is in progress. In
these situations, the effects of another monitor run-
ning could result in an erroneous failure. If thiscon-
flictis present, the monitor is not run until the
conflicting condition passes. Most likely the monitor
will run later after the conflicting monitor has
passed.
For example, if the Fuel System Monitor is in
progress, the Task Manager does not run the EGR
Monitor. Since both tests monitor changes in air/fuel
ratio and adaptive fuel compensation, the monitors
will conflict with each other.
²Suspend
Occasionally the Task Manager may not allow a two
trip fault to mature. The Task Manager willsus-
pendthe maturing of a fault if a condition exists
Fig. 1 Data Link (Diagnostic) Connector
1 ± DIAGNOSTIC CONNECTOR
25 - 2 EMISSION CONTROL SYSTEMSPL
DESCRIPTION AND OPERATION (Continued)

Pending ConditionsÐ
²Misfire DTC
²Front Oxygen Sensor Response
²Front Oxygen Sensor Heater Monitor
²Front Oxygen Sensor Electrical
²Rear Oxygen Sensor Rationality (middle check)
²Rear Oxygen Sensor Heater Monitor
²Rear Oxygen Sensor Electrical
²Fuel System Monitor
²All TPS faults
²All MAP faults
²All ECT sensor faults
²Purge flow solenoid functionality
²Purge flow solenoid electrical
²All PCM self test faults
²All CMP and CKP sensor faults
²All injector and ignition electrical faults
²Idle Air Control (IAC) motor functionality
²Vehicle Speed Sensor
²Brake switch
²Intake air temperature
ConflictÐThe catalyst monitor does not run if
any of the following are conditions are present:
²EGR Monitor in progress
²Fuel system rich intrusive test in progress
²EVAP Monitor in progress
²Time since start is less than 60 seconds
²Low fuel level
²Low ambient air temperature
SuspendÐThe Task Manager does not mature a
catalyst fault if any of the following are present:
²Oxygen Sensor Monitor, Priority 1
²Upstream Oxygen Sensor Heater, Priority 1
²EGR Monitor, Priority 1
²EVAP Monitor, Priority 1
²Fuel System Monitor, Priority 2
²Misfire Monitor, Priority 2
NON-MONITORED CIRCUITS
OPERATION
The PCM does not monitor all circuits, systems
and conditions that could have malfunctions causing
driveability problems. However, problems with these
systems may cause the PCM to store diagnostic trou-
ble codes for other systems or components. For exam-
ple, a fuel pressure problem will not register a fault
directly, but could cause a rich/lean condition or mis-
fire. This could cause the PCM to store an oxygen
sensor or misfire diagnostic trouble code.
The major non-monitored circuits are listed below
along with examples of failures modes that do not
directly cause the PCM to set a DTC, but for a sys-
tem that is monitored.FUEL PRESSURE
The fuel pressure regulator controls fuel system
pressure. The PCM cannot detect a clogged fuel
pump inlet filter, clogged in-line fuel filter, or a
pinched fuel supply or return line. However, these
could result in a rich or lean condition causing the
PCM to store an oxygen sensor or fuel system diag-
nostic trouble code.
SECONDARY IGNITION CIRCUIT
The PCM cannot detect an inoperative ignition coil,
fouled or worn spark plugs, ignition cross firing, or
open spark plug cables.
CYLINDER COMPRESSION
The PCM cannot detect uneven, low, or high engine
cylinder compression.
EXHAUST SYSTEM
The PCM cannot detect a plugged, restricted or
leaking exhaust system. It may set a EGR or Fuel
system fault or O2S.
FUEL INJECTOR MECHANICAL MALFUNCTIONS
The PCM cannot determine if a fuel injector is
clogged, the needle is sticking or if the wrong injector
is installed. However, these could result in a rich or
lean condition causing the PCM to store a diagnostic
trouble code for either misfire, an oxygen sensor, or
the fuel system.
EXCESSIVE OIL CONSUMPTION
Although the PCM monitors engine exhaust oxygen
content when the system is in closed loop, it cannot
determine excessive oil consumption.
THROTTLE BODY AIR FLOW
The PCM cannot detect a clogged or restricted air
cleaner inlet or filter element.
VACUUM ASSIST
The PCM cannot detect leaks or restrictions in the
vacuum circuits of vacuum assisted engine control
system devices. However, these could cause the PCM
to store a MAP sensor diagnostic trouble code and
cause a high idle condition.
PCM SYSTEM GROUND
The PCM cannot determine a poor system ground.
However, one or more diagnostic trouble codes may
be generated as a result of this condition. The mod-
ule should be mounted to the body at all times, also
during diagnostic.
PLEMISSION CONTROL SYSTEMS 25 - 23
DESCRIPTION AND OPERATION (Continued)