window switch JEEP GRAND CHEROKEE 2002 WJ / 2.G Repair Manual

However, evaporator capacity used to reduce the
amount of moisture in the air is not wasted. Wring-
ing some of the moisture out of the air entering the
vehicle adds to the comfort of the passengers.
Although, an owner may expect too much from their
air conditioning system on humid days. A perfor-
mance test is the best way to determine whether the
system is performing up to standard. This test also
provides valuable clues as to the possible cause of
trouble with the air conditioning system.
If the vehicle has the optional Automatic Zone Control
(AZC) system, and has intermittent operational prob-
lems or fault codes, be certain that the wire harness
connectors on the HVAC housing are properly seated
(Fig. 2). To check this condition, unplug the two wire
harness connector halves, then plug them in again.
Before performing the following procedure, (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING - CAUTION) (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - WARNING). The air
temperature in the test room and in the vehicle must
be a minimum of 21É C (70É F) for this test.
(1)
Connect a tachometer and a manifold gauge set.
(2) If the vehicle has the standard manual temper-
ature control, set the A/C Heater mode control switch
knob in the Panel position, the temperature control
knob in the full cool (Fresh Air Mode) position, the
A/C button in the On position, and the blower motor
switch knob in the highest speed position. If the vehi-
cle has the optional AZC, set the A/C Heater mode
control switch knob in the Panel position, the tem-
perature control knob in the full cool position, the
A/C button in the On position, and the blower motor
switch knob in the highest (manual) speed position.
(3) Start the engine and hold the idle at 1,300 rpm
with the compressor clutch engaged.
(4) The engine should be at operating temperature.
The doors and windows must be open.
(5)
Insert a thermometer in the driver side center
A/C (panel) outlet. Operate the engine for five minutes.
(6) The compressor clutch may cycle, depending
upon the ambient temperature and humidity.(7) With the compressor clutch engaged, record the
discharge air temperature and the compressor dis-
charge pressure.
(8) Compare the discharge air temperature to the
Performance Temperature and Pressure chart. If the
discharge air temperature is high, (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
DIAGNOSIS AND TESTING - REFRIGERANT SYS-
TEM LEAKS) and (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - STANDARD PRO-
CEDURE - REFRIGERANT SYSTEM CHARGE).
Performance Temperature and Pressure
Ambient Air Temperature
and Humidity21É C
(70É F @ 80%
humidity)27É C
(80É F @ 80%
humidity)32É C
(90É F @ 80%
humidity)38É C
(100ÉF@50%
humidity)43É C
110É F @ 20%
humidity)
Air Temperature at Center
Panel Outlet10 to 13É C
(50 to 55É F)14 to 17É C
(58 to 63É F)15 to 18É C
(60 to 65É F)17 to 20É C
(63 to 68É F)14 to 17É C
(58 to 63É F)
Evaporator Inlet Pressure
at Charge Port241 to 276 kPa
(35 to 40 psi)262 to 290 kPa
(38 to 42 psi)269 to 296 kPa
(39 to 43 psi)275 to 303 kPa
(40 to 44 psi)262 to 290 kPa
(38 to 42 psi)
Compressor Discharge
Pressure1241 to 1792
kPa
(180 to 260 psi)1380 to 1930
kPa
(200 to 280 psi)1380 to 1930
kPa
(200 to 280 psi)1655 to 2206
kPa
(240 to 320 psi)1567 to 2068
kPa
(220 to 300 psi)
Note: The discharge air temperatures will be lower if the humidity is less than the percentages shown.
Fig. 2 HVAC Housing - (rear view)
1 - Instrument Panel
2 - Air Intake
3 - Expansion Valve
4 - HVAC Housing
5 - Heater Core Input/Output Ports
6 - Instrument Panel Wiring Harness
7 - Blower Motor
WJHEATING & AIR CONDITIONING 24 - 3
HEATING & AIR CONDITIONING (Continued)

open circuit to the fuse in the junction block as
required.
(5) The coil ground terminal cavity (85) is switched
to ground through the Powertrain Control Module
(PCM). There should be continuity between this cav-
ity and the A/C compressor clutch relay control cir-
cuit cavity of the PCM wire harness connector C
(gray) at all times. If not OK, repair the open circuit
as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cover from the Power Distribution
Center (PDC) (Fig. 11).
(3) Refer to the label on the PDC for compressor
clutch relay identification and location.
(4) Unplug the compressor clutch relay from the
PDC.
INSTALLATION
(1) Install the compressor clutch relay by aligning
the relay terminals with the cavities in the PDC and
pushing the relay firmly into place.
(2) Install the PDC cover.
(3) Connect the battery negative cable.
(4) Test the relay operation.
A/C HEATER CONTROL
DESCRIPTION
The manual temperature control HVAC system
uses a combination of electrical, and vacuum con-trols. The Automatic Zone Control (AZC) HVAC sys-
tem uses only electrical controls. These controls
provide the vehicle operator with a number of setting
options to help control the climate and comfort
within the vehicle. Refer to the owner's manual in
the vehicle glove box for more information on the
suggested operation and use of these controls.
Both a/c heater control panels are located on the
instrument panel inboard of the steering column and
below the radio (Fig. 12). Both control panels contain
rotary-type temperature control knob(s), a rotary-
type mode control switch knob, a rotary-type blower
motor speed switch knob and an air conditioning
compressor push button switch. The rear window
defogger push button switch is also located on a/c
heater control panel. The AZC control panel also fea-
tures a recirculation push button switch and a vac-
uum fluorescent display area.
OPERATION
The AZC control module uses infrared sensing
technology to control occupant comfort levels, not the
actual passenger compartment air temperature. Dual
infrared sensors mounted in the face of the control
unit independently measure the surface temperature
to maintain customer-perceived comfort temperature
under changing conditions. Dual Zone temperature
control provides wide side-to-side variation in comfort
temperature to exceed the needs of either front seat
occupant. This sensing system replaces interior air
temperature and solar sensors used to approximate
direct sensing control through complex control pro-
grams.
Fig. 11 POWER DISTRIBUTION CENTER (PDC)
1 - TRANSMISSION CONTROL MODULE (TCM)
2 - NEGATIVE CABLE
3 - POSITIVE CABLE
4 - POWER DISTRIBUTION CENTER (PDC)
Fig. 12 A/C HEATER CONTROL PANELS
WJCONTROLS 24 - 17
A/C COMPRESSOR CLUTCH RELAY (Continued)

WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Check for battery voltage at the fuse in the
Power Distribution Center (PDC). If OK, go to Step
2. If not OK, repair the shorted circuit or component
as required and replace the faulty fuse.
(2) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the a/c heater control from the instrument
panel. (Refer to 24 - HEATING & AIR CONDITION-
ING/CONTROLS/A/C HEATER CONTROL -
REMOVAL) Check for continuity between the ground
circuit cavity of the a/c heater control wire harness
connector and a good ground. There should be conti-
nuity. If OK, go to Step 3. If not OK, repair the open
circuit to ground as required.
(3) With the a/c heater control wire harness con-
nector unplugged, place the a/c heater mode control
switch knob in any position except the Off position.
Check for continuity between the ground circuit ter-
minal and each of the blower motor driver circuit ter-
minals of the a/c heater control as you move the
blower motor switch knob to each of the four speed
positions. There should be continuity at each driver
circuit terminal in only one blower motor switch
speed position. If OK, test and repair the blower
driver circuits between the a/c heater control connec-
tor and the blower motor resistor as required. If not
OK, replace the faulty a/c heater control unit.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTALAIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
The blower motor switch cannot be adjusted or
repaired, and if faulty or damaged, the a/c heater
control must be replaced. (Refer to 24 - HEATING &
AIR CONDITIONING/CONTROLS/A/C HEATER
CONTROL - REMOVAL)
IN-CAR TEMPERATURE
SENSOR
DESCRIPTION
Models equipped with the optional Automatic Zone
Control (AZC) system use automatic dual zone tem-
perature control with infrared sensing technology.
The temperature sensor is located in the center
instrument panel, between the dual temperature
knobs of the AZC.
OPERATION
The Automatic Zone Control uses infrared sensing
technology to control occupant comfort levels, not the
actual passenger compartment air temperature. Dual
infrared sensors mounted in the face of the control
unit independently measure the surface temperature
to maintain customer-perceived comfort temperature
under changing conditions. Dual Zone temperature
control provides wide side-to-side variation in comfort
temperature to exceed the needs of either front seat
occupant. This sensing system replaces interior air
temperature and solar sensors used to approximate
direct sensing control through complex control pro-
grams.
The infrared temperature sensor cannot be
adjusted or repaired and, if faulty or damaged, the
AZC head must be replaced.
NOTE: The infrared sensor window may be perma-
nently damaged if any type of cosmetic vinyl dress-
ings are allowed to contact the lens. Avoid spraying
or wiping this area with any cleaner or conditioner.
This may result in impaired temperature sensing
and control.
REMOVAL
The infrared temperature sensor cannot be
adjusted or repaired and, if faulty or damaged, the
AZC head must be replaced. (Refer to 24 - HEATING
& AIR CONDITIONING/CONTROLS/A/C HEATER
CONTROL - REMOVAL)
WJCONTROLS 24 - 29
BLOWER MOTOR SWITCH (Continued)

(a) If the refrigerant system fails to reach the
specified vacuum, the system has a leak that must
be corrected. (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING - DIAGNOSIS AND
TESTING - REFRIGERANT SYSTEM LEAKS)
(b) If the refrigerant system maintains the spec-
ified vacuum for five minutes, restart the vacuum
pump, open the suction and discharge valves and
evacuate the system for an additional ten minutes.
(3) Close all of the valves, and turn off the charg-
ing station vacuum pump.
(4) The refrigerant system is now ready to be
charged with R-134a refrigerant. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)
STANDARD PROCEDURE - REFRIGERANT
SYSTEM CHARGE
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
After the refrigerant system has been tested for
leaks and evacuated, a refrigerant charge can be
injected into the system. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - SPECIFICA-
TIONS - CHARGE CAPACITY)
A R-134a refrigerant recovery/recycling/charging
station that meets SAE Standard J2210 must be
used to charge the refrigerant system with R-134a
refrigerant. Refer to the operating instructions sup-
plied by the equipment manufacturer for proper care
and use of this equipment.
PARTIAL CHARGE METHOD
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
The partial charge method is used to add a partial
charge to a refrigerant system that is low on refrig-
erant. To perform this procedure the evaporator inlet
and outlet tube temperatures are measured. The
temperature difference is measured with a tempera-
ture meter with one or two clamp-on thermocouple
probes. The difference between the evaporator inlet
and outlet tube temperatures will determine the
amount of refrigerant needed.Before adding a partial refrigerant charge, check
for refrigerant system leaks. (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING - DIAGNOSIS
AND TESTING - REFRIGERANT SYSTEM LEAKS)
If a leak is found, make the necessary repairs before
attempting a full or partial refrigerant charge.
(1) Attach a manifold gauge set to the refrigerant
system service ports.
(2) Attach the two clamp-on thermocouple probes
to the inlet and outlet tubes of the evaporator coil.
²If a single thermocouple probe is used, attach
the probe to the evaporator inlet tube just before the
collar of the refrigerant line connector fitting. The
probe must make contact with the bottom surface of
the evaporator inlet tube.
²If dual thermocouple probes are used, attach
probe 1 to the evaporator inlet tube, and probe 2 to
the evaporator outlet tube. Attach both probes to the
evaporator tubes just before the collar of the refrig-
erant line connector fittings. The probes must make
contact with the bottom surfaces of the evaporator
inlet and outlet tubes.
(3) Open all of the windows or doors of the passen-
ger compartment.
(4) Set the A/C button on the A/C Heater controls
to the on position, the temperature control knob in
the full cool position, select Recirculation Mode, and
place the blower motor switch in the highest speed
position.
(5) Start the engine and hold the engine idle speed
at 1,000 rpm. Allow the engine to warm up to normal
operating temperature.
(6) The compressor clutch may cycle, depending
upon ambient temperature, humidity, and the refrig-
erant system charge level.
(7) Hold the engine idle speed at 1,000 rpm.
(8) Allow three to five minutes for the refrigerant
system to stabilize, then record the temperatures of
the evaporator inlet and outlet tubes.
²If a single probe is used, record the temperature
of the evaporator inlet tube. Then remove the probe
from the inlet tube and attach it to the evaporator
outlet tube just before the collar of the refrigerant
line connector fitting. The probe must make contact
with the bottom surface of the evaporator outlet tube.
Allow the thermocouple and meter time to stabilize,
then record the temperature of the evaporator outlet
tube. Subtract the inlet tube temperature reading
from the outlet tube temperature reading.
²If dual probes are used, record the temperatures
of both the evaporator inlet and outlet tubes. Then
subtract the inlet tube temperature reading from the
outlet tube temperature reading.
(9) If the measured temperature differential is
higher than 22É C to 26É C (40É F to 47É F), add 0.4
kilograms (14 ounces) of refrigerant.
24 - 56 PLUMBINGWJ
PLUMBING (Continued)

and deteriorate engine performance, driveability and
fuel economy.
The catalyst monitor uses dual oxygen sensors
(O2S's) to monitor the efficiency of the converter. The
dual O2S's sensor strategy is based on the fact that
as a catalyst deteriorates, its oxygen storage capacity
and its efficiency are both reduced. By monitoring
the oxygen storage capacity of a catalyst, its effi-
ciency can be indirectly calculated. The upstream
O2S is used to detect the amount of oxygen in the
exhaust gas before the gas enters the catalytic con-
verter. The PCM calculates the A/F mixture from the
output of the O2S. A low voltage indicates high oxy-
gen content (lean mixture). A high voltage indicates a
low content of oxygen (rich mixture).
When the upstream O2S detects a lean condition,
there is an abundance of oxygen in the exhaust gas.
A functioning converter would store this oxygen so it
can use it for the oxidation of HC and CO. As the
converter absorbs the oxygen, there will be a lack of
oxygen downstream of the converter. The output of
the downstream O2S will indicate limited activity in
this condition.
As the converter loses the ability to store oxygen,
the condition can be detected from the behavior of
the downstream O2S. When the efficiency drops, no
chemical reaction takes place. This means the con-
centration of oxygen will be the same downstream as
upstream. The output voltage of the downstream
O2S copies the voltage of the upstream sensor. The
only difference is a time lag (seen by the PCM)
between the switching of the O2S's.
To monitor the system, the number of lean-to-rich
switches of upstream and downstream O2S's is
counted. The ratio of downstream switches to
upstream switches is used to determine whether the
catalyst is operating properly. An effective catalyst
will have fewer downstream switches than it has
upstream switches i.e., a ratio closer to zero. For a
totally ineffective catalyst, this ratio will be one-to-
one, indicating that no oxidation occurs in the device.
The system must be monitored so that when cata-
lyst efficiency deteriorates and exhaust emissions
increase to over the legal limit, the MIL will be illu-
minated.
DESCRIPTION - TRIP DEFINITION
The term ªTripº has different meanings depending
on what the circumstances are. If the MIL (Malfunc-
tion Indicator Lamp) is OFF, a Trip is defined as
when the Oxygen Sensor Monitor and the Catalyst
Monitor have been completed in the same drive cycle.
When any Emission DTC is set, the MIL on the
dash is turned ON. When the MIL is ON, it takes 3
good trips to turn the MIL OFF. In this case, itdepends on what type of DTC is set to know what a
ªTripº is.
For the Fuel Monitor or Mis-Fire Monitor (contin-
uous monitor), the vehicle must be operated in the
ªSimilar Condition Windowº for a specified amount of
time to be considered a Good Trip.
If a Non-Contiuous OBDII Monitor fails twice in a
row and turns ON the MIL, re-running that monitor
which previously failed, on the next start-up and
passing the monitor, is considered to be a Good Trip.
These will include the following:
²Oxygen Sensor
²Catalyst Monitor
²Purge Flow Monitor
²Leak Detection Pump Monitor (if equipped)
²EGR Monitor (if equipped)
²Oxygen Sensor Heater Monitor
If any other Emission DTC is set (not an OBDII
Monitor), a Good Trip is considered to be when the
Oxygen Sensor Monitor and Catalyst Monitor have
been completed; or 2 Minutes of engine run time if
the Oxygen Sensor Monitor or Catalyst Monitor have
been stopped from running.
It can take up to 2 Failures in a row to turn on the
MIL. After the MIL is ON, it takes 3 Good Trips to
turn the MIL OFF. After the MIL is OFF, the PCM
will self-erase the DTC after 40 Warm-up cycles. A
Warm-up cycle is counted when the ECT (Engine
Coolant Temperature Sensor) has crossed 160ÉF and
has risen by at least 40ÉF since the engine has been
started.
DESCRIPTION - COMPONENT MONITORS
There are several components that will affect vehi-
cle emissions if they malfunction. If one of these com-
ponents malfunctions the Malfunction Indicator
Lamp (MIL) 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 if
the TPS indicates a small throttle opening.
All open/short circuit checks or any component that
has an associated limp in will set a fault after 1 trip
with the malfunction present. Components without
WJEMISSIONS CONTROL 25 - 19
EMISSIONS CONTROL (Continued)

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 within  375
RPM and load is within  10% 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:
²Specific 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 CyclesSpecific Good Trip
The term Good Trip has different meanings
depending on the circumstances:
²If the MIL is OFF, a trip is defined as when the
Oxygen Sensor Monitor and the Catalyst Monitor
have been completed in the same drive cycle.
²If the MIL is ON and a DTC was set by the Fuel
Monitor or Misfire Monitor (both continuous moni-
tors), the vehicle must be operated in the Similar
Condition Window for a specified amount of time.
²If the MIL is ON and a DTC was set by a Task
Manager commanded once-per-trip monitor (such as
the Oxygen Sensor Monitor, Catalyst Monitor, Purge
Flow Monitor, Leak Detection Pump Monitor, EGR
Monitor or Oxygen Sensor Heater Monitor), a good
trip is when the monitor is passed on the next start-
up.
²If the MIL is ON and any other emissions DTC
was set (not an OBD II monitor), a good trip occurs
when the Oxygen Sensor Monitor and Catalyst Mon-
itor have been completed, or two minutes of engine
run time if the Oxygen Sensor Monitor and Catalyst
Monitor have been stopped from running.
Fuel System Good Trip
To count a good trip (three required) and turn off
the MIL, the following conditions must occur:
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
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
25 - 22 EMISSIONS CONTROLWJ
EMISSIONS CONTROL (Continued)

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 two
trip 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 utilizes
both Short Term Compensation and Long Term Adap-
tive 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 thePCM 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.
MISFIRE
²Same Misfire Warm-Up StateÐ Indicates if
the misfire occurred when the engine was warmed up
(above 160É F).
²In Similar Misfire WindowÐ An indicator
that 'Absolute MAP When Misfire Occurred' and
'RPM When Misfire Occurred' are all in the same
range when the failure occurred. Indicated by switch-
ing from 'NO' to 'YES'.
²Absolute MAP When Misfire OccurredÐ
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 Misfire OccurredÐ 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 utilizes
both Short Term Compensation and Long Term Adap-
tive to calculate the Adaptive Memory Factor for
total fuel correction.
²200 Rev CounterÐ Counts 0±100 720 degree
cycles.
²SCW Cat 200 Rev CounterÐ Counts when in
similar conditions.
²SCW FTP 1000 Rev CounterÐ Counts 0±4
when in similar conditions.
²Misfire Good Trip CounterÐ Counts up to
three to turn OFF the MIL.
²Misfire DataÐ Data collected during test.
²Test Done This TripÐ Indicates YES when the
test is done.
WJEMISSIONS CONTROL 25 - 23
EMISSIONS CONTROL (Continued)