electrical DODGE NEON 2000 Service Repair Manual

(g) Install the ignition key cylinder in the steer-
ing column. To do this, first position the key cylin-
der in the ON position (with the key in it) so the
retaining tab can be depressed. Push key cylinder
into the column ignition cylinder housing until the
retaining tab locks into place (Fig. 16).
NOTE: When installing a tilt column, do not release
the tilt lever from the locked position until after the
column is installed on the instrument panel.
(2) Install the steering column into steering col-
umn access opening in the lower instrument panel.
(3) If the vehicle is equipped with a SKIM, Con-
nect its wiring harness electrical connector (Fig. 15).(4) Connect the wiring harness electrical connec-
tors to the multi-function switch, windshield wiper
switch, and ignition switch (Fig. 14).
(5) Connect the wiring harness electrical connector
to the clockspring (Fig. 13).
(6) Align the slots in the mounting brackets on the
steering column with the studs in the instrument
panel (Fig. 12) Attach the column to the instrument
panel by first installing the two upper mounting nuts
(Do not completely tighten the two upper mounting
nuts at this time). Next, install the two lower mount-
ing nuts. Tighten all four mounting nuts to a torque
of 17 N´m (150 in. lbs.).
(7) If the vehicle is equipped with an automatic
transaxle, connect the automatic transaxle ignition
interlock cable to the steering column by pushing the
end of the cable into the back side of the ignition cyl-
inder housing until it snaps into place (Fig. 11).
(8) Position the steering column shaft in the cor-
rect position for mounting to the lower coupling. To
do this, turn the steering wheel end of the shaft until
the missing spline area on that end of the shaft faces
straight up.
(9) Verify the front wheels of vehicle are in the
STRAIGHT-AHEAD position.
NOTE: Do not tighten the coupling pinch bolt any-
time the vehicle is not at curb riding height. It may
cause unwanted conditions within the steering col-
umn if the vehicle is suspended in any manner
when the pinch bolt is tightened.
(10) Reconnect the steering column lower coupling
to the steering column upper coupling (Fig. 10).
Install the coupling pinch bolt an tighten the pinch
Fig. 18 Multi-function/Wiper Switch Mounting
1 ± MOUNTING SCREWS
2 ± MULTI-FUNCTION/WINDSHIELD WIPER SWITCH ASSEMBLY
Fig. 19 SKIM Mounting
1 ± HALO TRIM RING
2 ± MOUNTING SCREWS
3 ± SKIM
Fig. 20 Ignition Switch Mounting
1 ± MOUNTING SCREW
2 ± IGNITION SWITCH
19 - 36 STEERINGPL
REMOVAL AND INSTALLATION (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)

(23) Carefully lower engine and transaxle on screw
jack until proper removal clearance is obtained.
(24) Obtain a helper to assist in holding transaxle
while removing transaxle-to-engine mounting bolts
(Fig. 44).(25) Remove transaxle from vehicle (Fig. 44).
(26) If installing a new or replacement transaxle,
remove the upper mount as shown in (Fig. 45), trans-
fer to the replacement unit and torque all bolts to 68
N´m (50 ft. lbs.) torque.
INSTALLATION
(1) Install clutch module onto input shaft. Install
transaxle into position.
(2) Install transaxle-to-engine mounting bolts (Fig.
44) and tighten to 95 N´m (70 ft. lbs.) torque.
(3) Raise engine and transaxle with screw jack
until through hole in upper mount aligns with hole
in mount bracket. Install mount bolt and tighten to
108 N´m (80 ft. lbs.) torque (Fig. 43).
(4) Remove screwjack.
(5) Install drive plate-to-clutch module bolts and
torque to 88 N´m (65 ft. lbs.) torque.
(6) Install starter motor and tighten bolts to 54
N´m (40 ft. lbs.) torque. Make sure to fasten ground
cable to upper starter bolt as shown in (Fig. 42).
(7) Connect starter electrical harness and tighten
positive cable nut to 10 N´m (90 in. lbs.) torque.
(8) Install bellhousing dust cover (Fig. 40).
(9) Install left engine-to-transaxle bending brace
(Fig. 40).
(10) Install structural collar (Fig. 40) as follows:
(a) Position collar and install all bolts finger
tight.
(b) Tighten the collar-to-oil pan bolts to 3 N´m
(30 in. lbs.) torque.
(c) Tighten the collar-to-transaxle bolts to 108
N´m (80 ft. lbs.) torque.
(d) Final torque the collar-to-oil pan bolts to 54
N´m (40 ft. lbs.) torque.
(11) Install the right lateral bending brace and
tighten bolts to 81 N´m (60 ft. lbs.) torque (Fig. 41).
(12) Install both front axle driveshafts. Refer to
Group 3, Differential and Driveline for the correct
procedures.
(13) Fill transaxle with suitable amount of Mopart
Manual Transaxle Lubricant (PN 04874465).
(14) Lower vehicle.
(15) Connect vehicle speed sensor connector (Fig.
39).
(16) Connect shift crossover and selector cables to
shift lever. Install cables to bracket and install
retaining clips (Fig. 38).
(17) Connect clutch cable to fork and secure to
transaxle (Fig. 37).
(18) Install bellhousing cap (Fig. 37).
(19) Connect back-up lamp switch connector.
(20) Connect ground strap to transaxle upper
mount bracket.
(21) Install battery lower tray and battery, and
tighten battery hold down clamp to secure battery.
Fig. 42 Starter Motor Removal/InstallationÐTypical
1 ± BOLT
2 ± GROUND
3±STARTER
4 ± BOLT
Fig. 43 Transaxle Upper Mount Thru-BoltÐTypical
1 ± MOUNT BRACKET
2 ± BOLT
3 ± MOUNT
21 - 16 TRANSAXLEPL
REMOVAL AND INSTALLATION (Continued)

The kickdown valve makes possible a forced down-
shift from third to second, second to first, or third to
first (depending on vehicle speed). This can be done
by depressing the accelerator pedal past the detent
feel near wide open throttle.
The shuttle valve has two separate functions and
performs each independently of the other. The first is
providing fast release of the kickdown band, and
smooth front clutch engagement when a lift-foot
upshift from second to third is made. The second
function is to regulate the application of the kick-
down servo and band when making third±to±second
kickdown.
The bypass valve provides for smooth application
of the kickdown band on 1-2 upshifts.
The torque converter clutch solenoid allows for the
electronic control of the torque converter clutch. It
also disengages the torque converter at closed throt-
tle. This is done during engine warm-up and part-
throttle acceleration.
The switch valve directs oil to apply the torque
converter clutch in one position. The switch valve
releases the torque converter clutch in the other posi-
tion.
CLUTCHES, BAND SERVOS, AND
ACCUMULATOR
The front and rear clutch pistons, and both servo
pistons, are moved hydraulically to engage the
clutches and apply the bands. The pistons are
released by spring tension when hydraulic pressure
is released. On the 2-3 upshift, the kickdown servo
piston is released by spring tension and hydraulic
pressure.
The accumulator controls the hydraulic pressure
on the apply±side of the kickdown servo during the
1-2 upshift; thereby cushioning the kickdown band
application at any throttle position.
BRAKE TRANSMISSION SHIFT INTERLOCK
SYSTEM
The Brake Transmission Shifter/Ignition Interlock
(BTSI) is a cable and solenoid operated system. It
interconnects the automatic transmission floor
mounted shifter to the steering column ignition
switch. The system locks the shifter into the PARK
position. The interlock system is engaged whenever
the ignition switch is in the LOCK or ACCESSORY
position. An additional electrically activated feature
will prevent shifting out of the PARK position unless
the brake pedal is depressed at least one-half inch. A
magnetic holding device integral to the interlock
cable is energized when the ignition is in the RUN
position. When the key is in the RUN position and
the brake pedal is depressed, the shifter is unlocked
and will move into any position. The interlock systemalso prevents the ignition switch from being turned
to the LOCK or ACCESSORY position, unless the
shifter is in the gated PARK position.
The following chart describes the normal operation
of the Brake Transmission Shift Interlock (BTSI) sys-
tem. If the ªexpected responseº differs from the vehi-
cle's response, then system repair and/or adjustment
is necessary.
GEARSHIFT AND PARKING LOCK CONTROLS
The transaxle is controlled by alever typegear-
shift incorporated within the console. The control has
six selector lever positions: P (Park), R (Reverse), N
(Neutral), and D (Drive), 2 (Second), and 1 (First).
The parking lock is applied by moving the selector
lever past a gate to the (P) position.Do not apply
the parking lock until the vehicle has stopped;
otherwise, a severe banging noise will occur.
COOLER BYPASS VALVE
Some 31TH transaxles are equipped with a cooler
bypass valve (Fig. 2). The valve is designed to bypass
the transaxle oil cooler circuit in cold weather condi-
tions, or when circuit restriction exceeds 25±30 p.s.i.
The valve consists of an integrated check ball and
spring, and a return tube to carry bypassed oil back
to the pump. The bypass valve is mounted to the
valve body transfer plate and is sealed with a rubber
o-ring seal (Fig. 3).
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.
PLTRANSAXLE 21 - 57
DESCRIPTION AND OPERATION (Continued)

INSTALLATION
(1) Install torque converter into front pump.
Rotate converter until the hub fully engages front
pump gear lugs.
(2) Install transaxle-to-engine mounting bolts (Fig.
54) and tighten to 95 N´m (70 ft. lbs.) torque.
(3) Raise engine and transaxle with screw jack
until through hole in upper mount aligns with hole
in mount bracket. Install mount bolt and tighten to
108 N´m (80 ft. lbs.) torque (Fig. 53).
(4) Remove screwjack.
(5) Install converter-to-drive plate bolts and torque
to 88 N´m (65 ft. lbs.) torque.
(6) Install starter motor and tighten bolts to 54
N´m (40 ft. lbs.) torque. Make sure to fasten ground
cable to upper starter bolt as shown in (Fig. 52).
(7) Connect starter electrical harness and tighten
positive cable nut to 10 N´m (90 in. lbs.) torque.
(8) Install bellhousing dust cover (Fig. 51).
(9) Install left engine-to-transaxle bending brace
(Fig. 51).
(10) Install structural collar (Fig. 51) as follows:
(a) Position collar and install all bolts finger
tight.
(b) Tighten the collar-to-oil pan bolts to 3 N´m
(30 in. lbs.) torque.
Fig. 54 Transaxle Removal/Installation
1 ± CLIP
2 ± BOLT (3)3 ± TRANSAXLE
4 ± CONVERTER BOLT (4)
Fig. 55 Transaxle Upper Mount and Bracket
1 ± MOUNT
2 ± TRANSAXLE
PLTRANSAXLE 21 - 87
REMOVAL AND INSTALLATION (Continued)

(M) Check Engine Lamp (MIL) will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
P0740 (M) Torq Con Clu, No RPM Drop at
LockupRelationship between engine and vehicle speeds
indicated failure of torque convertor clutch lock-up
system (TCC/PTU sol).
P0743 Torque Converter Clutch Solenoid/
Trans Relay CircuitsAn open or shorted condition detected in the torque
converter clutch (part throttle unlock) solenoid control
circuit. Shift solenoid C electrical fault - Aisin
transmission
P0748 Governor Pressur Sol Control/Trans
Relay CircuitsAn open or shorted condition detected in the Governor
Pressure Solenoid circuit or Trans Relay Circuit in JTEC
RE transmissions.
P0751 O/D Switch Pressed (Lo) More
Than 5 MinutesOverdrive override switch input is in a prolonged
depressed state.
P0753 Trans 3-4 Shift Sol/Trans Relay
CircuitsAn open or shorted condition detected in the overdrive
solenoid control circuit or Trans Relay Circuit in JTEC
RE transmissions.
P0756 AW4 Shift Sol B (2-3) Functional
FailureShift solenoid B (2-3) functional fault - Aisin
transmission
P0783 3-4 Shift Sol, No RPM Drop at
LockupThe overdrive solenoid is unable to engage the gear
change from 3rd gear to the overdrive gear.
P0801 Reverse Gear Lockout Circuit Open
or ShortAn open or shorted condition detected in the
transmission reverse gear lock-out solenoid control
circuit.
P01192 Inlet Air Temp. Circuit Low Inlet Air Temp. sensor input below acceptable voltage
P01193 Inlet Air Temp. Circuit High Inlet Air Temp. sensor input above acceptable voltage.
P1195 (M) 1/1 O2 Sensor Slow During Catalyst
MonitorA slow switching oxygen sensor has been detected in
bank 1/1 during catalyst monitor test. (was P0133)
P1196 (M) 2/1 O2 Sensor Slow During Catalyst
MonitorA slow switching oxygen sensor has been detected in
bank 2/1 during catalyst monitor test. (was P0153)
P1197 1/2 O2 Sensor Slow During Catalyst
MonitorA slow switching oxygen sensor has been detected in
bank 1/2 during catalyst monitor test. (was P0139)
P1198 Radiator Temperature Sensor Volts
Too HighRadiator coolant temperature sensor input above the
maximum acceptable voltage.
P1199 Radiator Temperature Sensor Volts
Too LowRadiator coolant temperature sensor input below the
minimum acceptable voltage.
P1281 Engine is Cold Too Long Engine coolant temperature remains below normal
operating temperatures during vehicle travel
(Thermostat).
P1282 Fuel Pump Relay Control Circuit An open or shorted condition detected in the fuel pump
relay control circuit.
P1288 Intake Manifold Short Runner
Solenoid CircuitAn open or shorted condition detected in the short
runner tuning valve circuit.
P1289 Manifold Tune Valve Solenoid
CircuitAn open or shorted condition detected in the manifold
tuning valve solenoid control circuit.
P1290 CNG Fuel System Pressure Too
HighCompressed natural gas system pressure above normal
operating range.
P1291 No Temp Rise Seen From Intake
HeatersEnergizing Heated Air Intake does not change intake air
temperature sensor an acceptable amount.
PLEMISSION CONTROL SYSTEMS 25 - 11
DESCRIPTION AND OPERATION (Continued)

MONITORED SYSTEMS
DESCRIPTION
There are new electronic circuit monitors that
check fuel, emission, engine and ignition perfor-
mance. These monitors use information from various
sensor circuits to indicate the overall operation of the
fuel, engine, ignition and emission systems and thus
the emissions performance of the vehicle.
The fuel, engine, ignition and emission systems
monitors do not indicate a specific component prob-
lem. They do indicate that there is an implied prob-
lem within one of the systems and that a specific
problem must be diagnosed.
If any of these monitors detect a problem affecting
vehicle emissions, the Malfunction Indicator (Check
Engine) Lamp will be illuminated. These monitors
generate Diagnostic Trouble Codes that can be dis-
played with the check engine lamp or a scan tool.
The following is a list of the monitored systems:
²EGR Monitor
²Misfire Monitor
²Fuel System Monitor
²Evaporative Emissions Monitor
Following is a description of each system monitor,
and its DTC.
Refer to the appropriate Powertrain Diagnos-
tics Procedures manual for diagnostic proce-
dures.
EGR MONITOR
The Powertrain Control Module (PCM) performs
an on-board diagnostic check of the EGR system.
The EGR system consists of two main components:
a vacuum solenoid back pressure transducer and a
vacuum operated valve. The EGR monitor is used to
test whether the EGR system is operating within
specifications. The diagnostic check activates only
during selected engine/driving conditions. When the
conditions are met, the EGR is turned off (solenoid
energized) and the O2S compensation control is mon-
itored. Turning off the EGR shifts the air fuel (A/F)
ratio in the lean direction. Oxygen sensor voltage
then indicates increased oxygen in the exhaust. Con-
sequently, Short Term Compensation shifts to rich
(increased injector pulse width). By monitoring the
shift, the PCM can indirectly monitor the EGR sys-
tem. While this test does not directly measure the
operation of the EGR system, it can be inferred from
the shift in the O2S data whether the EGR system is
operating correctly. Because the O2S is being used,
the O2S test must pass its test before the EGR test.
Enabling ConditionsÐ
²Engine Temperature
²Engine Run Time
²Engine RPM²MAP Sensor
²TPS
²Vehicle Speed
²Short Term Compensation
Pending ConditionsÐThe EGR Monitor does
not run when any of the following example faults
have illuminated the MIL:
²Misfire
²Oxygen Sensor Monitor
²Oxygen Sensor Heater Monitor
²Fuel System Rich/Lean
²Limp in for MAP, TPS or ECT
²Vehicle Speed Sensor
²Cam or Crank Sensor
²EGR Electrical
²EVAP Electrical
²Fuel Injector
²Ignition Coil
²Idle Speed
²Engine Coolant Temperature (ECT)
²MAP Sensor
²Intake Air Temperature (IAT)
Conflict ConditionsÐThe EGR Monitor typi-
cally does not run if any of the following conditions
are present:
²Fuel System Monitor
²Purge Monitor
²Catalyst Monitor
²Low Fuel Level
²High Altitude
²Low Ambient Air Temperature
The EGR Monitor does not run if any of the follow-
ing example DTCs are present:
²Misfire Monitor, Priority 2
²Upstream Oxygen Sensor Heater, Priority 1
²Fuel System Monitor, Priority 2
²Oxygen Sensor Monitor, Priority 1
MISFIRE MONITOR
Excessive engine misfire results in increased cata-
lyst temperature and causes an increase in HC emis-
sions. Severe misfires could cause catalyst damage.
To prevent catalytic convertor damage, the PCM
monitors engine misfire.
The Powertrain Control Module (PCM) monitors
for misfire during most engine operating conditions
(positive torque) by looking at changes in the crank-
shaft speed. If a misfire occurs the speed of the
crankshaft will vary more than normal.
OBD II regulations for misfire monitoring require
two different tests for misfire. The first is a Catalyst
Damage level of misfire test. The second is for emis-
sions greater than 1.5 times the Federal Tailpipe
(FTP) standards. The tests are monitored by two dif-
ferent counters. These counters are:
PLEMISSION CONTROL SYSTEMS 25 - 15
DESCRIPTION AND OPERATION (Continued)

²200 revolution increments for immediate cata-
lyst damage
²1000 revolution increments for emissions viola-
tion and Inspection/Maintenance (I/M) test failure
NOTE: The percent of misfire for malfunction crite-
ria varies due to RPM and load. As the engine
speed increases or load decreases, the effects of a
misfire diminishes due to crankshaft momentum.
Failure percentages also vary from engine to
engine.
Monitor OperationÐThe PCM utilizes the
Crankshaft Speed Fluctuation method to monitor for
misfire. The misfire monitor utilizes a crankshaft
position sensor to determine engine RPM. The sensor
can detect slight variations in engine speed due to
misfire. Misfire is continuously monitored once the
enabling conditions are met.
Once enabling conditions are met, the PCM counts
the number of misfires in every 200 revolutions of
the crankshaft. If, duringfive200 counters, the mis-
fire percentage exceeds a predetermined value, a
maturing code is set and a Freeze Frame is entered.
Freeze Frame data is recorded during the last 200
revolutions of the 1000 revolution period. A failure on
the second consecutive trip matures the code and a
DTC is set.
If misfire continues during the initial trip, the MIL
is not illuminated. However, the MIL flashes when
the misfire percentage exceeds the malfunction per-
centage, in any 200 revolution period, that would
cause permanent catalyst damage. This is a one trip
monitor. If misfire reaches a point in which catalyst
damage is likely to occur, the MIL flashes and a DTC
is stored in a Freeze Frame. The engine defaults to
open loop operation to prevent increased fuel flow to
the cylinders. Once misfire is below the predeter-
mined percentage, the MIL stops flashing but
remains illuminated.
The 1000 revolution counters are two trip moni-
tors. As with the fuel system monitor, Freeze Frame
data is from the original fault, and MIL extinguish-
ing requires the monitor to pass under similar condi-
tions.
The Adaptive NumeratorÐThe Misfire Monitor
takes into account component wear, sensor fatigue
and machining tolerances. The PCM compares the
crankshaft in the vehicle to data on an ideal crank
and uses this as a basis to determine variance. To do
this, the crankshaft sensor monitors the reference
notches in the crank. The PCM uses the first signal
set as a point of reference. It then measures where
the second set of signals is, compared to where engi-
neering data has determined it should be. This vari-
ance is the Adaptive Numerator. The monitor will not
run if the numerator is not set.If the Adaptive Numerator is equal to the default
value, the adaptive Numerator has not been learned
and the Misfire Monitor does not run. If the Adaptive
Numerator exceeds its limits, the PCM sets a DTC
for Adaptive Numerator and illuminates the MIL.
RPM ErrorÐThe PCM also checks the machining
tolerances for each group of slots. By monitoring the
speed of the crank from the first slot to the last slot
in a group, the PCM can calculate engine RPM. The
variance between groups of slots is know as the RPM
error. In order for the PCM to run the Misfire Mon-
itor, RPM error must be less than approximately 5%.
Enabling ConditionsÐThe following conditions
must be met before the PCM runs the Misfire Moni-
tor:
²RPM
²Engine Coolant Temperature (ECT)
²Barometric Pressure (MAP)
²Fuel level
²Ambient air Temperature
Pending ConditionsÐThe Misfire Monitor does
not run when the MIL is illuminated for any of the
following:
²Limp in mode for
Ð MAP
Ð TPS
Ð Crankshaft Sensor
Ð Engine Coolant Temperature Sensor
²Speed Sensor DTC
²EGR Electrical
²EVAP Electrical
²Idle Speed Faults
²Intake Air Temperature
²Oxygen Sensor Monitor
²Oxygen Sensor Electrical
Conflict ConditionsÐIf any of the following con-
ditions conflict with the Misfire Monitor, the monitor
will not run:
²Low fuel level
²MAP voltage rapidly changing
²Severe engine decel
²TPS toggling OPEN/CLOSED
²Engine RPM too low (RPM levels by vehicle)
²Engine RPM too high (RPM levels vary by vehi-
cle)
²Full Lean or Decel Fuel Shut-off
²Cold start
FUEL SYSTEM MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide. The catalyst works best
when the air fuel (A/F) ratio is at or near the opti-
mum of 14.7 to 1.
25 - 16 EMISSION CONTROL SYSTEMSPL
DESCRIPTION AND OPERATION (Continued)

The PCM is programmed to maintain the optimum
air/fuel ratio of 14.7 to 1. This is done by making
short term corrections in the fuel injector pulse width
based on the O2S output. The programmed memory
acts as a self calibration tool that the engine control-
ler uses to compensate for variations in engine spec-
ifications, sensor tolerances and engine fatigue over
the life span of the engine. By monitoring the actual
air-fuel ratio with the O2S (short term) and multiply-
ing that with the program long-term (adaptive) mem-
ory and comparing that to the limit, it can be
determined whether it will pass an emissions test. If
a malfunction occurs such that the PCM cannot
maintain the optimum A/F ratio, then the MIL will
be illuminated.
Monitor OperationÐFuel systems monitors do
not have a pre-test because they are continuously
running monitors. Therefore, the PCM constantly
monitors Short Term Compensation and Long Term
Adaptive memory.
Lean: If at anytime during a lean engine operation,
short term compensation multiplied by long term
adaptive exceeds a certain percentage for an
extended period, the PCM sets a Fuel System Lean
Fault for that trip and a Freeze Frame is entered.
Rich: If at anytime during a rich operation, Short
Term Compensation multiplied by Long Term Adap-
tive is less than a predetermined value, the PCM
checks the Purge Free Cells.
Purge Free Cells are values placed in Adaptive
Memory cells when the EVAP Purge Solenoid is OFF.
Two, three or four Purge Free cells are used. One cor-
responds to an Adaptive Memory cell at idle, the
other to a cell that is off-idle. For example, if a Purge
Free cell is labeled PFC1, it would hold the value for
Adaptive Memory cell C1 under non-purge condi-
tions.
If all Purge Free Cells are less than a certain per-
centage, and the Adaptive Memory factor is less than
a certain percentage, the PCM sets a Fuel System
Rich fault for that trip and a Freeze Frame is
entered.
The Fuel Monitor is a two trip monitor. The PCM
records engine data in Freeze Frame upon setting of
the first fault, or maturing code. When the fuel mon-
itor fails on a second consecutive trip, the code is
matured and the MIL is illuminated. The stored
Freeze Frame data is still from the first fault.
In order for the PCM to extinguish the MIL, the
Fuel Monitor must pass in a Similar Condition Win-
dow. The similar conditions relate to RPM and load.
The engine must be within a predetermined percent-
age of both RPM and load when the monitor runs to
count a good trip. As with all DTCs, three good tripsare required to extinguish the MIL and 40 warm up
cycles are required to erase the DTC. If the engine
does not run in a Similar Conditions Window, the
Task Manager extinguishes the MIL after 80 good
trips.
Enabling ConditionsÐThe following conditions
must be met to operate the fuel control monitor:
²PCM not in fuel crank mode (engine running)
²PCM in Closed Loop fuel control
²Fuel system updating Long Term Adaptive
²Fuel level above 15% of capacity
²Fuel level below 85% of capacity
Pending ConditionsÐThe Fuel Control Monitor
does not operate if the MIL is illuminated for any of
the following:
²Misfire Monitor
²Upstream O2S
²EVAP Purge Solenoid Electrical PCM Self Test
Fault
²Camshaft or Crankshaft Position Sensor
²Fuel Injectors
²Ignition Coil Primary
²Throttle Position (TPS) Sensor
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure (MAP) Sensor
²Idle Air Control (IAC)
²5V Output Too Low
²EGR Monitor
²EGR Solenoid Circuit
²Vehicle Speed Sensor
²Oxygen Sensor Monitor
²Oxygen Sensor Heater Monitor
²Oxygen Sensor Electrical
²Idle Speed Rationality
²Intake Air Temperature
SuspendÐThe Task Manager will suspend
maturing a Fuel System fault if any of the following
are present:
²Oxygen Sensor Response, Priority 1
²O2 Heater, Priority 1
²Misfire Monitor, Priority 2
EVAPORATIVE EMISSIONS MONITOR
LEAK DETECTION PUMP MONITORÐThe
leak detection assembly incorporates two primary
functions: it must detect a leak in the evaporative
system and seal the evaporative system so the leak
detection test can be run.
The primary components within the assembly are:
A three port solenoid that activates both of the func-
tions listed above; a pump which contains a switch,
two check valves and a spring/diaphragm, a canister
vent valve (CVV) seal which contains a spring loaded
vent seal valve.
PLEMISSION CONTROL SYSTEMS 25 - 17
DESCRIPTION AND OPERATION (Continued)

when the MIL is illuminated due to any of the fol-
lowing faults:
²Misfire
²Oxygen Sensor Monitor
²Fuel System Rich
²Fuel System Lean
²EGR Monitor
²MAP
²TPS
²ECT
²DCP Solenoid
Conflict Conditions-With or Without LDPÐ
The EVAP Monitor does not run if any of the follow-
ing tests are in progress:
²Catalyst
²EGR
²Fuel System
²Misfire
TRIP DEFINITION
OPERATION
A ªTripº means vehicle operation (following an
engine-off period) of duration and driving mode such
that all components and systems are monitored at
least once by the diagnostic system. The monitors
must successfully pass before the PCM can verify
that a previously malfunctioning component is meet-
ing the normal operating conditions of that compo-
nent. For misfire or fuel system malfunction, the
MIL may be extinguished if the fault does not recur
when monitored during three subsequent sequential
driving cycles in which conditions are similar to
those under which the malfunction was first deter-
mined.
Anytime the MIL is illuminated, a DTC is stored.
The DTC can self erase only when the MIL has been
extinguished. Once the MIL is extinguished, the
PCM must pass the diagnostic test for the most
recent DTC for 40 warm-up cycles (80 warm-up
cycles for the Fuel System Monitor and the Misfire
Monitor). A warm-up cycle can best be described by
the following:
²The engine must be running
²A rise of 40ÉF in engine temperature must occur
from the time when the engine was started
²Engine coolant temperature must reach at least
160ÉF
²A ªdriving cycleº that consists of engine start up
and engine shut off.
Once the above conditions occur, the PCM is con-
sidered to have passed a warm-up cycle. Due to the
conditions required to extinguish the MIL and erase
the DTC, it is most important that after a repair has
been made, all DTC's be erased and the repair veri-
fied.
MONITORED COMPONENT
DESCRIPTION
There are several components that will affect vehi-
cle emissions if they malfunction. If one of these com-
ponents malfunctions the Malfunction Indicator
Lamp (Check Engine) will illuminate.
Some of the component monitors are checking for
proper operation of the part. Electrically operated
components now have input (rationality) and output
(functionality) checks. Previously, a component like
the Throttle Position sensor (TPS) was checked by
the PCM for an open or shorted circuit. If one of
these conditions occurred, a DTC was set. Now there
is a check to ensure that the component is working.
This is done by watching for a TPS indication of a
greater or lesser throttle opening than MAP and
engine rpm indicate. In the case of the TPS, if engine
vacuum is high and engine rpm is 1600 or greater
and the TPS indicates a large throttle opening, a
DTC will be set. The same applies to low vacuum
and 1600 rpm.
Any component that has an associated limp in will
set a fault after 1 trip with the malfunction present.
Refer to the Diagnostic Trouble Codes Description
Charts in this section and the appropriate Power-
train Diagnostic Procedure Manual for diagnostic
procedures.
The following is a list of the monitored compo-
nents:
²Comprehensive Components
²Oxygen Sensor Monitor
²Oxygen Sensor Heater Monitor
²Catalyst Monitor
COMPREHENSIVE COMPONENTS
Along with the major monitors, OBD II requires
that the diagnostic system monitor any component
that could affect emissions levels. In many cases,
these components were being tested under OBD I.
The OBD I requirements focused mainly on testing
emissions-related components for electrical opens and
shorts.
However, OBD II also requires that inputs from
powertrain components to the PCM be tested for
rationality, and that outputs to powertrain compo-
nents from the PCM be tested forfunctionality.
Methods for monitoring the various Comprehensive
Component monitoring include:
(1) Circuit Continuity
²Open
²Shorted high
²Shorted to ground
(2) Rationality or Proper Functioning
²Inputs tested for rationality
²Outputs tested for functionality
PLEMISSION CONTROL SYSTEMS 25 - 19
DESCRIPTION AND OPERATION (Continued)