catalytic converter CHRYSLER CARAVAN 2003 User Guide

The combustion reaction caused by the catalyst
releases additional heat in the exhaust system, caus-
ing temperature increases in the area of the reactor
under severe operating conditions. Such conditions
can exist when the engine misfires or otherwise does
not operate at peak efficiency.Do notremove spark
plug wires from plugs or by any other means short
out cylinders, if exhaust system is equipped with a
catalytic converter. Failure of the catalytic converter
can occur due to temperature increases caused by
unburned fuel passing through the converter. This
deterioration of the catalyst core can result in exces-
sively high emission levels, noise complaints, and
exhaust restrictions.
Unleaded gasoline must be used to avoid ruining
the catalyst core. Do not allow engine to operate
above 1200 RPM in neutral for extended periods over
5 minutes. This condition may result in excessive
exhaust system/floor pan temperatures because of no
air movement under the vehicle.
The flex joint allows flexing as the engine moves,
preventing breakage that could occur from the back-
and-forth motion of a transverse mounted engine.
CAUTION: Due to exterior physical similarities of
some catalytic converters with pipe assemblies,
extreme care should be taken with replacement
parts. There are internal converter differences
required in some parts of the country (particularly
vehicles built for States with strict emission
requirements) and between model years.
REMOVAL
(1) Loosen clamp and disconnect the muffler/reso-
nator assembly from catalytic converter pipe.
(2) Disconnect downstream oxygen sensor electri-
cal connector (Fig. 4). For removal of downstream
oxygen sensor, (Refer to 14 - FUEL SYSTEM/FUEL
INJECTION/O2 SENSOR - REMOVAL).
(3) Remove catalytic converter to exhaust manifold
attaching fasteners (Fig. 5).
(4) Remove catalytic converter and gasket (Fig. 5).
INSPECTION
WARNING: THE NORMAL OPERATING TEMPERA-
TURE OF THE EXHAUST SYSTEM IS VERY HIGH.
THEREFORE, NEVER ATTEMPT TO SERVICE ANY
PART OF THE EXHAUST SYSTEM UNTIL IT IS
COOLED. SPECIAL CARE SHOULD BE TAKEN
WHEN WORKING NEAR THE CATALYTIC CON-
VERTER. THE TEMPERATURE OF THE CONVERTER
RISES TO A HIGH LEVEL AFTER A SHORT PERIOD
OF ENGINE OPERATION TIME.Check catalytic converter for a flow restriction.
(Refer to 11 - EXHAUST SYSTEM - DIAGNOSIS
AND TESTING) Exhaust System Restriction Check
for procedure.
Fig. 4 Downstream Oxygen Sensor
1 - OXYGEN SENSOR CONNECTOR
2 - CATALYTIC CONVERTER
3 - DOWNSTREAM OXYGEN SENSOR
4 - ENGINE HARNESS CONNECTOR
Fig. 5 Catalytic Converter to Exhaust Manifold
1 - FLAG NUT
2 - GASKET
3 - BOLT
4 - CATALYTIC CONVERTER
RSEXHAUST SYSTEM11-5
CATALYTIC CONVERTER (Continued)
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Visually inspect the catalytic converter element by
using a borescope or equivalent. Remove oxygen sen-
sor(s) and insert borescope. If borescope is not avail-
able, remove converter and inspect element using a
flashlight. Inspect element for cracked or melted sub-
strate.
NOTE: Before replacing a catalytic converter, deter-
mine the root cause of failure. Most catalytic con-
verter failures are caused by air, fuel or ignition
problems. (Refer to Appropriate Diagnostic Informa-
tion) for test procedures.
INSTALLATION
(1) Position new gasket onto the manifold flange
and install catalytic converter (Fig. 5). Tighten fas-
teners to 37 N´m (325 in. lbs.).
NOTE: Be careful not to twist or kink the oxygen
sensor wires.
(2) Install (if removed) and connect the down-
stream oxygen sensor (Fig. 4).
(3) Install the muffler/resonator assembly. (Refer
to 11 - EXHAUST SYSTEM/MUFFLER - INSTALLA-
TION)
CROSS-OVER PIPE - 3.3/3.8L
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove the fasteners attaching the left bank
manifold connection to cross-over pipe (Fig. 6).
(3) Raise vehicle and remove the left front wheel.
(4) Access the lower right bank pipe connection
fastener through the left front wheel opening using a
long ratchet extension. Loosen and remove the lower
fastener.
(5) Remove the upper right bank pipe connection
fastener by accessing though the catalytic converter
floor pan tunnel.
(6) Lower the vehicle.
(7) Remove the cross-over pipe (Fig. 6).
(8) Remove gaskets and discard (Fig. 6).
INSTALLATION
(1) Position cross-over pipe to the manifold connec-
tions (Fig. 6).
(2) Position new gasket on left bank (front) pipe
connection and loosely install fasteners (Fig. 6).
(3) Raise the vehicle.
(4) Position new gasket on the right bank pipe con-
nection and install fasteners.
(5) Tighten right bank upper fastener to 41 N´m
(30 ft. lbs.).(6) Tighten right bank lower fastener to 41 N´m
(30 ft. lbs.) using a long ratchet extension accessing
through the left wheel opening.
(7) Install the left front wheel and lower vehicle.
(8) Tighten the left bank pipe connection fasteners
to 41 N´m (30 ft. lbs.) (Fig. 6).
HEAT SHIELDS
DESCRIPTION
The exhaust system heat shields (Fig. 7), (Fig. 8),
or (Fig. 9) are attached to the under body of the vehi-
cle. On vehicles equipped with All Wheel Dive
(AWD), an additional heat shield is mounted to the
catalytic converter.
Fig. 6 CROSS-OVER PIPE
1 - CROSS-OVER PIPE
2 - BOLT
3 - GASKET
4 - FLAG NUT
Fig. 7 CATALYTIC CONVERTER HEAT SHIELD
1 - HEAT SHIELD - CATALYTIC CONVERTER
2 - SCREW (QTY. 4)
11 - 6 EXHAUST SYSTEMRS
CATALYTIC CONVERTER (Continued)
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OPERATION
Heat shields are needed to protect both the vehicle
and the environment from the high temperatures
developed near the catalytic converter.
Avoid application of rust prevention com-
pounds or undercoating materials to exhaust
system floor pan heat shields on cars so
equipped. Light over spray near the edges is
permitted. Application of coating will greatly
reduce the efficiency of the heat shields result-
ing in excessive floor pan temperatures and
objectionable fumes.
REMOVAL
(1) Raise vehicle on hoist.
(2) Remove fasteners attaching applicable heat
shield (Fig. 7), (Fig. 8), or (Fig. 9).
(3) Remove heat shield(s).
INSTALLATION
(1) Position heat shield(s) to underbody.
(2) Install heat shield fasteners and tighten to 2.6
N´m (23 in. lbs.) (Fig. 7), (Fig. 8), or (Fig. 9).
(3) Lower vehicle.
MUFFLER
REMOVAL
(1) Raise vehicle on a body contact type hoist.
NOTE: To provide removal clearance between muf-
fler/resonator pipe and rear axle parts, the rear sus-
pension must be relieved of all body weight.
(2) Apply a penetrating oil to clamp nuts of com-
ponent requiring removal.
CAUTION: When servicing the exhaust system, care
must be exercised not to dent or bend the bellows
of the flex-joint. Should this occur, the flex-joint will
eventually fail, requiring replacement of the cata-
lytic converter.
(3) Disconnect the right side axle half shaft from
the rear differential module (AWD equipped only).
(4) Loosen the band clamp (Fig. 10) at the muffler
to converter pipe connection.
(5) Remove the exhaust hangers to body screws
(Fig. 10).
(6) Separate muffler pipe from converter pipe.
(7) Remove muffler/resonator assembly by moving
assembly forward and guiding the resonator through
the rear axle to body opening.
(8) Clean ends of pipes or muffler to assure mat-
ing of all parts. Discard broken or worn insulators,
rusted clamps, supports and attaching parts.When
replacement is required on any component of
the exhaust system, it is important that original
equipment parts (or equivalent) be used for the
following conditions:
²Ensure proper alignment with other components
in the system.
²Provide acceptable exhaust noise levels.
²Provide proper exhaust system back pressure for
maintaining emission and performance levels.
INSTALLATION
(1) Install the muffler/resonator assembly by guid-
ing resonator between the rear axle and body.
(2) Connect the muffler pipe to the converter pipe
but do not tighten band clamp (Fig. 10).
(3) Position hangers to body and install screws
starting at the resonator working forward (Fig. 10).
Tighten hanger screws to 28 N´m (250 in. lbs.).
Fig. 8 MUFFLER HEAT SHIELD
1 - HEAT SHIELD - MUFFLER
2 - SCREW (QTY. 6)
Fig. 9 RESONATOR PIPE HEAT SHIELD
1 - SCREW (QTY. 3)
2 - HEAT SHIELD - RESONATOR PIPE
3 - MUFFLER
RSEXHAUST SYSTEM11-7
HEAT SHIELDS (Continued)
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(4) Insert muffler pipe into catalytic converter pipe
until the hangers are positioned as shown in (Fig. 11)
CAUTION: Band clamps should never be tightened
such that the two sides of the clamps are bottomed
out against the center hourglass shaped centerblock. Once this occurs, the clamp band has been
stretched and has lost its clamping force and must
be replaced.
To replace the band clamp; remove the nut and peel
back the ends of the clamp until spot weld breaks.
Clean remaining spot weld from the pipe using a
file or grinder until surface is smooth.
NOTE: Maintain proper clamp orientation when
replacing with new clamp.
(5) Tighten the band clamp to 55 N´m (40 ft. lbs.)
(Fig. 12).
(6) Connect the right side half shaft to the rear
differential module (AWD equipped only).
Fig. 10 Exhaust System - Typical (All Vehicles)
1 - SCREW - RESONATOR HANGER TO BODY 3 - MUFFLER & RESONATOR ASSEMBLY
2 - SCREW - MUFFLER HANGER TO BODY 4 - CATALYTIC CONVERTER PIPE
Fig. 11 Exhaust System Alignment
1 - HANGER BRACKET TO BODY
2 - ISOLATOR
3 - HANGER - MUFFLER/RESONATOR SUPPORT
4-6mm(0.25 in.)
Fig. 12 Band Clamp
1 - BAND CLAMP
2 - TORQUE SPECIFICATION
11 - 8 EXHAUST SYSTEMRS
MUFFLER (Continued)
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capacity and converter efficiency. Also, the PCM uses
the upstream heated oxygen sensor input when
adjusting injector pulse width.
When the catalytic converter efficiency drops below
emission standards, the PCM stores a diagnostic
trouble code and illuminates the malfunction indica-
tor lamp (MIL).
The O2 sensors produce voltages from 0 to 1 volt
(this voltage is offset by a constant 2.5 volts on NGC
vehicles), depending upon the oxygen content of the
exhaust gas. When a large amount of oxygen is
present (caused by a lean air/fuel mixture, can be
caused by misfire and exhaust leaks), the sensors
produces a low voltage. When there is a lesser
amount of oxygen present (caused by a rich air/fuel
mixture, can be caused by internal engine problems)it produces a higher voltage. By monitoring the oxy-
gen content and converting it to electrical voltage,
the sensors act as a rich-lean switch.
The oxygen sensors are equipped with a heating
element that keeps the sensors at proper operating
temperature during all operating modes. Maintaining
correct sensor temperature at all times allows the
system to enter into closed loop operation sooner.
Also, it allows the system to remain in closed loop
operation during periods of extended idle.
In Closed Loop operation the PCM monitors the O2
sensors input (along with other inputs) and adjusts
the injector pulse width accordingly. During Open
Loop operation the PCM ignores the O2 sensor input.
The PCM adjusts injector pulse width based on pre-
programmed (fixed) values and inputs from other
sensors.
1.6L Siemens controller and SBEC controller - The
Automatic Shutdown (ASD) relay supplies battery
voltage to both the upstream and downstream heated
oxygen sensors. The oxygen sensors are equipped
with a heating element. The heating elements reduce
the time required for the sensors to reach operating
temperature. The PCM uses pulse width modulation
to control the ground side of the heater to regulate
the temperature on 4 cyl. upstream O2 heater only.
NGC Controller - Has a common ground for the
heater in the O2S. 12 volts is supplied to the heater
in the O2S by the NGC controller. Both the upstream
and downstream O2 sensors for NGC are pulse width
modulation (PWM).
UPSTREAM OXYGEN SENSOR
The input from the upstream heated oxygen sensor
tells the PCM the oxygen content of the exhaust gas.
Fig. 22 O2 SENSOR UPSTREAM 1/1 - 2.4L
Fig. 23 O2 SENSOR UPSTREAM 1/1 - 3.3/3.8L
Fig. 24 O2 SENSOR DOWNSTREAM 1/2 - 2.4/3.3/
3.8L
14 - 32 FUEL INJECTIONRS
O2 SENSOR (Continued)
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on the threads and do not require an additional coat-
ing.
(2) Install sensor and tighten to 27 N´m (20 ft.
lbs.) (Fig. 23).
(3) Connect the electrical connector for the O2 sen-
sor and install onto bracket.
(4) Lower vehicle.
(5) Connect the negative battery cable.
INSTALLATION - UPSTREAM 1/1 - 3.3/3.8L
The engines uses two heated oxygen sensors.(1) After removing the sensor, the exhaust mani-
fold threads must be cleaned with an 18 mm X 1.5 +
6E tap. If reusing the original sensor, coat the sensor
threads with an anti-seize compound such as Loctite
771- 64 or equivalent. New sensors have compound
on the threads and do not require an additional coat-
ing.
(2) Install sensor and tighten to 27 N´m (20 ft.
lbs.).
(3) Connect the electrical connector for the O2 sen-
sor and install onto bracket.
(4) Connect the electrical connector for the speed
control servo.
(5) Install the speed control servo and bracket
refer to the Speed Control Servo for more informa-
tion.
(6) Connect the speed control vacuum harness to
servo.
(7) Install the battery tray, refer to the Battery
section for more information.
(8) Install battery, refer to the Battery section for
more information.
INSTALLATION DOWNSTREAM 2/1 -
2.4/3.3/3.8L
The O2S is located on the side of the catalytic con-
verter.
Threads of new oxygen sensors are factory coated
with anti-seize compound to aid in removal.DO
NOT add any additional anti-seize compound to
the threads of a new oxygen sensor.
(1) Install sensor and tighten to 27 N´m (20 ft.
lbs.).
(2) Connect the electrical connector.
(3) Lower vehicle.
(4) Install the negative battery cable.
THROTTLE BODY
DESCRIPTION
The throttle body is located on the intake manifold
(Fig. 28) or (Fig. 29). Fuel does not enter the intake
manifold through the throttle body. Fuel is sprayed
into the manifold by the fuel injectors.
OPERATION
Filtered air from the air cleaner enters the intake
manifold through the throttle body. The throttle body
contains an air control passage controlled by an Idle
Air Control (IAC) motor. The air control passage is
used to supply air for idle conditions. A throttle valve
(plate) is used to supply air for above idle conditions.
Certain sensors are attached to the throttle body.
The accelerator pedal cable, speed control cable and
Fig. 26 Downstream Oxygen Sensor (1/2)
1 - OXYGEN SENSOR CONNECTOR
2 - CATALYTIC CONVERTER
3 - DOWNSTREAM OXYGEN SENSOR
4 - ENGINE HARNESS CONNECTOR
Fig. 27 DOWNSTREAM 2/1 O2 SENSOR
14 - 34 FUEL INJECTIONRS
O2 SENSOR (Continued)
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REMOVAL
REMOVAL - PUMP (2.4L ENGINE)
(1) Remove the (-) negative battery cable from the
battery and isolate cable.
(2) Remove the cap from the power steering fluid
reservoir.
(3) Using a siphon pump, remove as much power
steering fluid as possible from the power steering
fluid reservoir.
(4) Raise the vehicle on jack stands or centered on
a frame contact type hoist. See Hoisting in Lubrica-
tion and Maintenance.
(5) Disconnect the oxygen sensor wiring harness
from the vehicle wiring harness at the rear engine
mount bracket.
NOTE: The exhaust system needs to be removed
from the engine to allow for an area to remove the
power steering pump from the vehicle.
(6) Remove the four bolts and flag nuts securing
the catalytic converter from the exhaust manifold
(Fig. 3).
(7) Disconnect all the exhaust system isolators/
hangers from the brackets on the exhaust system (2
at the mufflers and 1 at the resonator) (Fig. 4).
(8) Remove the exhaust system by moving it as far
rearward, then lowering the front below the cross-
member and out of the vehicle.
(9) Remove the power steering fluid supply hose
from the fitting on the power steering pump. Drain
off excess power steering fluid from hose.(10) Move the heat sleeve on the power steering
return hose to expose the hose connection at the
pump (Fig. 5). Remove the hose from the power
steering Pump. Allow the remaining power steering
fluid to drain from the power steering pump and res-
ervoir through the removed return hose.
Fig. 3 Catalytic Converter to Exhaust Manifold
1 - CATALYTIC CONVERTER
2 - BOLT
3 - GASKET
4 - FLAG NUT
Fig. 4 Exhaust System - Typical (All Vehicles)
1 - CATALYTIC CONVERTER 4 - SUPPORT - RESONATOR
2 - BAND CLAMP 5 - RESONATOR
3 - SUPPORTS - MUFFLER 6 - MUFFLER
19 - 38 PUMPRS
PUMP (Continued)
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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)
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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)
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BUCKET SEAT BACK - QUAD BUCKET -
INSTALLATION.......................23-97
BUCKET SEAT BACK - QUAD BUCKET -
REMOVAL..........................23-97
BUCKET SEAT RISER - INSTALLATION,
QUAD..............................23-96
BUCKET SEAT RISER - REMOVAL, QUAD . . 23-96
BUCKET SEAT SIDE SHIELD - NO CUP
HOLDER - INSTALLATION, QUAD........23-96
BUCKET SEAT SIDE SHIELD - NO CUP
HOLDER - REMOVAL, QUAD............23-96
BUCKET SEAT SIDE SHIELD/CUP
HOLDER - INSTALLATION, QUAD........23-95
BUCKET SEAT SIDE SHIELD/CUP
HOLDER - REMOVAL, QUAD............23-95
BUCKLE - FIRST ROW - BENCH -
INSTALLATION, SEAT BELT.............8O-12
BUCKLE - FIRST ROW - BENCH -
REMOVAL, SEAT BELT................8O-12
BUCKLE - FIRST ROW INBOARD - QUAD
BUCKET - INSTALLATION, SEAT BELT....8O-11
BUCKLE - FIRST ROW INBOARD - QUAD
BUCKET - REMOVAL, SEAT BELT........8O-11
BUCKLE - FRONT INBOARD -
INSTALLATION, SEAT BELT.............8O-11
BUCKLE - FRONT INBOARD - REMOVAL,
SEAT BELT .........................8O-11
BUCKLE - SECOND ROW - THREE
PASSENGER BENCH - INSTALLATION,
SEAT BELT .........................8O-14
BUCKLE - SECOND ROW - THREE
PASSENGER BENCH - REMOVAL, SEAT
BELT ..............................8O-14
BUCKLE - SECOND ROW INBOARD -
50/50 BENCH - INSTALLATION, SEAT
BELT ..............................8O-12
BUCKLE - SECOND ROW INBOARD -
50/50 BENCH - REMOVAL, SEAT BELT....8O-12
BUMPER - DESCRIPTION, JOUNCE........2-35
BUMPER - INSTALLATION, STOP........23-25
BUMPER - OPERATION, JOUNCE.........2-35
BUMPER - REMOVAL, STOP............23-25
BUMPER BEZEL - INSTALLATION,
SLIDING DOOR STOP.................23-25
BUMPER BEZEL - REMOVAL, SLIDING
DOOR STOP........................23-25
BUMPER REINFORCEMENT -
INSTALLATION, FRONT.................13-2
BUMPER REINFORCEMENT -
INSTALLATION, REAR..................13-3
BUMPER REINFORCEMENT - REMOVAL,
FRONT..............................13-2
BUMPER REINFORCEMENT - REMOVAL,
REAR...............................13-3
BUS COMMUNICATION RECEIVE - PCM
INPUT - OPERATION, DATA.............8E-15
BUS, OPERATION - PROGRAMMABLE
COMMUNICATIONS INTERFACE (PCI).....14-21
BUSHING - INSTALLATION, LEAF SPRING
FRONT..............................2-29
BUSHING - REMOVAL, LEAF SPRING
FRONT..............................2-28
BUSHINGS - INSTALLATION, FRONT
CROSSMEMBER MOUNT...............13-12
BUSHINGS - REMOVAL, FRONT
CROSSMEMBER MOUNT...............13-12
BUSHINGS (DISC/DISC BRAKES) -
ASSEMBLY, CALIPER GUIDE PIN.........5-25
BUSHINGS (DISC/DISC BRAKES) -
DISASSEMBLY, CALIPER GUIDE PIN.......5-24
CABLE - CROSSOVER - INSTALLATION,
GEARSHIFT.........................21-76
CABLE - CROSSOVER - REMOVAL,
GEARSHIFT.........................21-73
CABLE - DESCRIPTION.................8P-4
CABLE - DESCRIPTION, ANTENNA BODY . . . 8A-4
CABLE - DESCRIPTION, SPARK PLUG.....8I-10
CABLE - DIAGNOSIS AND TESTING,
ANTENNA BODY......................8A-4
CABLE - DIAGNOSIS AND TESTING,
BATTERY...........................8F-16
CABLE - INSTALLATION................8P-4
CABLE - INSTALLATION, ANTENNA BODY
. . 8A-6
CABLE - INSTALLATION, FRONT
..........5-64
CABLE - INSTALLATION, GEAR SHIFT
....21-205
CABLE - INSTALLATION, HOLD OPEN
LATCH
.............................23-38
CABLE - INSTALLATION, INSIDE HANDLE
. . 23-37CABLE - INSTALLATION, INSTRUMENT
PANEL ANTENNA......................8A-9
CABLE - INSTALLATION, LATCH RELEASE . 23-61
CABLE - INSTALLATION, OUTSIDE
HANDLE............................23-36
CABLE - INSTALLATION, PARKING
BRAKE LEVER AND FRONT..............5-66
CABLE - INSTALLATION, THROTTLE
CONTROL..........................14-35
CABLE - OPERATION...................8P-4
CABLE - OPERATION, ANTENNA BODY.....8A-4
CABLE - REMOVAL....................8P-4
CABLE - REMOVAL, ANTENNA BODY......8A-5
CABLE - REMOVAL, FRONT..............5-64
CABLE - REMOVAL, GEAR SHIFT.......21-204
CABLE - REMOVAL, HOLD OPEN LATCH . . . 23-37
CABLE - REMOVAL, INSIDE HANDLE.....23-37
CABLE - REMOVAL, INSTRUMENT PANEL
ANTENNA...........................8A-8
CABLE - REMOVAL, LATCH RELEASE.....23-60
CABLE - REMOVAL, OUTSIDE HANDLE....23-36
CABLE - REMOVAL, PARKING BRAKE
LEVER AND FRONT....................5-65
CABLE - REMOVAL, THROTTLE
CONTROL..........................14-35
CABLE - SELECTOR - INSTALLATION,
GEARSHIFT.........................21-84
CABLE - SELECTOR - REMOVAL,
GEARSHIFT.........................21-81
CABLE ADJUSTMENT, ADJUSTMENTS -
GEARSHIFT........................21-206
CABLE ADJUSTMENT, INSTALLATION -
SYNCHRONIZING...............23-101,23-87
CABLE (FRONT) - INSTALLATION,
PARKING BRAKE......................5-63
CABLE (FRONT) - REMOVAL, PARKING
BRAKE..............................5-59
CABLE (INTERMEDIATE) -
INSTALLATION, PARKING BRAKE.........5-63
CABLE (INTERMEDIATE) - REMOVAL,
PARKING BRAKE......................5-60
CABLE (LEFT REAR) - INSTALLATION,
PARKING BRAKE......................5-64
CABLE (LEFT REAR) - REMOVAL,
PARKING BRAKE......................5-62
CABLE RESISTANCE, SPECIFICATIONS -
SPARK PLUG.........................8I-2
CABLE (RIGHT REAR) - INSTALLATION,
PARKING BRAKE......................5-63
CABLE (RIGHT REAR) - REMOVAL,
PARKING BRAKE......................5-60
CABLES - ADJUSTMENT, PARKING
BRAKE..............................5-64
CABLES - DESCRIPTION, BATTERY.......8F-16
CABLES - INSTALLATION, BATTERY......8F-18
CABLES - OPERATION, BATTERY........8F-16
CABLES - REMOVAL, BATTERY..........8F-18
CALIBRATION - STANDARD PROCEDURE,
COMPASS...........................8M-3
CALIBRATION - STANDARD PROCEDURE,
HEATER-A/C CONTROL.................24-8
CALIPER - CLEANING..............5-25,5-29
CALIPER - INSPECTION............5-25,5-29
CALIPER - INSTALLATION, REAR DISC
BRAKE..............................5-30
CALIPER - REMOVAL, REAR DISC
BRAKE..............................5-27
CALIPER ADAPTER - INSTALLATION,
FRONT DISC BRAKE...................5-31
CALIPER ADAPTER - REMOVAL, FRONT
DISC BRAKE.........................5-31
CALIPER (DISC/DISC BRAKES) -
INSTALLATION, FRONT DISC BRAKE......5-27
CALIPER (DISC/DISC BRAKES) -
REMOVAL, FRONT DISC BRAKE..........5-24
CALIPER (DISC/DRUM BRAKES) -
INSTALLATION, FRONT DISC BRAKE......5-27
CALIPER (DISC/DRUM BRAKES) -
REMOVAL, FRONT DISC BRAKE
..........5-24
CALIPER GUIDE PIN BUSHINGS
(DISC/DISC BRAKES) - ASSEMBLY
........5-25
CALIPER GUIDE PIN BUSHINGS
(DISC/DISC BRAKES) - DISASSEMBLY
.....5-24
CALIPER GUIDE PINS (DISC/DRUM
BRAKES) - INSTALLATION, DISC
BRAKE
..............................5-31
CALIPER GUIDE PINS (DISC/DRUM
BRAKES) - REMOVAL, DISC BRAKE
.......5-31CALIPER PISTON AND SEAL -
ASSEMBLY......................5-26,5-29
CALIPER PISTON AND SEAL -
DISASSEMBLY....................5-24,5-28
CAMSHAFT & BEARINGS (IN BLOCK) -
DESCRIPTION.......................9-115
CAMSHAFT & BEARINGS (IN BLOCK) -
INSPECTION........................9-115
CAMSHAFT & BEARINGS (IN BLOCK) -
INSTALLATION.......................9-115
CAMSHAFT & BEARINGS (IN BLOCK) -
OPERATION.........................9-115
CAMSHAFT & BEARINGS (IN BLOCK) -
REMOVAL..........................9-115
CAMSHAFT END PLAY - STANDARD
PROCEDURE, MEASURING..............9-29
CAMSHAFT OIL SEAL(S) - INSTALLATION . . 9-28
CAMSHAFT OIL SEAL(S) - REMOVAL......9-27
CAMSHAFT POSITION SENSOR -
DESCRIPTION.........................8I-3
CAMSHAFT POSITION SENSOR -
OPERATION..........................8I-3
CAMSHAFT SPROCKET - INSTALLATION,
TIMING CHAIN.......................9-157
CAMSHAFT SPROCKET - REMOVAL,
TIMING CHAIN.......................9-156
CAMSHAFT SPROCKETS - INSTALLATION . . 9-65
CAMSHAFT SPROCKETS - REMOVAL......9-64
CAMSHAFT(S) - CLEANING..............9-29
CAMSHAFT(S) - DESCRIPTION...........9-28
CAMSHAFT(S) - INSPECTION............9-30
CAMSHAFT(S) - INSTALLATION..........9-30
CAMSHAFT(S) - OPERATION.............9-28
CAMSHAFT(S) - REMOVAL..............9-29
CANISTER - DESCRIPTION, VAPOR......25-18
CANISTER - INSTALLATION, REAR EVAP . . 25-20
CANISTER - OPERATION, VAPOR........25-18
CANISTER - REMOVAL, REAR EVAP......25-19
CAP - DESCRIPTION, FUEL FILLER.......25-12
CAP - DESCRIPTION, RADIATOR
PRESSURE..........................7-26
CAP - INSTALLATION, INSTRUMENT
PANEL END.........................23-67
CAP - OPERATION, FUEL FILLER........25-12
CAP - OPERATION, RADIATOR
PRESSURE..........................7-27
CAP - REMOVAL, INSTRUMENT PANEL
END ...............................23-67
CAP TESTING - DIAGNOSIS AND
TESTING, COOLING SYSTEM
PRESSURE..........................7-27
CAP TO FILLER NECK SEAL -
DIAGNOSIS AND TESTING, RADIATOR.....7-27
CAPACITIES - SPECIFICATIONS, FLUID......0-6
CARE - CLEANING, ALUMINUM WHEEL . . . 22-18
CARPETS AND FLOOR MATS -
INSTALLATION.......................23-75
CARPETS AND FLOOR MATS - REMOVAL . 23-74
CARRIER ASSEMBLY - DESCRIPTION,
BALANCE SHAFTS.....................9-69
CARRIER ASSEMBLY - INSTALLATION,
BALANCE SHAFTS.....................9-72
CARRIER ASSEMBLY - OPERATION,
BALANCE SHAFTS.....................9-69
CARRIER ASSEMBLY - REMOVAL,
BALANCE SHAFTS.....................9-69
CARRIER SEAL - INSTALLATION,
DIFFERENTIAL........................21-9
CARRIER SEAL - REMOVAL,
DIFFERENTIAL........................21-9
CATALYTIC CONVERTER - DESCRIPTION . . . 11-4
CATALYTIC CONVERTER - INSPECTION....11-5
CATALYTIC CONVERTER - INSTALLATION . . . 11-6
CATALYTIC CONVERTER - OPERATION.....11-4
CATALYTIC CONVERTER - REMOVAL......11-5
CAUSES - DIAGNOSIS AND TESTING,
COMMON PROBLEM..................21-30
CAUTION - CAUTIONS..................5-78
CAUTION, A/C PLUMBING..............24-61
CAUTION, DESCRIPTION.................5-4
CAUTION, DESCRIPTION...............19-37
CAUTION, SENSOR - TPM..............22-10
CAUTIONS, CAUTION..................5-78
CAUTIONS, WARNING - WARNINGS
. 19-10,19-27
CD CHANGER - DESCRIPTION
...........8A-7
CD CHANGER - INSTALLATION
...........8A-8
CD CHANGER - OPERATION
.............8A-7
CD CHANGER - REMOVAL
..............8A-8
RSINDEX5
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