display DODGE NEON 2000 Service User Guide

(3) After the ignition switch has been in the ON
position for about three seconds, but no more than
fifteen seconds, cycle the ignition switch back to the
OFF position. Replace the first valid Sentry Key in
the ignition lock cylinder with the second valid Sen-
try Key and turn the ignition switch back to the ON
position. Both operations must be performed within
15 seconds.
(4) About ten seconds after the completion of Step
3, the VTSS indicator LED will start to flash and a
single audible chime tone will sound to indicate that
the system has entered the ªCustomer Learnº pro-
gramming mode.
(5) Within about fifty seconds of entering the ªCus-
tomer Learnº programming mode, turn the ignition
switch to the OFF position, replace the valid Sentry
Key with a blank Sentry Key transponder, and turn
the ignition switch back to the ON position.
(6) About ten seconds after the completion of Step
5, a single audible chime tone will sound and the
VTSS indicator LED will stop flashing and stay on
solid for about three seconds to indicate that the
blank Sentry Key transponder has been successfully
programmed. The SKIS will immediately return to
normal system operation following exit from the
ªCustomer Learnº programming mode.
(7) Go back to Step 2 and repeat this process for
each additional Sentry Key transponder blank to be
programmed.
If any of the above steps is not completed in the
proper sequence, or within the allotted time, the
SKIS will automatically exit the ªCustomer Learnº
programming mode. The SKIS will also automatically
exit the ªCustomer Learnº programming mode if it
sees a non-blank Sentry Key transponder when it
should see a blank, if it has already programmed
eight valid Sentry Keys, or if the ignition switch is
turned to the OFF position for more than about fifty
seconds.
PROGRAMMING BLANK SENTRY KEY
TRANSPONDERS WITH A DRB lllTSCAN TOOL
When programming a blank Sentry Key transpon-
der, the key blank must first be cut to match the
ignition lock cylinder. It will also be necessary to
enter the vehicle's four digit PIN code into the DRB
IIItscan tool to enter the Sentry Key Immobilizer
Module's (SKIM's) secured access mode.
NOTE: Once a Sentry Key is programmed to a par-
ticular vehicle, it cannot be transferred to another
vehicle.
Insert the blank key into the ignition and turn it to
the RUN position. Using the DRB IIItscan tool,
select ªTheft Alarm,º then ªSKIM,º then ªMiscella-
neous.º Select ªProgram New Key.º Enter the fourdigit PIN code using the DRB IIIt. When program-
ming is completed, the SKIM will exit secured access
mode and display the status of the key. One of five
different status messages may be displayed as fol-
lows:
²ªProgramming Successfulº is displayed if SKIM
Sentry Key programming succeeds.
²ªLearned Key in Ignitionº is displayed if the key
in the ignition has already been programmed into
that vehicle's SKIM.
²ª8 Keys Already Learned (At The Maximum)
Programming Not Doneº is displayed if eight keys
have already been programmed into the SKIM. In
this case, if a new key needs to be added due to a
lost or defective key, the ªErase All Keysº function
(requires entering secured access mode) has to be
performed. Then the customer is seven keys plus the
new key MUST be reprogrammed into the SKIM.
²ªProgramming Not Attemptedº is displayed after
an ªErase All Keysº function is executed.
²ªProgramming Key Failedº is displayed if fur-
ther diagnosis is required.
²To learn additional keys, turn the ignition OFF,
remove the learned key, and insert the next new
blank key. Turn ignition to the RUN position and re-
enter the secured access mode function and repeat
the ªProgram New Keyº procedure outlined above.
SWITCHING OPERATING MODES/
CONFIGURING A NEW MODULE
To switch operating modes or to configure a new
module, a DRB IIItscan tool must be used.
(1) Hook up the DRB IIItscan tool to the Data
Link Connector (DLC) (Fig. 4).
(2) With the key in the ignition, turn the key to
the RUN position.
(3) After the DRB IIItscan tool initialization, per-
form the following:
(a) Select ªTheft Alarm.º
(b) Select ªVTSS.º
(c) Select ªMiscellaneous.º
(4) Once in the ªMiscellaneousº screen:
(a) If you wish to configure a new module, select
ªConfigure Module.º
(b) If you wish to put the module into customer
usage mode, select ªEnable VTSS.º
(c) If you wish to put the module into dealer lot
mode, select ªDealer Lot.º
8Q - 6 VEHICLE THEFT/SECURITY SYSTEMPL
SERVICE PROCEDURES (Continued)

15
MODULE ENTRY
KEYLESS
REMOTE
20
13 26
X161
20
WT
15A
FUSE
13
POWER
DISTRIBUTION
CENTER BATT A0
4
2 14
SIREN
3
G103 S117
C104C19
19
C305
C3014 11 A11 M1
20
PK
M1
20
PK
X5
22
WT/RD
X5
20
WT/RD
X5
20
WT/RDX5
20
WT/RD
G120
18
WT/DBG120
18
WT/BK
G120
18
WT/DB
G120
18
WT/DB
Z1
18
BK
LHD RHD
SENSOR INTRUSION
LAMP/
DOME
DISPLAY
BACKLIGHT DISPLAY
BACKLIGHT FUSED
B(+)
GROUNDJAPAN JAPAN
S120 S103
ANTENNA ANTENNA
INTRUSION
SENSOR
SIGNAL DISPLAY
BACKLIGHT SIGNALSENSOR INTRUSION
RHD
Z1
12
BK
13(8W-10-12)(8W-10-2)
(8W-10-3) (8W-10-7)
(8W-15-7) (8W-15-7)(8W-44-2) (8W-10-12)
8W - 39 - 14 8W-39 VEHICLE THEFT SECURITY SYSTEM
BUILT-UP-EXPORTPL
008W-10PLI03914

LHD
RHD
Z2 22BK/LGGROUND
F9 20RD/BKFUSED B(+)
PASSENGER DOOR SWITCH MUX
P96 20LG/BK
- -
L7 20BK/YLDIMMER SWITCH LOW BEAM OUTPUT
REMOTE KEYLESS
ENTRY MODULE
1411
12
13
9 5
6
8 7 3
4 2 1CIRCUIT CAV
10
21 15
18
19 17 16
20
24 23 22
25
26
F35 18RDHEADLAMP SWITCH OUTPUT
P33 18OR/BKFUSED B(+)
P34 18PK/BKDOOR LOCK DRIVER
P36 18PK/VTDOOR UNLOCK DRIVER
M9 20DB/ORDOOR UNLOCK DRIVER
PASSENGER DOOR AJAR/ RKE SENSE
P97 20LGDRIVER DOOR SWITCH MUX
Z1 20BKGROUND
X161 20WTRKE ANTENNA
X5 22WT/RDDISPLAY BACKLIGHT
Q2 16LG/BKDECKLID RELEASE RELAY OUTPUT
G69 20BK/ORVTSS INDICATOR DRIVER
X3 22BK/RDHORN RELAY CONTROL
D25 20VT/YLPCI BUS
G120 18WT/BKINTRUSION SENSOR SIGNAL
M1 20PKFUSED B(+)
G5 20DB/WTFUSED IGNITION SWITCH OUTPUT (ST-RUN)
G70 20BR/TNHOOD AJAR SWITCH SENSE
G71 20VT/YLDECKLID SECURITY SWITCH SENSE
G75 18TNDRIVER DOOR AJAR SWITCH SENSE
X161 20WTJAPAN ANTENNA L4 16VT/WT
BUILT-UP-EXPORT
1
13
14
26REAR WINDOW DEFOGGER RELAY OUTPUT
C15 12BKPANEL LAMPS DRIVER
E2 20OR Z2 22BK/LGGROUND F20 20WTFUSED IGNITION SWITCH OUTPUT (RUN) A4 12BK/RDFUSED B(+)
SWITCH
51
DEFOGGER REAR WINDOW
FUNCTION
CAV CIRCUIT
1
2
4 3
5
F35 18RD/YL
FUSED B(+) 3
5
C15 12BK/WTRAER WINDOW DEFOGGER RELAY OUTPUT
INTRUSION SENSOR SIGNAL
G120 18WT/DB20
BLACK
BLACK
FUNCTION
8W - 80 - 40 8W-80 CONNECTOR PIN-OUTSPL
J008W-10PLI08040

CAV CIRCUIT FUNCTION
1
Z1 18BK GROUND
2
L7 18BK/YL HEADLAMP SWITCH OUTPUT
3 L62 18BR/RD RIGHT TURN SIGNAL
RIGHT TAIL/STOP/
TURN SIGNAL LAMP
SEAT BELT SWITCH
1 2
BLACK
SEAT BELT SWITCH SENSE 20LG/RD G10 1
GROUND 18BK Z1 2
FUNCTION CIRCUIT CAV
(EXCEPT BUILT-UP-EXPORT)
M1 20PKFUSED B(+) GROUND
Z1 18BK X5 20WT/RDDISPLAY BACKLIGHT
4
1
SIREN
DISPLAY BACKLIGHT
X5 20WT/RDFUNCTION
CAV CIRCUIT
1
2
4 3
MODULE IMMOBILIZER
- -- -
FUSED B(+)
M1 20PKGROUND
Z2 20BK/LGFUSED IGNITION SWITCH OUTPUT (ST-RUN)
G5 20DB/WTPCI BUS D25 22VT/YL1
6
SENTRY KEY
FUNCTION
CAV CIRCUIT
1
2
4 3
6 5
RIGHT TAIL/STOP
LAMP
(BUILT-UP-EXPORT)
1 3
HEADLAMP SWITCH OUTPUTGROUND Z1 18BK
3
CAV CIRCUIT FUNCTION
1
L50 18WT/TN BRAKE LAMP SWITCH OUTPUT 2 L7 18BK/YL
(BUILT-UP-EXPORT)
31
BLACK
BLACK
BLACK
PL8W-80 CONNECTOR PIN-OUTS 8W - 80 - 45
PLI08045008W-10

As the engine enters one of these cells the PCM
looks at the amount of short term correction being
used. Because the goal is to keep short term at 0 (O2
Sensor switching at 0.5 volt), long term will update
in the same direction as short term correction was
moving to bring the short term back to 0. Once short
term is back at 0, this long term correction factor is
stored in memory.
The values stored in long term adaptive memory
are used for all operating conditions, including open
loop. However, the updating of the long term memoryoccurs after the engine has exceeded approximately
17É F, with fuel control in closed loop and two min-
utes of engine run time. This is done to prevent any
transitional temperature or start-up compensations
from corrupting long term fuel correction.
Long term adaptive memory can change the pulse-
width by as much as 25%, which means it can correct
for all of short term. It is possible to have a problem
that would drive long term to 25% and short term to
another 25% for a total change of 50% away from
base pulse-width calculation.
TYPICAL ADAPTIVE MEMORY FUEL CELLS
Open
ThrottleOpen
ThrottleOpen
ThrottleOpen
ThrottleOpen
ThrottleOpen
Throttle Idle Decel
Vacuum 20 17 13 9 5 0
Above 1,984
rpm1 3 5 7 9 11 13 Drive 15
Below 1,984
rpm02 4 6 8 1012
Neutral14
MAP volt =0 1.4 2.0 2.6 3.3 3.9
Fuel Correction Diagnostics
There are two fuel correction diagnostic routines:
²Fuel System Rich
²Fuel System Lean
A DTC is set and the MIL is illuminated if the
PCM detects either of these conditions.
PROGRAMMABLE COMMUNICATIONS
INTERFACE (PCI) BUS
OPERATION
Various modules exchange information through a
communications port called the PCI Bus. The Power-
train Control Module (PCM) transmits the Malfunc-
tion Indicator Lamp (Check Engine) On/Off signal
and engine RPM on the PCI Bus. The PCM receives
the Air Conditioning select input, transaxle gear
position inputs over the PCI Bus. The PCM also
receives the air conditioning evaporator temperature
signal from the PCI Bus.
The following components access or send informa-
tion on the PCI Bus.
²Instrument Panel
²Body Control Module
²Air Bag System Diagnostic Module
²Full ATC Display Head
²ABS Module
²Transmission Control Module
²Powertrain Control Module
²Overhead Travel Module
AIR CONDITIONING PRESSURE
TRANSDUCERÐPCM INPUT
OPERATION
The Powertrain Control Module (PCM) monitors
the A/C compressor discharge (high side) pressure
through the air conditioning pressure transducer.
The transducer supplies an input to the PCM. The
PCM engages the A/C compressor clutch if pressure
is sufficient for A/C system operation.
AUTOMATIC SHUTDOWN (ASD) SENSEÐPCM
INPUT
OPERATION
The ASD sense circuit informs the PCM when the
ASD relay energizes. A 12 volt signal at this input
indicates to the PCM that the ASD has been acti-
vated. This input is used only to sense that the ASD
relay is energized.
When energized, the ASD relay supplies battery
voltage to the fuel injectors, ignition coils and the
heating element in each oxygen sensor. If the PCM
does not receive 12 volts from this input after
grounding the ASD relay, it sets a Diagnostic Trouble
Code (DTC).
PLFUEL SYSTEM 14 - 27
DESCRIPTION AND OPERATION (Continued)

signal to the PCM, allowing engine starter operation.
The interlock switch is not adjustable.
Clutch Pedal Upstop Switch
With the clutch pedal at rest, the clutch pedal
upstop switch is closed, allowing speed control oper-
ation. When the clutch pedal is depressed, the upstop
switch opens and signals the PCM to cancel speed
control operation, and enter a modified engine cali-
bration schedule to improve driveability during gear-
to-gear shifts. The upstop switch is not adjustable.
CRANKSHAFT POSITION SENSORÐPCM
INPUT
DESCRIPTION
The crankshaft position sensor mounts to the front
of the engine block (Fig. 8).
OPERATION
The PCM determines what cylinder to fire from the
crankshaft position sensor input and the camshaft
position sensor input. The second crankshaft counter-
weight has two sets of four timing reference notches
including a 60 degree signature notch (Fig. 9). From
the crankshaft position sensor input the PCM deter-
mines engine speed and crankshaft angle (position).
The notches generate pulses from high to low in
the crankshaft position sensor output voltage. When
a metal portion of the counterweight aligns with the
crankshaft position sensor, the sensor output voltage
goes low (less than 0.5 volts). When a notch aligns
with the sensor, voltage goes high (5.0 volts). As a
group of notches pass under the sensor, the output
voltage switches from low (metal) to high (notch)
then back to low.If available, an oscilloscope can display the square
wave patterns of each voltage pulses. From the width
of the output voltage pulses, the PCM calculates
engine speed. The width of the pulses represent the
amount of time the output voltage stays high before
switching back to low. The period of time the sensor
output voltage stays high before switching back to
low is referred to as pulse width. The faster the
engine is operating, the smaller the pulse width on
the oscilloscope.
By counting the pulses and referencing the pulse
from the 60 degree signature notch, the PCM calcu-
lates crankshaft angle (position). In each group of
timing reference notches, the first notch represents
69 degrees before top dead center (BTDC). The sec-
ond notch represents 49 degrees BTDC. The third
notch represents 29 degrees. The last notch in each
set represents 9 degrees before top dead center
(TDC).
The timing reference notches are machined at 20É
increments. From the voltage pulse width the PCM
tells the difference between the timing reference
notches and the 60 degree signature notch. The 60
degree signature notch produces a longer pulse width
than the smaller timing reference notches. If the
camshaft position sensor input switches from high to
low when the 60 degree signature notch passes under
the crankshaft position sensor, the PCM knows cylin-
der number one is the next cylinder at TDC.
The PCM uses the Crankshaft Position sensor to
calculate the following: Engine RPM, TDC number 1
and 4, Ignition coil synchronization, Injection Syn-
chronization, Camshaft-to-crankshaft misalignment
where applicable (Timing belt skipped 1 tooth or
more diagnostic trouble code).
The PCM sends approximately 9 volts to the Hall-
effect 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.
ENGINE COOLANT TEMPERATURE SENSORÐ
PCM INPUT
DESCRIPTION
The coolant sensor threads into the rear of the cyl-
inder head, next to the camshaft position sensor (Fig.
10). New sensors have sealant applied to the threads.
The ECT Sensor is a Negative Thermal Coefficient
(NTC), dual range Sensor. The resistance of the ECT
Sensor changes as coolant temperature changes. This
results in different input voltages to the PCM. The
PCM also uses the ECT Sensor input to operate the
low and high speed radiator cooling fans.
Fig. 8 Crankshaft Position Sensor
14 - 30 FUEL SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

EMISSION CONTROL SYSTEMS
TABLE OF CONTENTS
page page
ON-BOARD DIAGNOSTICS................... 1 EVAPORATIVE EMISSION CONTROLS......... 25
ON-BOARD DIAGNOSTICS
TABLE OF CONTENTS
page page
DESCRIPTION AND OPERATION
SYSTEM DESCRIPTION....................1
TASK MANAGER..........................2
MALFUNCTION INDICATOR LAMP (MIL)........5
DRB III STATE DISPLAY TEST MODE..........5
DRB III CIRCUIT ACTUATION TEST MODE......5
DIAGNOSTIC TROUBLE CODES..............5
DIAGNOSTIC TROUBLE CODE
DESCRIPTIONS.........................6MONITORED SYSTEMS....................15
TRIP DEFINITION........................19
MONITORED COMPONENT.................19
NON-MONITORED CIRCUITS...............23
HIGH AND LOW LIMITS....................24
LOAD VALUE............................24
DESCRIPTION AND OPERATION
SYSTEM DESCRIPTION
DESCRIPTION
OBD II requires that vehicles falling under OBD II
guidelines utilize the following system monitors:
²Comprehensive Component Monitor (inputs/out-
puts for powertrain management that affect emis-
sions, but do not have a specific major monitor)
²Fuel Control Monitor (fuel compensation
required to maintain stoichiometric ratio rich/lean)
²Misfire Monitor (change in crankshaft speed)
²Oxygen Sensor Heater Monitor (response and
performance of oxygen sensors)
²Catalyst Monitor (Performance and efficiency of
catalyst)
²Evaporative Emissions Monitor (performance of
and leaks from EVAP system)
²Exhaust Gas Recirculation Monitor (flow perfor-
mance of EGR system)
The software was rewritten to enable the PCM to
carry out the responsibilities to meet these required
guidelines. The PCM now contains a Task Manager.
OPERATION
The Powertrain Control Module (PCM) monitors
many different circuits in the fuel injection, ignition,
emission and engine systems. If the PCM senses a
problem with a monitored circuit often enough to
indicate an actual problem, it stores a Diagnostic
Trouble Code (DTC) in the PCM's memory. If the
code applies to a non-emissions related component or
system, and the problem is repaired or ceases to
exist, the PCM cancels the code after 40 warmup
cycles. Diagnostic trouble codes that affect vehicle
emissions illuminate the Malfunction Indicator Lamp
(MIL). Refer to Malfunction Indicator Lamp in this
section.
Certain criteria must be met before the PCM
stores a DTC in memory. The criteria may be a spe-
cific range of engine RPM, engine temperature,
and/or input voltage to the PCM.
The PCM might not store a DTC for a monitored
circuit even though a malfunction has occurred. This
may happen because one of the DTC criteria for the
circuit has not been met.For example, assume the
diagnostic trouble code criteria requires the PCM to
monitor the circuit only when the engine operates
between 750 and 2000 RPM. Suppose the sensor's
output circuit shorts to ground when engine operates
above 2400 RPM (resulting in 0 volt input to the
PLEMISSION CONTROL SYSTEMS 25 - 1

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)

that may induce an erroneous failure. This prevents
illuminating the MIL for the wrong fault and allows
more precis diagnosis.
For example, if the PCM is storing a one trip fault
for the Oxygen Sensor and the EGR monitor, the
Task Manager may still run the EGR Monitor but
will suspend the results until the Oxygen Sensor
Monitor either passes or fails. At that point the Task
Manager can determine if the EGR system is actu-
ally failing or if an Oxygen Sensor is failing.
MIL Illumination
The PCM Task Manager carries out the illumina-
tion of the MIL. The Task Manager triggers MIL illu-
mination upon test failure, depending on monitor
failure criteria.
The Task Manager Screen shows both a Requested
MIL state and an Actual MIL state. When the MIL is
illuminated upon completion of a test for a third trip,
the Requested MIL state changes to OFF. However,
the MIL remains illuminated until the next key
cycle. (On some vehicles, the MIL will actually turn
OFF during the third key cycle) During the key cycle
for the third good trip, the Requested MIL state is
OFF, while the Actual MILL state is ON. After the
next key cycle, the MIL is not illuminated and both
MIL states read OFF.
Diagnostic Trouble Codes (DTCs)
With OBD II, different DTC faults have different
priorities according to regulations. As a result, the
priorities determine MIL illumination and DTC era-
sure. DTCs are entered according to individual prior-
ity. DTCs with a higher priority overwrite lower
priority DTCs.
Priorities
²Priority 0 ÐNon-emissions related trouble codes
²Priority 1 Ð One trip failure of a two trip fault
for non-fuel system and non-misfire.
²Priority 2 Ð One trip failure of a two trip fault
for fuel system (rich/lean) or misfire.
²Priority3ÐTwotrip failure for a non-fuel sys-
tem and non-misfire or matured one trip comprehen-
sive component fault.
²Priority4ÐTwotrip failure or matured fault
for fuel system (rich/lean) and misfire or one trip cat-
alyst damaging misfire.
Non-emissions related failures have no priority.
One trip failures of two trip faults have low priority.
Two trip failures or matured faults have higher pri-
ority. One and two trip failures of fuel system and
misfire monitor take precedence over non-fuel system
and non-misfire failures.DTC Self Erasure
With one trip components or systems, the MIL is
illuminated upon test failure and DTCs are stored.
Two trip monitors are components requiring failure
in two consecutive trips for MIL illumination. Upon
failure of the first test, the Task Manager enters a
maturing code. If the component fails the test for a
second time the code matures and a DTC is set.
After three good trips the MIL is extinguished and
the Task Manager automatically switches the trip
counter to a warm-up cycle counter. DTCs are auto-
matically erased following 40 warm-up cycles if the
component does not fail again.
For misfire and fuel system monitors, the compo-
nent must pass the test under a Similar Conditions
Window in order to record a good trip. A Similar Con-
ditions Window is when engine RPM is within6375
RPM and load is within610% of when the fault
occurred.
NOTE: It is important to understand that a compo-
nent does not have to fail under a similar window of
operation to mature. It must pass the test under a
Similar Conditions Window when it failed to record
a Good Trip for DTC erasure for misfire and fuel
system monitors.
DTCs can be erased anytime with a DRB III. Eras-
ing the DTC with the DRB III erases all OBD II
information. The DRB III automatically displays a
warning that erasing the DTC will also erase all
OBD II monitor data. This includes all counter infor-
mation for warm-up cycles, trips and Freeze Frame.
Trip Indicator
TheTripis essential for running monitors and
extinguishing the MIL. In OBD II terms, a trip is a
set of vehicle operating conditions that must be met
for a specific monitor to run. All trips begin with a
key cycle.
Good Trip
The Good Trip counters are as follows:
²Global Good Trip
²Fuel System Good Trip
²Misfire Good Trip
²Alternate Good Trip (appears as a Global Good
Trip on DRB III)
²Comprehensive Components
²Major Monitor
²Warm-Up Cycles
Global Good Trip
To increment a Global Good Trip, the Oxygen sen-
sor and Catalyst efficiency monitors must have run
and passed.
Fuel System Good Trip
To count a good trip (three required) and turn off
the MIL, the following conditions must occur:
PLEMISSION CONTROL SYSTEMS 25 - 3
DESCRIPTION AND OPERATION (Continued)

²Engine in closed loop
²Operating in Similar Conditions Window
²Short Term multiplied by Long Term less than
threshold
²Less than threshold for a predetermined time
If all of the previous criteria are met, the PCM will
count a good trip (three required) and turn off the
MIL.
Misfire Good Trip
If the following conditions are met the PCM will
count one good trip (three required) in order to turn
off the MIL:
²Operating in Similar Condition Window
²1000 engine revolutions with no misfire
Alternate Good Trip
Alternate Good Trips are used in place of Global
Good Trips for Comprehensive Components and
Major Monitors. If the Task Manager cannot run a
Global Good Trip because a component fault is stop-
ping the monitor from running, it will attempt to
count an Alternate Good Trip.
The Task Manager counts an Alternate Good Trip
for Comprehensive components when the following
conditions are met:
²Two minutes of engine run time
²No other faults occur
The Task Manager counts an Alternate Good Trip
for a Major Monitor when the monitor runs and
passes. Only the Major Monitor that failed needs to
pass to count an Alternate Good Trip.
Warm-Up Cycles
Once the MIL has been extinguished by the Good
Trip Counter, the PCM automatically switches to a
Warm-Up Cycle Counter that can be viewed on the
DRB III. Warm-Up Cycles are used to erase DTCs
and Freeze Frames. Forty Warm-Up cycles must
occur in order for the PCM to self-erase a DTC and
Freeze Frame. A Warm-Up Cycle is defined as fol-
lows:
²Engine coolant temperature must start below
and rise above 160É F
²Engine coolant temperature must rise by 40É F
²No further faults occur
Freeze Frame Data Storage
Once a failure occurs, the Task Manager records
several engine operating conditions and stores it in a
Freeze Frame. The Freeze Frame is considered one
frame of information taken by an on-board data
recorder. When a fault occurs, the PCM stores the
input data from various sensors so that technicians
can determine under what vehicle operating condi-
tions the failure occurred.
The data stored in Freeze Frame is usually
recorded when a system fails the first time for twotrip faults. Freeze Frame data will only be overwrit-
ten by a different fault with a higher priority.
CAUTION: Erasing DTCs, either with the DRB III or
by disconnecting the battery, also clears all Freeze
Frame data.
Similar Conditions Window
The Similar Conditions Window displays informa-
tion about engine operation during a monitor. Abso-
lute MAP (engine load) and Engine RPM are stored
in this window when a failure occurs. There are two
different Similar conditions Windows: Fuel System
and Misfire.
FUEL SYSTEM
²Fuel System Similar Conditions WindowÐ
An indicator that 'Absolute MAP When Fuel Sys Fail'
and 'RPM When Fuel Sys Failed' are all in the same
range when the failure occurred. Indicated by switch-
ing from 'NO' to 'YES'.
²Absolute MAP When Fuel Sys FailÐ The
stored MAP reading at the time of failure. Informs
the user at what engine load the failure occurred.
²Absolute MAPÐ A live reading of engine load
to aid the user in accessing the Similar Conditions
Window.
²RPM When Fuel Sys FailÐ The stored RPM
reading at the time of failure. Informs the user at
what engine RPM the failure occurred.
²Engine RPMÐ A live reading of engine RPM
to aid the user in accessing the Similar Conditions
Window.
²Adaptive Memory FactorÐ The PCM uti-
lizes both Short Term Compensation and Long Term
Adaptive to calculate the Adaptive Memory Factor
for total fuel correction.
²Upstream O2S VoltsÐ A live reading of the
Oxygen Sensor to indicate its performance. For
example, stuck lean, stuck rich, etc.
²SCW Time in Window (Similar Conditions
Window Time in Window)Ð A timer used by the
PCM that indicates that, after all Similar Conditions
have been met, if there has been enough good engine
running time in the SCW without failure detected.
This timer is used to increment a Good Trip.
²Fuel System Good Trip CounterÐATrip
Counter used to turn OFF the MIL for Fuel System
DTCs. To increment a Fuel System Good Trip, the
engine must be in the Similar Conditions Window,
Adaptive Memory Factor must be less than cali-
brated threshold and the Adaptive Memory Factor
must stay below that threshold for a calibrated
amount of time.
²Test Done This TripÐ Indicates that the
monitor has already been run and completed during
the current trip.
25 - 4 EMISSION CONTROL SYSTEMSPL
DESCRIPTION AND OPERATION (Continued)