OPERATIONÐThe Oxygen Sensor Heater Moni-
tor begins after the ignition has been turned OFF.
The PCM sends a 5 volt bias to the oxygen sensor
every 1.6 seconds. The PCM keeps it biased for 35
ms each time. As the sensor cools down, the resis-
tance increases and the PCM reads the increase in
voltage. Once voltage has increased to a predeter-
mined amount, higher than when the test started,
the oxygen sensor is cool enough to test heater oper-
ation.
When the oxygen sensor is cool enough, the PCM
energizes the ASD relay. Voltage to the O2 sensor
begins to increase the temperature. As the sensor
temperature increases, the internal resistance
decreases. The PCM continues biasing the 5 volt sig-
nal to the sensor. Each time the signal is biased, the
PCM reads a voltage decrease. When the PCM
detects a voltage decrease of a predetermined value
for several biased pulses, the test passes.
The heater elements are tested each time the
engine is turned OFF if all the enabling conditions
are met. If the monitor fails, the PCM stores a
maturing fault and a Freeze Frame is entered. If two
consecutive tests fail, a DTC is stored. Because the
ignition is OFF, the MIL is illuminated at the begin-
ning of the next key cycle.
Enabling ConditionsÐThe following conditions
must be met for the PCM to run the oxygen sensor
heater test:
²Engine run time of at least 3 minutes
²Engine run time at a predetermined speed
and throttle opening.
²Key OFF power down
²Battery voltage of at least 10 volts
²Sufficient Oxygen Sensor cool down
Pending ConditionsÐThere are not conditions or
situations that prompt conflict or suspension of test-
ing. The oxygen sensor heater test is not run pending
resolution of MIL illumination due to oxygen sensor
failure.
SuspendÐThere are no conditions which exist for
suspending the Heater Monitor.
CATALYST 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.
Normal vehicle miles or engine misfire can cause a
catalyst to decay. A meltdown of the ceramic core can
cause a reduction of the exhaust passage. This can
increase vehicle emissions 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 strategy is based on the fact that as a cat-alyst deteriorates, its oxygen storage capacity and its
efficiency are both reduced. By monitoring the oxy-
gen storage capacity of a catalyst, its efficiency 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 converter. The
PCM calculates the A/F mixture from the output of
the O2S. A low voltage indicates high oxygen 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 (check
engine lamp) will be illuminated.
Monitor OperationÐTo monitor catalyst effi-
ciency, the PCM expands the rich and lean switch
points of the heated oxygen sensor. With extended
switch points, the air/fuel mixture runs richer and
leaner to overburden the catalytic converter. Once
the test is started, the air/fuel mixture runs rich and
lean and the O2 switches are counted. A switch is
counted when an oxygen sensor signal goes from
below the lean threshold to above the rich threshold.
The number of Rear O2 sensor switches is divided by
the number of Front O2 sensor switches to determine
the switching ratio.
The test runs for 20 seconds. As catalyst efficiency
deteriorated over the life of the vehicle, the switch
rate at the downstream sensor approaches that of the
upstream sensor. If at any point during the test
25 - 4 EMISSIONS CONTROLRS
EMISSIONS CONTROL (Continued)
ProCarManuals.com
period the switch ratio reaches a predetermined
value, a counter is incremented by one. The monitor
is enabled to run another test during that trip. When
the test fails 6 times, the counter increments to 3, a
malfunction is entered, and a Freeze Frame is stored,
the code is matured and the MIL is illuminated. If
the first test passes, no further testing is conducted
during that trip.
The MIL is extinguished after three consecutive
good trips. The good trip criteria for the catalyst
monitor is more stringent than the failure criteria. In
order to pass the test and increment one good trip,
the downstream sensor switch rate must be less than
45% of the upstream rate. The failure percentages
are 59% respectively.
Enabling ConditionsÐThe following conditions
must typically be met before the PCM runs the cat-
alyst monitor. Specific times for each parameter may
be different from engine to engine.
²Accumulated drive time
²Enable time
²Ambient air temperature
²Barometric pressure
²Catalyst warm-up counter
²Engine coolant temperature
²Vehicle speed
²MAP
²RPM
²Engine in closed loop
²Fuel level
Pending ConditionsÐ
²Misfire DTC
²Front Oxygen Sensor Response
²Front Oxygen Sensor Heater Monitor
²Front Oxygen Sensor Electrical
²Rear Oxygen Sensor Rationality (middle check)
²Rear Oxygen Sensor Heater Monitor
²Rear Oxygen Sensor Electrical
²Fuel System Monitor
²All TPS faults
²All MAP faults
²All ECT sensor faults
²Purge flow solenoid functionality
²Purge flow solenoid electrical
²All PCM self test faults
²All CMP and CKP sensor faults
²All injector and ignition electrical faults
²Idle Air Control (IAC) motor functionality
²Vehicle Speed Sensor
²Brake switch (auto trans only)
²Intake air temperature
ConflictÐThe catalyst monitor does not run if any
of the following are conditions are present:
²EGR Monitor in progress (if equipped)
²Fuel system rich intrusive test in progress
²EVAP Monitor in progress²Time since start is less than 60 seconds
²Low fuel level-less than 15 %
²Low ambient air temperature
²Ethanol content learn is taking place and the
ethanol used once flag is set
SuspendÐThe Task Manager does not mature a
catalyst fault if any of the following are present:
²Oxygen Sensor Monitor, Priority 1
²Oxygen Sensor Heater, Priority 1
²EGR Monitor, Priority 1 (if equipped)
²EVAP Monitor, Priority 1
²Fuel System Monitor, Priority 2
²Misfire Monitor, Priority 2
OPERATION - NON-MONITORED CIRCUITS
The PCM does not monitor all circuits, systems
and conditions that could have malfunctions causing
driveability problems. However, problems with these
systems may cause the PCM to store diagnostic trou-
ble codes for other systems or components. For exam-
ple, a fuel pressure problem will not register a fault
directly, but could cause a rich/lean condition or mis-
fire. This could cause the PCM to store an oxygen
sensor or misfire diagnostic trouble code.
The major non-monitored circuits are listed below
along with examples of failures modes that do not
directly cause the PCM to set a DTC, but for a sys-
tem that is monitored.
FUEL PRESSURE
The fuel pressure regulator controls fuel system
pressure. The PCM cannot detect a clogged fuel
pump inlet filter, clogged in-line fuel filter, or a
pinched fuel supply or return line. However, these
could result in a rich or lean condition causing the
PCM to store an oxygen sensor, fuel system, or mis-
fire diagnostic trouble code.
SECONDARY IGNITION CIRCUIT
The PCM cannot detect an inoperative ignition coil,
fouled or worn spark plugs, ignition cross firing, or
open spark plug cables. The misfire will however,
increase the oxygen content in the exhaust, deceiving
the PCM in to thinking the fuel system is too lean.
Also see misfire detection.
CYLINDER COMPRESSION
The PCM cannot detect uneven, low, or high engine
cylinder compression. Low compression lowers O2
content in the exhaust. Leading to fuel system, oxy-
gen sensor, or misfire detection fault.
EXHAUST SYSTEM
The PCM cannot detect a plugged, restricted or
leaking exhaust system. It may set a EGR (if
equipped) or Fuel system or O2S fault.
RSEMISSIONS CONTROL25-5
EMISSIONS CONTROL (Continued)
ProCarManuals.com
FUEL INJECTOR MECHANICAL MALFUNCTIONS
The PCM cannot determine if a fuel injector is
clogged, the needle is sticking or if the wrong injector
is installed. However, these could result in a rich or
lean condition causing the PCM to store a diagnostic
trouble code for either misfire, an oxygen sensor, or
the fuel system.
EXCESSIVE OIL CONSUMPTION
Although the PCM monitors engine exhaust oxygen
content when the system is in closed loop, it cannot
determine excessive oil consumption.
THROTTLE BODY AIR FLOW
The PCM cannot detect a clogged or restricted air
cleaner inlet or filter element.
VACUUM ASSIST
The PCM cannot detect leaks or restrictions in the
vacuum circuits of vacuum assisted engine control
system devices. However, these could cause the PCM
to store a MAP sensor diagnostic trouble code and
cause a high idle condition.
PCM SYSTEM GROUND
The PCM cannot determine a poor system ground.
However, one or more diagnostic trouble codes may
be generated as a result of this condition. The mod-
ule should be mounted to the body at all times,
including when diagnostics are performed.
PCM CONNECTOR ENGAGEMENT
The PCM may not be able to determine spread or
damaged connector pins. However, it might store
diagnostic trouble codes as a result of spread connec-
tor pins.
DESCRIPTION - MONITORED SYSTEMS
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 a DRBIIItscan tool.
The following is a list of the system monitors:
²EGR Monitor (if equipped)²Misfire Monitor
²Fuel System Monitor
²Oxygen Sensor Monitor
²Oxygen Sensor Heater Monitor
²Catalyst Monitor
²Evaporative System Leak Detection Monitor (if
equipped)
Following is a description of each system monitor,
and its DTC.
Refer to the appropriate Powertrain Diagnos-
tics Procedures manual for diagnostic proce-
dures.
OXYGEN SENSOR (O2S) MONITOR
Effective control of exhaust emissions is achieved
by an oxygen feedback system. The most important
element of the feedback system is the O2S. The O2S
is located in the exhaust path. Once it reaches oper-
ating temperatures of 300É to 350ÉC (572É to 662ÉF),
the sensor generates a voltage that is inversely pro-
portional to the amount of oxygen in the exhaust.
The information obtained by the sensor is used to
calculate the fuel injector pulse width. The PCM is
programmed to maintain the optimum air/fuel ratio.
At this mixture ratio, the catalyst works best to
remove hydrocarbons (HC), carbon monoxide (CO)
and nitrous oxide (NOx) from the exhaust.
The O2S is also the main sensing element for the
EGR (if equipped), Catalyst and Fuel Monitors.
The O2S may fail in any or all of the following
manners:
²Slow response rate
²Reduced output voltage
²Dynamic shift
²Shorted or open circuits
Response rate is the time required for the sensor to
switch from lean to rich once it is exposed to a richer
than optimum A/F mixture or vice versa. As the sen-
sor starts malfunctioning, it could take longer to
detect the changes in the oxygen content of the
exhaust gas.
The output voltage of the O2S ranges from 0 to 1
volt (voltages are offset by 2.5 volts on NGC vehi-
cles). A good sensor can easily generate any output
voltage in this range as it is exposed to different con-
centrations of oxygen. To detect a shift in the A/F
mixture (lean or rich), the output voltage has to
change beyond a threshold value. A malfunctioning
sensor could have difficulty changing beyond the
threshold value.
OXYGEN SENSOR HEATER MONITOR
If there is an oxygen sensor (O2S) DTC as well as
a O2S heater DTC, the O2S heater fault MUST be
repaired first. After the O2S fault is repaired, verify
that the heater circuit is operating correctly.
25 - 6 EMISSIONS CONTROLRS
EMISSIONS CONTROL (Continued)
ProCarManuals.com
Effective control of exhaust emissions is achieved
by an oxygen feedback system. The most important
element of the feedback system is the O2S. The O2S
is located in the exhaust path. Once it reaches oper-
ating temperatures of 300É to 350ÉC (572 É to 662ÉF),
the sensor generates a voltage that is inversely pro-
portional to the amount of oxygen in the exhaust.
The information obtained by the sensor is used to
calculate the fuel injector pulse width. This main-
tains a 14.7 to 1 Air Fuel (A/F) ratio. At this mixture
ratio, the catalyst works best to remove hydrocarbons
(HC), carbon monoxide (CO) and nitrogen oxide
(NOx) from the exhaust.
The voltage readings taken from the O2S are very
temperature sensitive. The readings are not accurate
below 300ÉC. Heating of the O2S is done to allow the
engine controller to shift to closed loop control as
soon as possible. The heating element used to heat
the O2S must be tested to ensure that it is heating
the sensor properly.
The O2S circuit is monitored for a drop in voltage.
The sensor output is used to test the heater by iso-
lating the effect of the heater element on the O2S
output voltage from the other effects.
EGR MONITOR (if equipped)
The Powertrain Control Module (PCM) performs
an on-board diagnostic check of the EGR system.
The EGR monitor is used to test whether the EGR
system is operating within specifications. The diag-
nostic 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 monitored. Turning off the
EGR shifts the air fuel (A/F) ratio in the lean direc-
tion. The O2S data should indicate an increase in the
O2 concentration in the combustion chamber when
the exhaust gases are no longer recirculated. 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. Also
looks at EGR linear potentiometer for feedback.
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.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.
The PCM is programmed to maintain the optimum
air/fuel ratio. This is done by making short term cor-
rections in the fuel injector pulse width based on the
O2S output. The programmed memory acts as a self
calibration tool that the engine controller uses to
compensate for variations in engine specifications,
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 multiplying that
with the program long-term (adaptive) memory and
comparing that to the limit, it can be determined
whether it will pass an emissions test. If a malfunc-
tion occurs such that the PCM cannot maintain the
optimum A/F ratio, then the MIL will be illuminated.
CATALYST 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.
Normal vehicle miles or engine misfire can cause a
catalyst to decay. A meltdown of the ceramic core can
cause a reduction of the exhaust passage. This can
increase vehicle emissions 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 strategy is based on the fact that as a cat-
alyst deteriorates, its oxygen storage capacity and its
efficiency are both reduced. By monitoring the oxy-
gen storage capacity of a catalyst, its efficiency 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 converter. The
PCM calculates the A/F mixture from the output of
the O2S. A low voltage indicates high oxygen 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
RSEMISSIONS CONTROL25-7
EMISSIONS CONTROL (Continued)
ProCarManuals.com
OPERATION
OPERATION - SYSTEM
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
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 DRBIIITscan tool
to erase all DTC's and extinguish the MIL.Technicians can display stored DTC's. Refer to
Diagnostic Trouble Codes (Refer to 8 - ELECTRICAL/
ELECTRONIC CONTROL MODULES/POWER-
TRAIN CONTROL MODULE - DESCRIPTION). For
obtaining the DTC information, use the Data Link
Connector with the DRBIIItscan tool (Fig. 1).
DRB IIITSTATE DISPLAY TEST MODE
OPERATION
The switch inputs to the Powertrain Control Mod-
ule (PCM) have two recognized states; HIGH and
LOW. For this reason, the PCM cannot recognize the
difference between a selected switch position versus
an open circuit, a short circuit, or a defective switch.
If the State Display screen shows the change from
HIGH to LOW or LOW to HIGH, assume the entire
switch circuit to the PCM functions properly. From
the state display screen, access either State Display
Inputs and Outputs or State Display Sensors.
Fig. 1 Data Link Connector
RSEMISSIONS CONTROL25-9
EMISSIONS CONTROL (Continued)
ProCarManuals.com
De-energizing the solenoid, but not fully closing the
transducer bleed hole (because of low back-pressure),
varies the strength of vacuum applied to the EGR
valve. Varying the strength of the vacuum changes
the amount of EGR supplied to the engine. This pro-
vides the correct amount of exhaust gas recirculation
for different operating conditions.
This system does not allow EGR at idle.
A failed or malfunctioning EGR system can cause
engine spark knock, sags or hesitation, rough idle,
engine stalling and increased emissions.
REMOVAL - 2.4L
The EGR valve and Electrical EGR Transducer are
serviced as an assembly (Fig. 1).
(1) Disconnect vacuum tube from electric EGR
transducer. Inspect vacuum tube for damage.
(2) Remove electrical connector from solenoid.
(3) Remove EGR tube bolts from EGR valve.
(4) Remove EGR valve from cylinder head adaptor.
(5) Clean gasket surface and discard old gasket.
Check for any signs of leakage or cracked surfaces.
Repair or replace as necessary.
INSTALLATION - 2.4L
The EGR valve and Electrical EGR Transducer are
serviced as an assembly (Fig. 1).
(1) Assemble EGR valve with new gasket onto the
cylinder head adaptor.
(2) Loose assemble the bolts from EGR valve to
EGR tube.
(3) Loose assemble the bolts from EGR valve to
cylinder head.
(4) Tighten bolts from EGR valve to cylinder head
to 22.8 N´m (200 25 in. lbs.) torque.
(5) Tighten bolts from EGR valve to EGR tube to
11.9 N´m (105 20 in. lbs.) torque.
(6) Reconnect vacuum hose and electrical connec-
tor to electrical EGR transducer.
RSEXHAUST GAS RECIRCULATION25-23
VALVE (Continued)
ProCarManuals.com
ON-BOARD DIAGNOSTICS
TABLE OF CONTENTS
page page
TASK MANAGER
DESCRIPTION.........................24OPERATION...........................24
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 ªTask Managerº.
OPERATION
The Task Manager determines when tests happen
and when functions occur. Many of the diagnostic
steps required by OBD II must be performed under
specific operating conditions. The Task Manager soft-
ware organizes and prioritizes the diagnostic proce-
dures. The job of the Task Manager is to determine if
conditions are appropriate for tests to be run, moni-
tor the parameters for a trip for each test, and record
the results of the test. Following are the responsibil-
ities 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 known 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 notrun 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 catalyst
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
that may induce an erroneous failure. This prevents
illuminating the MIL for the wrong fault and allows
more precise diagnosis.
For example, if the PCM is storing a one trip fault
for the Oxygen Sensor and the catalyst monitor, the
Task Manager may still run the catalyst 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 catalyst system is
actually 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.
25 - 24 ON-BOARD DIAGNOSTICSRS
ProCarManuals.com
ABS FASTENER TORQUE,
SPECIFICATIONS......................5-79
ABSORBER - DESCRIPTION, SHOCK.......2-36
ABSORBER - INSTALLATION, SHOCK......2-38
ABSORBER - OPERATION, SHOCK........2-36
ABSORBER - REMOVAL, SHOCK..........2-36
ABSORBER (UPPER BUSHING) -
ASSEMBLY, SHOCK....................2-37
ABSORBER (UPPER BUSHING) -
DISASSEMBLY, SHOCK.................2-36
A/C COMPRESSOR - DESCRIPTION......24-63
A/C COMPRESSOR - OPERATION........24-63
A/C COOL DOWN TEST - DIAGNOSIS
AND TESTING........................24-4
A/C DISTRIBUTION DUCT -
INSTALLATION.......................24-53
A/C DISTRIBUTION DUCT - REMOVAL....24-53
A/C HEATER CONTROL - INSTALLATION....24-9
A/C HEATER CONTROL - REMOVAL.......24-9
A/C PERFORMANCE TEST - DIAGNOSIS
AND TESTING........................24-5
A/C PLUMBING - CAUTION.............24-61
A/C PLUMBING - WARNING............24-61
A/C PRESSURE TRANSDUCER -
DESCRIPTION.......................24-10
A/C PRESSURE TRANSDUCER -
DIAGNOSIS AND TESTING.............24-10
A/C PRESSURE TRANSDUCER -
INSTALLATION.......................24-11
A/C PRESSURE TRANSDUCER -
OPERATION.........................24-10
A/C PRESSURE TRANSDUCER -
REMOVAL..........................24-10
ACCELERATOR PEDAL - INSTALLATION . . . 14-24
ACCELERATOR PEDAL - REMOVAL.......14-23
ACCESSORY DRIVE BELT - DIAGNOSIS
AND TESTING.........................7-7
ACCESSORY DRIVE BELT TENSION,
SPECIFICATIONS.......................7-5
ACCESSORY RELAY - DESCRIPTION . . . 8W-97-2
ACCESSORY RELAY - DIAGNOSIS &
TESTING.........................8W-97-2
ACCESSORY RELAY - OPERATION.....8W-97-2
ACCUMULATOR - DESCRIPTION........21-188
ACCUMULATOR - OPERATION..........21-189
A/C-HEATER CONTROL - INSTALLATION . . . 24-29
A/C-HEATER CONTROL - REMOVAL......24-29
ACTUATOR - DESCRIPTION, BLEND
DOOR........................24-11,24-30
ACTUATOR - DESCRIPTION, ENGAGE.....8N-10
ACTUATOR - DESCRIPTION, LATCH......8N-14
ACTUATOR - DESCRIPTION, MODE
DOOR.............................24-24
ACTUATOR - DESCRIPTION,
RECIRCULATION DOOR................24-27
ACTUATOR - INSTALLATION, BLEND
DOOR........................24-12,24-31
ACTUATOR - INSTALLATION, ENGAGE....8N-11
ACTUATOR - INSTALLATION, LATCH.....8N-14
ACTUATOR - INSTALLATION, MODE
DOOR........................24-25,24-36
ACTUATOR - INSTALLATION,
RECIRCULATION DOOR................24-28
ACTUATOR - OPERATION, BLEND DOOR . . 24-11,
24-30
ACTUATOR - OPERATION, ENGAGE......8N-11
ACTUATOR - OPERATION, LATCH........8N-14
ACTUATOR - OPERATION, MODE DOOR . . . 24-24
ACTUATOR - OPERATION,
RECIRCULATION DOOR................24-27
ACTUATOR - REMOVAL, BLEND DOOR . . . 24-12,
24-31
ACTUATOR - REMOVAL, ENGAGE........8N-11
ACTUATOR - REMOVAL, LATCH.........8N-14
ACTUATOR - REMOVAL, MODE DOOR....24-25,
24-36
ACTUATOR - REMOVAL, RECIRCULATION
DOOR.............................24-27
ADAPTER - INSTALLATION, FRONT DISC
BRAKE CALIPER......................5-31
ADAPTER - INSTALLATION, OIL FILTER
. . . 9-139
ADAPTER - REMOVAL, FRONT DISC
BRAKE CALIPER
......................5-31
ADAPTER - REMOVAL, OIL FILTER
.......9-139
ADAPTIVE MEMORIES, OPERATION -
FUEL CORRECTION OR
................14-20
ADDING ADDITIONAL COOLANT -
STANDARD PROCEDURE
.................7-5ADDITIONAL COOLANT - STANDARD
PROCEDURE, ADDING...................7-5
ADHESIVE ATTACHED - INSTALLATION,
EXTERIOR NAME PLATES..............23-50
ADHESIVE ATTACHED - REMOVAL,
EXTERIOR NAME PLATES..............23-50
ADHESIVE LOCATIONS -
SPECIFICATIONS, STRUCTURAL........23-153
ADJUSTER-BORC-PILLAR -
INSTALLATION, SEAT BELT HEIGHT......8O-12
ADJUSTER-BORC-PILLAR -
REMOVAL, SEAT BELT HEIGHT..........8O-12
ADJUSTER - DIAGNOSIS AND TESTING,
DRUM BRAKE AUTOMATIC..............5-13
ADJUSTER - INSTALLATION, FRONT
SEAT TRACK MANUAL................23-94
ADJUSTER - INSTALLATION, FRONT
SEAT TRACK POWER.................23-94
ADJUSTER - REMOVAL, FRONT SEAT
TRACK MANUAL.....................23-94
ADJUSTER - REMOVAL, FRONT SEAT
TRACK POWER......................23-94
ADJUSTER KNOB - INSTALLATION, SEAT
BELT HEIGHT.......................8O-13
ADJUSTER KNOB - REMOVAL, SEAT
BELT HEIGHT.......................8O-13
ADJUSTER NOISE DIAGNOSIS -
DIAGNOSIS AND TESTING, HYDRAULIC
LASH...............................9-34
ADJUSTER TENSION RELEASE -
STANDARD PROCEDURE, PARKING
BRAKE AUTOMATIC....................5-58
ADJUSTER TENSION RESET -
STANDARD PROCEDURE, PARKING
BRAKE AUTOMATIC.....................5-59
ADJUSTERS - INSTALLATION,
HYDRAULIC LASH.....................9-34
ADJUSTERS - REMOVAL, HYDRAULIC
LASH...............................9-34
AERATION - DIAGNOSIS AND TESTING,
COOLING SYSTEM.....................7-3
AFTER AN AIRBAG DEPLOYMENT -
STANDARD PROCEDURE, SERVICE.......8O-3
AIR CLEANER ELEMENT - INSTALLATION . . 9-24,
9-98
AIR CLEANER ELEMENT - REMOVAL . . 9-24,9-98
AIR CLEANER HOUSING - INSTALLATION . . 9-24,
9-99
AIR CLEANER HOUSING - REMOVAL . . 9-24,9-99
AIR CONDITIONING LINES -
INSTALLATION, REAR................24-105
AIR CONDITIONING LINES - REMOVAL,
REAR.............................24-104
AIR CONTROL MOTOR - DESCRIPTION,
IDLE...............................14-28
AIR CONTROL MOTOR - INSTALLATION,
IDLE...............................14-29
AIR CONTROL MOTOR - OPERATION,
IDLE...............................14-28
AIR CONTROL MOTOR - REMOVAL, IDLE . . 14-29
AIR EXHAUSTER - DESCRIPTION, REAR
QUARTER PANEL/FENDER..............23-56
AIR EXHAUSTER - INSTALLATION, REAR
QUARTER PANEL/FENDER..............23-57
AIR EXHAUSTER - REMOVAL, REAR
QUARTER PANEL/FENDER..............23-56
AIR FILTER - DESCRIPTION............24-39
AIR FILTER - INSTALLATION............24-40
AIR FILTER - REMOVAL...............24-39
AIR GAP - STANDARD PROCEDURE,
COMPRESSOR CLUTCH...............24-17
AIR GAP, SPECIFICATIONS - WHEEL
SPEED SENSOR.......................5-79
AIR INTAKE PIPE - INSTALLATION......24-113
AIR INTAKE PIPE - REMOVAL..........24-112
AIR OUTLETS - DESCRIPTION.....24-40,24-52
AIR OUTLETS - INSTALLATION..........24-52
AIR OUTLETS - REMOVAL.............24-52
AIR PRESSURE TESTS - DIAGNOSIS
AND TESTING, CLUTCH...............21-122
AIR TEMPERATURE SENSOR -
DESCRIPTION, INLET.................14-29
AIR TEMPERATURE SENSOR -
OPERATION, INLET
...................14-29
AIRBAG - DESCRIPTION, DRIVER
........8O-5
AIRBAG - DESCRIPTION, PASSENGER
.....8O-7
AIRBAG - DESCRIPTION, SEAT
..........8O-10
AIRBAG - INSTALLATION, DRIVER
........8O-6AIRBAG - INSTALLATION, PASSENGER....8O-9
AIRBAG - OPERATION, DRIVER..........8O-5
AIRBAG - OPERATION, PASSENGER.......8O-8
AIRBAG - OPERATION, SEAT...........8O-11
AIRBAG - REMOVAL, DRIVER............8O-5
AIRBAG - REMOVAL, PASSENGER........8O-8
AIRBAG CONTROL MODULE -
DESCRIPTION, SIDE IMPACT...........8O-17
AIRBAG CONTROL MODULE -
INSTALLATION, SIDE IMPACT...........8O-17
AIRBAG CONTROL MODULE -
OPERATION, SIDE IMPACT.............8O-17
AIRBAG CONTROL MODULE - REMOVAL,
SIDE IMPACT.......................8O-17
AIRBAG DEPLOYMENT - STANDARD
PROCEDURE, SERVICE AFTER AN........8O-3
AIRBAG SYSTEM - DIAGNOSIS AND
TESTING............................8O-2
AIRBAG TRIM COVER - INSTALLATION,
DRIVER.............................8O-7
AIRBAG TRIM COVER - REMOVAL,
DRIVER.............................8O-6
AIRBAGS - STANDARD PROCEDURE,
HANDLING..........................8O-3
AJAR SWITCH - EXPORT -
INSTALLATION, HOOD.................8Q-3
AJAR SWITCH - EXPORT - REMOVAL,
HOOD..............................8Q-3
ALIGNMENT - DESCRIPTION, WHEEL......2-46
ALIGNMENT - EXPORT - STANDARD
PROCEDURE, FRONT FOG LAMP UNIT.....8L-9
ALIGNMENT - EXPORT - STANDARD
PROCEDURE, HEADLAMP UNIT.........8L-17
ALIGNMENT - STANDARD PROCEDURE,
FRONT FOG LAMP UNIT................8L-9
ALIGNMENT - STANDARD PROCEDURE,
FRONT WIPER ARM...................8R-8
ALIGNMENT - STANDARD PROCEDURE,
HEADLAMP UNIT.....................8L-17
ALIGNMENT - STANDARD PROCEDURE,
WHEEL.............................2-51
ALIGNMENT, SPECIFICATIONS - WHEEL....2-55
ALUMINUM WHEEL CARE - CLEANING . . . 22-18
AMBIENT TEMP SENSOR - DESCRIPTION . 8M-11
AMBIENT TEMP SENSOR - OPERATION . . 8M-11
AMBIENT TEMPERATURE SENSOR -
DIAGNOSIS AND TESTING.............8M-12
AMBIENT TEMPERATURE SENSOR
CIRCUIT - DIAGNOSIS AND TESTING....8M-12
AN AIRBAG DEPLOYMENT - STANDARD
PROCEDURE, SERVICE AFTER...........8O-3
ANTENNA - EXPORT - DESCRIPTION,
QUARTER GLASS INTEGRAL............8A-9
ANTENNA - EXPORT - DIAGNOSIS AND
TESTING, QUARTER GLASS INTEGRAL....8A-9
ANTENNA - EXPORT - OPERATION,
QUARTER GLASS INTEGRAL............8A-9
ANTENNA BODY AND CABLE -
DESCRIPTION........................8A-4
ANTENNA BODY AND CABLE -
DIAGNOSIS AND TESTING..............8A-4
ANTENNA BODY AND CABLE -
INSTALLATION.......................8A-6
ANTENNA BODY AND CABLE -
OPERATION..........................8A-4
ANTENNA BODY AND CABLE - REMOVAL . . 8A-5
ANTENNA CABLE - INSTALLATION,
INSTRUMENT PANEL..................8A-9
ANTENNA CABLE - REMOVAL,
INSTRUMENT PANEL..................8A-8
ANTENNA MODULE - EXPORT -
DESCRIPTION........................8A-6
ANTENNA MODULE - EXPORT -
DIAGNOSIS AND TESTING..............8A-7
ANTENNA MODULE - EXPORT -
INSTALLATION.......................8A-7
ANTENNA MODULE - EXPORT -
OPERATION..........................8A-6
ANTENNA MODULE - EXPORT -
REMOVAL
...........................8A-7
ANTILOCK BRAKE - DESCRIPTION,
CONTROLLER
........................8E-5
ANTILOCK BRAKE - INSTALLATION,
CONTROLLER
........................8E-6
ANTILOCK BRAKE - OPERATION,
CONTROLLER
........................8E-5
ANTILOCK BRAKE - REMOVAL,
CONTROLLER
........................8E-6
RSINDEX1
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