key battery DODGE NEON 2000 Service Owner's Guide

BATTERY VOLTAGEÐPCM INPUT
OPERATION
In order for the PCM to operate, it must be sup-
plied with battery voltage and ground. The PCM
monitors the direct battery feed input to determine
battery charging rate and to control the injector ini-
tial opening point. It also has back-up RAM memory
used to store Diagnostic Trouble Codes (supply work-
ing DTCs). Direct battery feed is also used to perform
key-OFF diagnostics and to supply working voltage
to the controller for OBDII.
The five and eight volt regulators are protected
from shorts to ground. This protection allows diag-
nostics to be performed should the five volt power
supply become shorted to ground at any of the sen-
sors. A short to ground in the five volt power supply
will cause a ªno-startº situation. There is a Diagnos-
tic Trouble Code (DTC) if the five-volt power supply
becomes shorted to ground. Refer to the Diagnostic
Procedures Manual for more details on any on-board
diagnostic information.
If battery voltage is low the PCM will increase
injector pulse width (period of time that the injector
is energized).
The direct battery feed to the PCM is used as a
reference point to sense battery voltage.
Effect on Fuel Injectors
Fuel injectors are rated for operation at a specific
voltage. If the voltage increases, the plunger will
open faster and further (more efficient) and con-
versely, if voltage is low the injector will be slow to
open and will not open as far. Therefore, if sensed
battery voltage drops, the PCM increases injector
pulse-width to maintain the same volume of fuel
through the injector.
Charging
The PCM uses sensed battery voltage to verify that
target charging voltage (determined by Battery Tem-
perature Sensor) is being reached. To maintain the
target charging voltage, the PCM will full field the
generator to 0.5 volt above target then turn OFF to
0.5 volt below target. This will continue to occur up
to a 100 Hz frequency, 100 times per second.
BRAKE SWITCHÐPCM INPUT
OPERATION
When the brake switch is activated, the PCM
receives an input indicating that the brakes are
being applied. The brake switch is mounted on the
brake pedal support bracket.
CAMSHAFT POSITION SENSORÐPCM INPUT
DESCRIPTION
The camshaft position sensor attaches to the rear
of the cylinder head. The PCM determines fuel injec-
tion synchronization and cylinder identification from
inputs provided by the camshaft position sensor (Fig.
3) and crankshaft position sensor. From the two
inputs, the PCM determines crankshaft position.
OPERATION
The PCM sends approximately 8 volts to the hall
affect sensor. This voltage is required to operate the
hall effect chip and the electronics inside the sensor.
A ground for the sensor is provided through the sen-
sor return circuit. The input to the PCM occurs on a
5 volt output reference circuit.
A target magnet attaches to the rear of the cam-
shaft and indexes to the correct position. The target
magnet has four different poles arranged in an asym-
metrical pattern (Fig. 4). As the target magnet
rotates, the camshaft position sensor senses the
change in polarity (Fig. 5). The sensor output switch
switches from high (5.0 volts) to low (0.5 volts) as the
target magnet rotates. When the north pole of the
target magnet passes under the sensor, the output
switches high. The sensor output switches low when
the south pole of the target magnet passes under-
neath.
The sensor also acts as a thrust plate to control
camshaft endplay.
Fig. 3 Camshaft Position SensorÐSOHC
14 - 28 FUEL SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

OPERATION
When the knock sensor detects a knock in one of
the cylinders, it sends an input signal to the PCM. In
response, the PCM retards ignition timing for all cyl-
inders by a scheduled amount.
Knock sensors contain a piezoelectric material
which sends an input voltage (signal) to the PCM. As
the intensity of the engine knock vibration increases,
the knock sensor output voltage also increases.
The voltage signal produced by the knock sensor
increases with the amplitude of vibration. The PCM
receives as an input the knock sensor voltage signal.
If the signal rises above a predetermined level, the
PCM will store that value in memory and retard
ignition timing to reduce engine knock. If the knock
sensor voltage exceeds a preset value, the PCM
retards ignition timing for all cylinders. It is not a
selective cylinder retard.
The PCM ignores knock sensor input during engine
idle conditions. Once the engine speed exceeds a
specified value, knock retard is allowed.
Knock retard uses its own short term and long
term memory program.
Long term memory stores previous detonation
information in its battery-backed RAM. The maxi-
mum authority that long term memory has over tim-
ing retard can be calibrated.
Short term memory is allowed to retard timing up
to a preset amount under all operating conditions (as
long as rpm is above the minimum rpm) except WOT.
The PCM, using short term memory, can respond
quickly to retard timing when engine knock is
detected. Short term memory is lost any time the
ignition key is turned off.
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSORÐPCM INPUT
DESCRIPTION
The MAP sensor mounts to the intake manifold
(Fig. 17).
OPERATION
The PCM supplies 5 volts direct current to the
MAP sensor. The MAP sensor converts intake mani-
fold pressure into voltage. The PCM monitors the
MAP sensor output voltage. As vacuum increases,
MAP sensor voltage decreases proportionately. Also,
as vacuum decreases, MAP sensor voltage increases
proportionately.
At key on, before the engine is started, the PCM
determines atmospheric air pressure from the MAP
sensor voltage. While the engine operates, the PCM
determines intake manifold pressure from the MAP
sensor voltage. Based on MAP sensor voltage andinputs from other sensors, the PCM adjusts spark
advance and the air/fuel mixture.
If the PCM considers the MAP Sensor information
inaccurate, the PCM moves into ªlimp-inº mode.
When the MAP Sensor is in limp-in, the PCM limits
the engine speed as a function of the Throttle Posi-
tion Sensor (TPS) to between 1500 and 4000 rpm. If
the MAP Sensor sends realistic signals once again,
the PCM moves out of limp-in and resumes using the
MAP values.
During limp-in a DTC is set and the MIL illumi-
nates.
POWER STEERING PRESSURE SWITCHÐPCM
INPUT
DESCRIPTION
A pressure sensing switch is located on the power
steering gear.
OPERATION
The switch (Fig. 18) provides an input to the PCM
during periods of high pump load and low engine
RPM; such as during parking maneuvers.
When power steering pump pressure exceeds 2758
kPa (400 psi), the switch is open. The PCM increases
idle air flow through the IAC motor to prevent
engine stalling. The PCM sends 12 volts through a
resister to the sensor circuit to ground. When pump
pressure is low, the switch is closed.
SENSOR RETURNÐPCM INPUT
OPERATION
The sensor return circuit provides a low electrical
noise ground reference for all of the systems sensors.
Fig. 17 Manifold Absolute Pressure Sensor
PLFUEL SYSTEM 14 - 35
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)

bolt nut to a torque of 28 N´m (250 in. lbs.). Install
the pinch bolt retainer pin.
(11) Install the upper and lower steering column
shrouds onto the steering column (Fig. 9). Snap the
two shrouds together and then install and tighten
the two screws securing the shrouds to the column.
(12) Install the steering column cover that mounts
below the steering column on the instrument panel
by first aligning the retainer clips and snapping the
cover into place. Install the two screws along the bot-
tom of the steering column cover.
(13) Align the clips along the outer edge of the
instrument cluster bezel with the mounting holes in
the instrument panel and install the bezel.
(14) Align the clips on the bottom of the instru-
ment panel top cover with the mounting holes in the
instrument panel and install the top cover by push-
ing it down into place.
(15) Install the screw securing the left end of the
top cover to the instrument panel.
CAUTION: If there is any question as to whether
the clockspring is in the centered position, the
clock spring needs to be recentered before install-
ing the steering wheel. If the clockspring is not cen-
tered, it may be overextended, causing the
clockspring to become inoperative.
(16) Center the clockspring using the following
procedure:
²Using your fingers, rotate the clockspring rotor
in the CLOCKWISE DIRECTION to the end of the
travel. Do not apply excessive torque.
²From the end of travel, rotate the rotor two full
turns and an additional half turn in the counter-
clockwise direction. (The wires should end up at the
bottom of the clockspring).
CAUTION: Do not install the steering wheel onto
the shaft of the steering column by driving it onto
the shaft.
(17) Feed the clockspring wiring leads through the
hole in the steering wheel (Fig. 6). Align the steering
wheel's wide mounting spline with the steering col-
umn shaft missing spline area and push the wheel
onto the shaft. Make sure the clockspring squares up
with the back of the wheel and does not bind.
(18) Install the steering wheel retaining nut and
tighten it until the steering wheel is fully installed
on shaft. Tighten the steering wheel retaining nut to
a torque of 61 N´m (45 ft. lbs.).
(19) Connect the clockspring electrical leads to the
speed control switches and reinstall the switches on
the steering wheel (Fig. 6).
(20) Install the airbag electrical lead from the
clockspring into the connector on the back of the air-bag module (Fig. 6). Be sure electrical connector from
clockspring is securely latched into airbag module
connector.
(21) Connect the horn switch electrical lead to the
connector on the back of the airbag module (Fig. 6).
CAUTION: The fasteners originally used for the air-
bag components are specifically designed for the
airbag system. They must never be replaced with
any substitutes. Anytime a new fastener is needed,
replace it with only the correct fastener listed in the
parts book.
(22) Install the airbag module into the center of
the steering wheel. Align the airbag module mount-
ing holes with the bolt holes in steering wheel (Fig.
6). Install only the two original or identical replace-
ment airbag module mounting screws. Tighten the
two air bag module attaching bolts to a torque of 10
N´m (90 in. lbs.).
(23) Install the airbag mounting screw trim caps
on the steering wheel rear cover (Fig. 7). One belongs
on each side of the steering wheel.
NOTE: When reconnecting the battery on a vehicle
that has had the airbag module removed, the fol-
lowing procedure should be used.
(24) Reconnect the ground cable to the negative
post of the battery in the following manor:
²Connect a scan tool (DRBIIIt) to the data link
diagnostic connector located below the steering col-
umn.
²Turn the ignition key to the ON position. Exit
the vehicle with the scan tool leaving the scan tool
harness plugged in.
²Ensuring that there are no occupants in the
vehicle, connect the ground (-) cable to the negative
post of the battery.
²Using the scan tool, read and record any fault
codes. Refer to the DRIVER AND PASSENGER AIR-
BAG SYSTEM diagnostic manual if any faults are
found.
²Erase any stored faults if there are no active
fault codes. If a problem exists, the fault code will
not erase.
²Reach around the back of the steering wheel (in
front of the instrument cluster) and turn the ignition
key to OFF, then back ON while observing the
instrument cluster airbag lamp. It should go on for
six to eight seconds, then go out. This will indicate
that the airbag system is functioning normally. If air-
bag warning lamp fails to light, blinks on and off, or
goes on and stays on, there is an airbag system mal-
function. Refer to the BODY DIAGNOSTIC PROCE-
DURES manual to diagnose the system malfunction.
PLSTEERING 19 - 37
REMOVAL AND INSTALLATION (Continued)

(9) Verify that shifter is in gated ªPARKº.
(10) Install the cable core end to the plastic cam of
the shifter mechanism. Snap the shifter/ignition
interlock cable end fitting into the groove in the gear-
shift mechanism as shown in (Fig. 32).
(11)Adjust interlock cable/system as follows:
If interlock cable is being replaced, it will come with
an adjustment pin. Remove the pin from the cable
and allow the cable to ªself-adjustº. Lock cable
adjustment by pressing down on the adjuster lock
until bottomed at the cable housing. If interlock cable
is being re-used, no pin will be provided. Pry up on
cable adjuster lock to release and allow cable to ªself-
adjustº. Lock cable adjustment by pressing down on
the adjuster lock until bottomed at the cable housing.
(12)Connect battery negative cable and ver-
ify interlock system operation as follows:
(13) Install shifter bezel (Fig. 31).
(14) Install center console assembly (Fig. 30).
(15) Install gearshift knob and tighten set screw to
2 N´m (15 in. lbs.) torque (Fig. 29).
INTERLOCK MECHANISM
REMOVAL
(1) Remove the steering column lower cover (Fig.
39).
(2) Remove the steering column upper and lower
shrouds (Fig. 40).
(3) Turn the ignition key to the ªOFFº or ªON/
RUNº position (Fig. 41).
(4) Grasp the interlock cable and connector firmly.
Remove the interlock cable (Fig. 42).(5) Remove the two interlock mechanism-to-steer-
ing column attaching screws (Fig. 43). Remove the
interlock housing.INSTALLATION
(1) Position the interlock housing at steering col-
umn. Install the two interlock mechanism-to-steering
column attaching screws. Torque screws to 3 N´m (21
in. lbs.).
(2) Snap the interlock cable into the housing.
ACTION EXPECTED RESPONSE
1. Turn key to the ªOFFº
position.1. Shifter CAN be shifted
out of park.
2. Turn key to the
9ON/RUNº position.2. Shifter CANNOT be
shifted out of park.
3. Turn key to the
ªON/RUNº position and
depress the brake pedal.3. Shifter CAN be shifted
out of park.
4. Leave shifter in any
gear and try to return key
to the ªLOCKº or9ACCº
position.4. Key cannot be
returned to the ªLOCKº or
ªACCº position.
5. Return shifter to
ªPARKº and try to remove
the key.5. Key can be removed
(after returning to ªLOCKº
position).
6. With the key removed,
try to shift out of ªPARKº.6. Shifter cannot be
shifted out of ªPARKº.
NOTE: Any failure to meet these expected
responses requires system adjustment or repair.
Fig. 39 Steering Column Lower Cover
1 ± LOWER COVER
Fig. 40 Steering Column Shrouds
1 ± UPPER SHROUD
2 ± LOWER SHROUD
21 - 82 TRANSAXLEPL
REMOVAL AND INSTALLATION (Continued)

(M) Check Engine Lamp (MIL) will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
P1684 The battery has been disconnected within the last 50
starts.
P1685 Skim Invalid Key The engine controler has received an invalid key from
the SKIM.
P1686 No SKIM BUS Messages Received No CCD/J1850 messages received from the Smart Key
Immobilizer Module (SKIM).
P1687 No MIC BUS Message No CCD/J1850 messages received from the Mechanical
Instrument Cluster (MIC) module.
P1693 DTC Detected in Companion
ModuleA fault has been generated in the companion engine
control module.
P1694 Fault In Companion Module No CCD/J1850 messages received from the powertrain
control module-Aisin transmission.
P1695 No CCD/J1850 Message From
Body Control ModuleNo CCD/J1850 messages received from the body
control module.
P1696 (M) PCM Failure EEPROM Write
DeniedUnsuccessful attempt to write to an EEPROM location
by the control module.
P1697 (M) PCM Failure SRI Mile Not Stored Unsuccessful attempt to update Service Reminder
Indicator (SRI or EMR) mileage in the control module
EEPROM.
P1698 (M) No CCD/J1850 Message From TCM No CCD/J1850 messages received from the electronic
transmission control module (EATX) or the Aisin
transmission controller.
P1719 Skip Shift Solenoid Circuit An open or shorted condition detected in the
transmission 2-3 gear lock-out solenoid control circuit.
P1756 GOV Press Not Equal to Target @
15-20 PSIThe requested pressure and the actual pressure are not
within a tolerance band for the Governor Control
System which is used to regulate governor pressure to
control shifts for 1st, 2nd, and 3rd gear. (Mid Pressure
Malfunction)
P1757 GOV Press Not Equal to Target @
15-20 PSIThe requested pressure and the actual pressure are not
within a tolerance band for the Governor Control
System which is used to regulate governor pressure to
control shifts for 1st, 2nd, and 3rd gear (Zero Pressure
Malfunction)
P1762 Gov Press Sen Offset Volts Too Lo
or HighThe Governor Pressure Sensor input is greater than a
calibration limit or is less than a calibration limit for 3
consecutive park/neutral calibrations.
P1763 Governor Pressure Sensor Volts
To o H iThe Governor Pressure Sensor input is above an
acceptable voltage level.
P1764 Governor Pressure Sensor Volts
Too LowThe Governor Pressure Sensor input is below an
acceptable voltage level.
P1765 Trans 12 Volt Supply Relay CTRL
CircuitAn open or shorted condition is detected in the
Transmission Relay control circuit. This relay supplies
power to the TCC>
P1899 (M) P/N Switch Stuck in Park or in Gear Incorrect input state detected for the Park/Neutral
switch.
25 - 14 EMISSION CONTROL SYSTEMSPL
DESCRIPTION AND OPERATION (Continued)

from memory after 40 consecutive warm-up cycles
without test failure.
Enabling ConditionsÐThe following conditions
must typically be met for the PCM to run the oxygen
sensor monitor:
²Battery voltage
²Engine temperature
²Engine run time
²Engine run time at a predetermined speed
²Engine run time at a predetermined speed and
throttle opening
²Transmission in gear (automatic only)
²Fuel system in Closed Loop
²Long Term Adaptive (within parameters)
²Power Steering Switch in low PSI (no load)
²Engine at idle
²Fuel level above 15%
²Ambient air temperature
²Barometric pressure
²Engine RPM within acceptable range of desired
idle
²Closed throttle speed
Pending ConditionsÐThe Task Manager typi-
cally does not run the Oxygen Sensor Monitor if over-
lapping monitors are running or the MIL is
illuminated for any of the following:
²Misfire Monitor
²Front Oxygen Sensor and Heater Monitor
²MAP Sensor
²Vehicle Speed Sensor
²Engine Coolant Temperature Sensor
²Throttle Position Sensor
²Engine Controller Self Test Faults
²Cam or Crank Sensor
²Injector and Coil
²Idle Air Control Motor
²EVAP Electrical
²EGR Solenoid Electrical
²Intake Air Temperature
²5 Volt Feed
ConflictÐThe Task Manager does not run the
Oxygen Sensor Monitor if any of the following condi-
tions are present:
²A/C ON (A/C clutch cycling temporarily sus-
pends monitor)
²Purge flow in progress
SuspendÐThe Task Manager suspends maturing
a fault for the Oxygen Sensor Monitor if an of the fol-
lowing are present:
²Oxygen Sensor Heater Monitor, Priority 1
²Misfire Monitor, Priority 2
OXYGEN SENSOR HEATER MONITOR
DESCRIPTIONÐIf there is an oxygen sensor
(O2S) DTC as well as a O2S heater DTC, the O2S
fault MUST be repaired first. After the O2S fault isrepaired, verify that the heater circuit is operating
correctly.
The voltage readings taken from the O2S are very
temperature sensitive. The readings are not accurate
below 300ÉC. Heating of the O2S is done to allow the
engine controller to shift to closed loop control as
soon as possible. The heating element used to heat
the O2S must be tested to ensure that it is heating
the sensor properly.
The heater element itself is not tested. The sensor
output is used to test the heater by isolating the
effect of the heater element on the O2S output volt-
age from the other effects. The resistance is normally
between 100 ohms and 4.5 megaohms. When oxygen
sensor temperature increases, the resistance in the
internal circuit decreases. The PCM sends a 5 volts
biased signal through the oxygen sensors to ground
this monitoring circuit. As the temperature increases,
resistance decreases and the PCM detects a lower
voltage at the reference signal. Inversely, as the tem-
perature decreases, the resistance increases and the
PCM detects a higher voltage at the reference signal.
an The O2S circuit is monitored for a drop in voltage.
OPERATIONÐThe Oxygen Sensor Heater Moni-
tor begins after the ignition has been turned OFF
and the O2 sensors have cooled. The PCM sends a 5
volt bias to the oxygen sensor every 1.6 seconds. The
PCM keeps it biased for 35 ms each time. As the sen-
sor cools down, the resistance increases and the PCM
reads the increase in voltage. Once voltage has
increased to a predetermined amount, higher than
when the test started, the oxygen sensor is cool
enough to test heater operation.
When the oxygen sensor is cool enough, the PCM
energizes the ASD relay. Voltage to the O2 sensor
begins to increase the temperature. As the sensor
temperature increases, the internal resistance
decreases. The PCM continues biasing the 5 volt sig-
nal to the sensor. Each time the signal is biased, the
PCM reads a voltage decrease. When the PCM
detects a voltage decrease of a predetermined value
for several biased pulses, the test passes.
The heater elements are tested each time the
engine is turned OFF if all the enabling conditions
are met. If the monitor fails, the PCM stores a
maturing fault and a Freeze Frame is entered. If two
consecutive tests fail, a DTC is stored. Because the
ignition is OFF, the MIL is illuminated at the begin-
ning of the next key cycle.
Enabling ConditionsÐThe following conditions
must be met for the PCM to run the oxygen sensor
heater test:
²Engine run time of at least 5.1 minutes
²Key OFF power down
²Battery voltage of at least 10 volts
²Sufficient Oxygen Sensor cool down
PLEMISSION CONTROL SYSTEMS 25 - 21
DESCRIPTION AND OPERATION (Continued)