2004 CHRYSLER VOYAGER relay

(1) Disconnect and isolate the battery negative
cable.
(2) Disconnect the rear HVAC wire harness con-
nector from the rear blower motor resistor.
(3) Check for continuity between each of the
blower motor switch input terminals of the blower
motor resistor and the resistor output terminal. In
each case there should be continuity. If OK, repair
the wire harness circuits between the blower motor
switch and the blower motor resistor, blower motor or
blower motor relay as required. If not OK, replace
the faulty blower motor resistor block.
REMOVAL
WARNING: THE REAR BLOWER MOTOR RESISTOR
BLOCK MAY GET VERY HOT DURING NORMAL
OPERATION. IF THE BLOWER MOTOR WAS
TURNED ON PRIOR TO SERVICING THE BLOWER
MOTOR RESISTOR BLOCK, WAIT FIVE MINUTES
TO ALLOW THE BLOWER MOTOR RESISTORS TO
COOL BEFORE PERFORMING DIAGNOSIS OR SER-
VICE. FAILURE TO TAKE THIS PRECAUTION CAN
RESULT IN PERSONAL INJURY.
CAUTION: Do not operate the blower motor with the
blower motor resistor block removed from the cir-
cuit. Failure to take this precaution can result in
vehicle damage.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the right quarter trim panel and right
D-pillar trim panel from the quarter inner panel
(Refer to 23 - BODY/INTERIOR/QUARTER TRIM
PANEL - REMOVAL).
(3) Disconnect the rear HVAC wire harness con-
nector from the blower motor resistor block (Fig. 6).
(4) Remove the two screws that secure the blower
motor resistor block to the rear HVAC housing.
(5) Remove the rear blower motor resistor block
from the rear HVAC housing.
INSTALLATION
(1) Position the rear blower motor resistor block
into the rear HVAC housing.
(2) Install the two screws that secure the rear
blower motor resistor block to the rear HVAC hous-
ing. Tighten the screws to 2 N´m (17 in. lbs.).
(3) Connect the rear HVAC wire harness connector
to the rear blower motor resistor block.
(4) Reinstall the right quarter trim panel and
right D-pillar trim panel onto the quarter inner
panel (Refer to 23 - BODY/INTERIOR/QUARTER
TRIM PANEL - INSTALLATION).
(5) Reconnect the battery negative cable.
MODE DOOR ACTUATOR -
REAR
DESCRIPTION
The rear mode door actuator is a reversible, 12-volt
Direct Current (DC), servo motor. The mode door actua-
tor is located on the outboard side of the rear HVAC
housing, above the blend door actuator. The mode door
actuator is mechanically connected to the mode door.
The rear mode door actuator is interchangeable with
the actuator for the blend door. Each actuator is con-
tained within an identical black molded plastic housing
with an integral wire connector receptacle. Two integral
mounting tabs allow the actuator to be secured with
two screws to the rear HVAC housing. Each actuator
also has an identical output shaft with splines that con-
nects it to the pivot or linkage of the proper door. The
rear mode door actuator does not require mechanical
indexing to the mode door pivot, as it is electronically
calibrated by the front heater-A/C control module.
Fig. 6 Rear Blower Motor Resistor Block
1 - REAR HVAC HOUSING
2 - D-PILLAR
3 - BLOWER PIGTAIL WIRE
4 - CONNECTOR
5 - EXPANSION VALVE
6 - SCREW (2)
7 - BLOWER MOTOR RESISTOR BLOCK
RSCONTROLS - REAR24-39
BLOWER MOTOR RESISTOR (Continued)

(6) Install the screw that secures the front of the
rear HVAC housing to the right quarter inner panel.
Tighten the screw to 11 N´m (97 in. lbs.).
(7) Install the screw that secures the back of the
rear HVAC housing to the right D-pillar. Tighten the
screw to 11 N´m (97 in. lbs.).
(8) Install the two screws that secure the top of
the quarter trim panel attaching bracket to the quar-
ter inner panel. Tighten the screws to 2 N´m (17 in.
lbs.).
(9) Reinstall the right quarter trim panel and
right D-pillar trim panel onto the quarter inner
panel (Refer to 23 - BODY/INTERIOR/QUARTER
TRIM PANEL - INSTALLATION).
(10) Reconnect the battery negative cable.
(11) Perform the heater-A/C control calibration
procedure (Refer to 24 - HEATING & AIR CONDI-
TIONING/CONTROLS - FRONT/A/C-HEATER CON-
TROL - STANDARD PROCEDURE - HEATER-A/C
CONTROL CALIBRATION).
POWER MODULE - REAR
BLOWER MOTOR
DESCRIPTION
A rear blower motor power module is used on this
model when it is equipped with the optional Auto-
matic Temperature Control (ATC) system. Models
equipped with the standard manual heater-A/C sys-
tem use a blower motor resistor block , instead of the
blower motor power module (Refer to 24 - HEATING
& AIR CONDITIONING/CONTROLS/BLOWER
MOTOR RESISTOR BLOCK - DESCRIPTION).
The rear blower motor power module is installed in
the back of the rear HVAC housing, directly above
the expansion valve. The module consists of a molded
plastic mounting plate with two integral connector
receptacles. Concealed behind the mounting plate
within the evaporator housing is the power module
electronic circuitry and a large finned, heat sink. The
power module is accessed for service by removing the
right quarter and D-pillar trim panels.
OPERATION
The rear blower motor power module is connected
to the vehicle electrical system through a dedicated
take out and connector of the rear HVAC wire har-
ness. A second connector receptacle receives the pig-
tail wire connector from the rear blower motor. The
rear blower motor power module allows the micropro-
cessor-based Automatic Temperature Control (ATC)
heater-A/C control module to calculate and provide
infinitely variable blower motor speeds based upon
either manual blower switch input or the ATC pro-
gramming using a Pulse Width Modulated (PWM)circuit strategy. The PWM voltage is applied to a
comparator circuit which compares the PWM signal
voltage to the blower motor feedback voltage. The
resulting output drives the power module circuitry,
which adjusts the voltage output received from the
rear blower motor relay to change or maintain the
desired blower speed. The rear blower motor power
module is diagnosed using a DRBIIItscan tool. Refer
to Body Diagnostic Procedures.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the right quarter trim panel and right
D-pillar trim panel from the quarter inner panel
(Refer to 23 - BODY/INTERIOR/QUARTER TRIM
PANEL - REMOVAL).
(3) Disconnect the rear HVAC wire harness con-
nector from the rear blower motor power module
(Fig. 8).
(4) Disconnect the rear blower motor pigtail wire
connector from the rear blower motor power module.
(5) Remove the two screws that secure the rear
blower motor power module to the rear HVAC hous-
ing.
(6) Remove the rear blower motor power module
from the rear HVAC housing.
Fig. 8 Rear Blower Motor Power Module
1 - REAR HVAC HOUSING
2 - SCREW (2)
3 - D-PILLAR
4 - REAR BLOWER MOTOR PIGTAIL WIRE
5 - REAR HVAC WIRE HARNESS
6 - EXPANSION VALVE
7 - REAR BLOWER MOTOR POWER MODULE
RSCONTROLS - REAR24-41
MODE DOOR ACTUATOR - REAR (Continued)

(2) Engage the retainer features on the top of the
outlet housing with their receptacles at the top of the
center bezel, then roll the bottom of the outlet hous-
ing downwards towards the center bezel.
(3) Install the three screws that secure the bottom
of the outlet housing to the center bezel. Tighten the
screws to 2 N´m (17 in. lbs.).
(4) If the vehicle is equipped with the optional
ATC system, reconnect the ATC remote infrared tem-
perature sensor jumper harness to the sensor connec-
tor receptacle located on the bottom of the center
outlet housing.
(5) Reinstall the center bezel onto the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - INSTAL-
LATION).
(6) Reconnect the battery negative cable.
INSTALLATION - DEMISTER OUTLET
(1) Position the demister outlet over the demister
duct opening in the instrument panel top pad.
(2) Using hand pressure, press the demister outlet
firmly and evenly into the instrument panel top pad
opening until the snap features on the outlet are
fully engaged.
INSTALLATION - INSTRUMENT PANEL OUTLET
(1) Position the instrument panel outlet into the
panel duct opening in the instrument panel top pad.
(2) Using hand pressure, press the instrument
panel outlet firmly and evenly into the instrument
panel top pad opening until the snap features on the
outlet are fully engaged.
BLOWER MOTOR
DESCRIPTION
The blower motor is a 12-volt, Direct Current (DC)
motor with a squirrel cage-type blower wheel that is
secured to the blower motor shaft (Fig. 6). The
blower motor and wheel are located near the passen-
ger side end of the HVAC housing in the passenger
compartment below the instrument panel. The
blower motor and blower motor wheel are factory bal-
anced and cannot be adjusted or repaired. If faulty or
damaged, the blower motor and blower wheel must
be replaced as an assembly.
OPERATION
On models equipped with the manual heater-A/C
system, the blower motor will operate whenever the
ignition switch is in the On position and the blower
control switch is in any position except Off. On mod-
els equipped with the Automatic Temperature Con-
trol (ATC) system, the blower motor will operate
whenever the ignition switch is in the On position
and the A/C-heater control power is turned on.
The blower motor receives battery current when-
ever the front blower motor relay is energized. The
front blower motor relay output circuit is protected
by a fuse in the Integrated Power Module (IPM)
located in the engine compartment near the battery.
In the manual heater-A/C system, the blower motor
speed is controlled by regulating the path to ground
through the blower control switch and the blower
motor resistor. In the ATC system, the blower motor
speed is controlled by an electronic blower motor
power module, which uses a pulse width modulated
input from the ATC module and feedback from the
Fig. 5 Instrument Panel Outlet - Left Side Shown
1 - INSTRUMENT PANEL TOP PAD
2 - INSTRUMENT PANEL OUTLET
3 - TRIM STICK
Fig. 6 Blower Motor
1 - BLOWER MOTOR
2 - RUBBER GROMMET
3 - BLOWER MOTOR CONNECTOR
4 - MOUNTING TABS
24 - 46 DISTRIBUTION - FRONTRS
AIR OUTLETS (Continued)

blower motor to regulate the blower motor ground
path it provides. The blower motor and wheel are
used to control the velocity of air moving through the
HVAC housing by spinning the blower wheel within
the housing at the selected speed or, in the ATC sys-
tem, at the selected or programmed speed.
DIAGNOSIS AND TESTING - BLOWER MOTOR
BLOWER MOTOR INOPERATIVE
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 ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
For circuit descriptions and diagrams, refer to the
appropriate wiring information. The wiring informa-
tion includes wiring, diagrams, proper wire and con-
nector repair procedures, further details on wire
harness routing and retention, as well as pin-out and
location views for the various wire harness connec-
tors, splices and grounds.
BLOWER MOTOR ELECTRICAL DIAGNOSIS
(1) Check the fuse (Fuse 10 - 40 ampere) in the
Integrated Power Module (IPM). 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 On position. Be
certain that the A/C-heater control power is turned
on. Check for battery voltage at the fuse (Fuse 10 -
40 ampere) in the IPM. If OK, go to Step 3. If not
OK, check the front blower motor relay.
(3) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the front HVAC wire harness connector
for the front blower motor resistor block (Manual
Temperature Control) or the front blower motor
power module (Automatic Temperature Control) from
the resistor or module connector receptacle. Recon-
nect the battery negative cable. Turn the ignition
switch to the On position. Be certain that the A/C-
heater control power is turned on. Check for battery
voltage at the fused front blower motor relay output
circuit cavity of the front HVAC wire harness connec-
tor for the front blower motor resistor block (MTC) orthe front blower motor power module (ATC). If OK,
go to Step 4. If not OK, repair the open fused front
blower motor relay output circuit to the IPM as
required.
(4) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the front blower motor pigtail wire con-
nector from the connector receptacle of the front
blower motor resistor block (MTC) or the front
blower motor power module (ATC). Use jumper wires
to connect a battery and ground feeds to the blower
motor pigtail wire connector. The blower motor
should operate. If OK with MTC, proceed to diagno-
sis of the front blower motor resistor block (Refer to
24 - HEATING & AIR CONDITIONING/CONTROLS
- FRONT/BLOWER MOTOR RESISTOR - DIAGNO-
SIS AND TESTING). If OK with ATC, use a DRBIII
scan tool to diagnose the front blower motor power
module. Refer to Body Diagnostic information. If not
OK with MTC or ATC, replace the faulty front blower
motor.
BLOWER MOTOR NOISE OR VIBRATION
Refer to the Blower Motor Noise/Vibration Diagno-
sis chart for basic checks of the blower motor when a
vibration or noise is present (Fig. 7).
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 ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
NOTE: The blower motor is located on the passen-
ger side of the vehicle under the instrument panel.
The blower motor can be removed from the vehicle
without having to remove the HVAC housing.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the passenger side door sill plate and
cowl panel.
(3) Pull back the carpet to access the front lower
air intake screw.
RSDISTRIBUTION - FRONT24-47
BLOWER MOTOR (Continued)

DISTRIBUTION DUCT
REMOVAL
(1) Remove the trim from the right quarter inner
panel and the right D pillaR (Refer to 23 - BODY/IN-
TERIOR/RIGHT QUARTER TRIM PANEL -
REMOVAL).
(2) Slide the rear distribution duct upwards far
enough to disengage it from the outlet at the top of
the rear HVAC housing (Fig. 2).
(3) While pulling the lower end of the rear distri-
bution duct away from the rear HVAC housing out-
let, disengage the upper end of the distribution duct
from the headliner duct.
(4) Remove the rea distribution duct from the
vehicle.
INSTALLATION
(1) Align the upper end of the rear distribution
duct to the headliner duct.
(2) Slide the upper end of the rear distribution
duct onto the headliner duct far enough to align the
lower end of the duct with the outlet at the top of the
rear HVAC housing.
(3) Slide the rear distribution duct downwards far
enough to engage it onto the outlet at the top of the
rear HVAC housing.
(4) Reinstall the trim onto the right quarter inner
panel and the right D pillar (Refer to 23 - BODY/IN-
TERIOR/RIGHT QUARTER TRIM PANEL -
INSTALLATION).
BLOWER MOTOR
DESCRIPTION
The blower motor is a 12-volt, Direct Current (DC)
motor with a squirrel cage-type blower wheel that is
secured to the blower motor shaft. The blower motor
and wheel are located near the top of the rear HVAC
housing in the passenger compartment behind the
right rear wheel house. The rear HVAC housing must
be removed from the vehicle to access the blower
motor for service. The blower motor and blower
motor wheel are a factory balanced unit and cannot
be adjusted or repaired. If faulty or damaged, the
blower motor and blower wheel must be replaced as
a unit.
OPERATION
On models equipped with the Manual Temperature
Control (MTC) system, the rear blower motor will
operate only whenever the ignition switch is in the
On position, the front blower control switch is in any
position except Off and the rear blower control switch
on the front A/C-heater control is in any position
except Off. On models equipped with the Automatic
Temperature Control (ATC) system, the blower motor
will operate whenever the ignition switch is in the
On position, the A/C-heater control power is turned
on and the rear blower control switch on the front
A/C-heater control is in any position except Off. The
rear blower motor can only be turned off by turning
off the rear system at the front A/C-heater control.
The rear blower motor receives battery current
whenever the rear blower motor relay is energized.
The rear blower motor relay output circuit is pro-
tected by a fuse in the Integrated Power Module
(IPM) located in the engine compartment near the
battery. In the MTC system, the rear blower motor
speed is controlled by regulating the path to ground
through the blower control switch and the blower
motor resistor. In the ATC system, the rear blower
motor speed is controlled by an electronic blower
motor power module, which uses a pulse width mod-
ulated input from the ATC control module and feed-
back from the rear blower motor to regulate the
blower motor ground path it provides. The rear
blower motor and wheel are used to control the veloc-
ity of air moving through the rear HVAC housing.
The rear blower motor controls the velocity of the air
flowing through the rear HVAC housing by spinning
the blower wheel within the housing at the selected
speed or, in the ATC system, at the selected or pro-
grammed speed.
Fig. 2 Rear Distribution Duct
1 - HEADLINER DUCT
2 - REAR DISTRIBUTION DUCT
3 - REAR HVAC HOUSING OUTLET
RSDISTRIBUTION - REAR24-57

DIAGNOSIS AND TESTING - REAR BLOWER
MOTOR
BLOWER MOTOR INOPERATIVE
For circuit descriptions and diagrams, refer to the
appropriate wiring information. The wiring informa-
tion includes wiring, diagrams, proper wire and con-
nector repair procedures, further details on wire
harness routing and retention, as well as pin-out and
location views for the various wire harness connec-
tors, splices and grounds.
BLOWER MOTOR ELECTRICAL DIAGNOSIS
(1) Check the fuse (Fuse 12 - 25 ampere) in the
Integrated Power Module (IPM). 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 On position. Be
certain that the rear A/C-heater control power is
turned on. Check for battery voltage at the fuse
(Fuse 12 - 25 ampere) in the IPM. If OK, go to Step
3. If not OK, check the rear blower motor relay.
(3) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the rear HVAC wire harness connector
from the rear blower motor resistor block (Manual
Temperature Control) or the rear blower motor power
module (Automatic Temperature Control). Reconnect
the battery negative cable. Turn the ignition switch
to the On position. Be certain that the rear A/C-
heater control power is turned on. Check for battery
voltage at the fused rear blower motor relay output
circuit cavity of the rear HVAC wire harness connec-
tor for the rear blower motor resistor block (MTC) or
the rear blower motor power module (ATC). If OK, go
to Step 4. If not OK, repair the open fused front
blower motor relay output circuit to the IPM as
required.
(4) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the rear blower motor pigtail wire connec-
tor from the rear HVAC wire harness (MTC) or the
rear blower power module (ATC). Use jumper wires
to connect a battery and ground feeds to the blower
motor pigtail wire connector. The rear blower motor
should operate. If OK with MTC, proceed to diagno-
sis of the rear blower motor resistor block (Refer to
24 - HEATING & AIR CONDITIONING/CONTROLS
- REAR/BLOWER MOTOR RESISTOR - DIAGNOSIS
AND TESTING). If OK with ATC, use a DRBIII scan
tool to diagnose the rear blower motor power module.
Refer to the appropriate diagnostic information. If
not OK with MTC or ATC, replace the faulty rear
blower motor.BLOWER MOTOR NOISE OR VIBRATION
Refer to the Blower Motor Noise/Vibration Diagno-
sis chart for basic checks of the blower motor when a
vibration or noise is present (Fig. 3).
REMOVAL
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
WARNING) and (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING - CAUTION).
(1) Remove the rear HVAC housing from the vehi-
cle (Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL).
(2) Disconnect the rear blower motor pigtail wire
connector.
NOTE: With the Manual Temperature Control sys-
tem, the blower motor pigtail wire is connected to a
take out and connector of the rear HVAC wire har-
ness. With the Automatic Temperature Control sys-
tem , the blower pigtail wire is connected to a
receptacle on the blower motor power module.
(3) Remove the three screws that secure the rear
blower motor to the outboard side of the rear HVAC
housing (Fig. 4).
(4) Remove the rear blower motor from the rear
HVAC housing.
INSTALLATION
(1) Position the rear blower motor into the rear
HVAC housing.
(2) Install the three screws that secure the blower
motor to the rear HVAC housing. Tighten the screws
to 2 N´m (17 in. lbs.).
(3) Reconnect the rear blower motor pigtail wire
connector.
NOTE: With the Manual Temperature Control system
, the blower pigtail wire is connected to a take out
and connector of the rear HVAC wire harness. With
the Automatic Temperature Control system, the
blower pigtail wire is connected to a receptacle on
the blower motor power module.
24 - 58 DISTRIBUTION - REARRS
BLOWER MOTOR (Continued)

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)

INDEX
ABS FASTENER TORQUE,
SPECIFICATIONS......................5-79
ABSORBER - DESCRIPTION, SHOCK.......2-37
ABSORBER - INSTALLATION, SHOCK......2-38
ABSORBER - OPERATION, SHOCK........2-37
ABSORBER - REMOVAL, SHOCK..........2-37
ABSORBER (UPPER BUSHING) -
ASSEMBLY, SHOCK....................2-38
ABSORBER (UPPER BUSHING) -
DISASSEMBLY, SHOCK.................2-37
A/C COMPRESSOR - DESCRIPTION......24-73
A/C COMPRESSOR - OPERATION........24-73
A/C COMPRESSOR CLUTCH COIL -
DIAGNOSIS AND TESTING.............24-15
A/C COMPRESSOR CLUTCH RELAY -
DESCRIPTION.......................24-19
A/C COMPRESSOR CLUTCH RELAY -
INSTALLATION.......................24-20
A/C COMPRESSOR CLUTCH RELAY -
OPERATION.........................24-19
A/C COMPRESSOR CLUTCH RELAY -
REMOVAL..........................24-20
A/C COMPRESSOR CLUTCH/COIL -
DESCRIPTION.......................24-15
A/C COMPRESSOR CLUTCH/COIL -
INSPECTION........................24-17
A/C COMPRESSOR CLUTCH/COIL -
INSTALLATION.......................24-17
A/C COMPRESSOR CLUTCH/COIL -
OPERATION.........................24-15
A/C COMPRESSOR CLUTCH/COIL -
REMOVAL..........................24-16
A/C COMPRESSOR MOUNTING BRACKET
- 2.4L ENGINE - INSTALLATION.........24-76
A/C COMPRESSOR MOUNTING BRACKET
- 2.4L ENGINE - REMOVAL.............24-75
A/C CONDENSER - DESCRIPTION........24-76
A/C CONDENSER - INSTALLATION.......24-78
A/C CONDENSER - OPERATION..........24-76
A/C CONDENSER - REMOVAL...........24-77
A/C COOL DOWN TEST - DIAGNOSIS
AND TESTING........................24-6
A/C DISCHARGE LINE - INSTALLATION . . . 24-80
A/C DISCHARGE LINE - REMOVAL.......24-79
A/C EVAPORATOR - DESCRIPTION . . 24-80,24-97
A/C EVAPORATOR - INSTALLATION......24-80
A/C EVAPORATOR - INSTALLATION,
REAR..............................24-99
A/C EVAPORATOR - OPERATION....24-80,24-97
A/C EVAPORATOR - REMOVAL..........24-80
A/C EVAPORATOR - REMOVAL, REAR.....24-97
A/C EVAPORATOR LINE EXTENSION -
INSTALLATION, REAR.................24-99
A/C EVAPORATOR LINE EXTENSION -
REMOVAL..........................24-98
A/C EXPANSION VALVE - DESCRIPTION . . . 24-99
A/C EXPANSION VALVE - DIAGNOSIS
AND TESTING.......................24-81
A/C EXPANSION VALVE - INSTALLATION . 24-100
A/C EXPANSION VALVE - OPERATION.....24-99
A/C EXPANSION VALVE - REMOVAL.....24-100
A/C HEATER CONTROL - DESCRIPTION . . . 24-20
A/C HEATER CONTROL - INSTALLATION . . . 24-21
A/C HEATER CONTROL - REMOVAL......24-21
A/C PERFORMANCE TEST - DIAGNOSIS
AND TESTING........................24-7
A/C PRESSURE TRANSDUCER -
DESCRIPTION.......................24-21
A/C PRESSURE TRANSDUCER -
DIAGNOSIS AND TESTING.............24-22
A/C PRESSURE TRANSDUCER -
INSTALLATION.......................24-22
A/C PRESSURE TRANSDUCER -
OPERATION.........................24-21
A/C PRESSURE TRANSDUCER -
REMOVAL..........................24-22
A/C SYSTEM, CAUTION................24-66
A/C SYSTEM, SPECIFICATIONS..........24-11
A/C SYSTEM, WARNING...............24-65
ACCELERATOR PEDAL - INSTALLATION . . . 14-24
ACCELERATOR PEDAL - REMOVAL
.......14-24
ACCESSORY DRIVE BELT - DIAGNOSIS
AND TESTING
.........................7-7
ACCESSORY DRIVE BELT TENSION,
SPECIFICATIONS
.......................7-5
ACCUMULATOR - DESCRIPTION
.......21-188,
21s-206,21s-94
ACCUMULATOR - OPERATION
....21-189,21s-94A/C-HEATER CONTROL - DESCRIPTION . . . 24-34
A/C-HEATER CONTROL - INSTALLATION . . . 24-35
A/C-HEATER CONTROL - OPERATION.....24-34
A/C-HEATER CONTROL - REMOVAL......24-34
A/C-HEATER CONTROL CALIBRATION -
STANDARD PROCEDURE...............24-20
ACTUATOR - DESCRIPTION, BLEND
DOOR........................24-23,24-35
ACTUATOR - DESCRIPTION, ENGAGE.....8N-10
ACTUATOR - DESCRIPTION, LATCH......8N-14
ACTUATOR - DESCRIPTION, MODE
DOOR.............................24-30
ACTUATOR - DESCRIPTION,
RECIRCULATION DOOR................24-32
ACTUATOR - INSTALLATION, BLEND
DOOR........................24-23,24-36
ACTUATOR - INSTALLATION, ENGAGE....8N-11
ACTUATOR - INSTALLATION, INSIDE
HANDLE............................23-27
ACTUATOR - INSTALLATION, LATCH.....8N-14
ACTUATOR - INSTALLATION, MODE
DOOR.............................24-31
ACTUATOR - INSTALLATION,
RECIRCULATION DOOR................24-33
ACTUATOR - OPERATION, BLEND DOOR . . 24-23,
24-35
ACTUATOR - OPERATION, ENGAGE......8N-11
ACTUATOR - OPERATION, LATCH........8N-14
ACTUATOR - OPERATION, MODE DOOR . . . 24-30
ACTUATOR - OPERATION,
RECIRCULATION DOOR................24-32
ACTUATOR - REAR - DESCRIPTION,
MODE DOOR........................24-39
ACTUATOR - REAR - INSTALLATION,
MODE DOOR........................24-40
ACTUATOR - REAR - OPERATION, MODE
DOOR.............................24-40
ACTUATOR - REAR - REMOVAL, MODE
DOOR.............................24-40
ACTUATOR - REMOVAL, BLEND DOOR . . . 24-23,
24-36
ACTUATOR - REMOVAL, ENGAGE........8N-11
ACTUATOR - REMOVAL, INSIDE HANDLE . . 23-27
ACTUATOR - REMOVAL, LATCH.........8N-14
ACTUATOR - REMOVAL, MODE DOOR....24-30
ACTUATOR - REMOVAL, RECIRCULATION
DOOR.............................24-33
ADAPTER - INSTALLATION, FRONT DISC
BRAKE CALIPER.................5-31,5s-30
ADAPTER - INSTALLATION, OIL FILTER . . . 9-139
ADAPTER - REMOVAL, FRONT DISC
BRAKE CALIPER.................5-31,5s-30
ADAPTER - REMOVAL, OIL FILTER.......9-139
ADAPTIVE MEMORIES, OPERATION -
FUEL CORRECTION OR................14-20
ADDING ADDITIONAL COOLANT -
STANDARD PROCEDURE.................7-5
ADDITIONAL COOLANT - STANDARD
PROCEDURE, ADDING...................7-5
ADHESIVE ATTACHED - INSTALLATION,
EXTERIOR NAME PLATES..............23-51
ADHESIVE ATTACHED - REMOVAL,
EXTERIOR NAME PLATES..............23-51
ADHESIVE LOCATIONS -
SPECIFICATIONS, STRUCTURAL
........23-156
ADJUSTABLE - INSTALLATION, PEDALS
. . . 5s-40
ADJUSTABLE - REMOVAL, PEDALS
.......5s-38
ADJUSTABLE PEDALS SWITCH -
INSTALLATION
.......................5s-10
ADJUSTABLE PEDALS SWITCH -
REMOVAL
..........................5s-10
ADJUSTER-BORC-PILLAR -
INSTALLATION, SEAT BELT HEIGHT
......8O-13
ADJUSTER-BORC-PILLAR -
REMOVAL, SEAT BELT HEIGHT
..........8O-13
ADJUSTER - DIAGNOSIS AND TESTING,
DRUM BRAKE AUTOMATIC
.........5-13,5s-13
ADJUSTER - INSTALLATION, FRONT
SEAT TRACK MANUAL
................23-95
ADJUSTER - INSTALLATION, FRONT
SEAT TRACK POWER
.................23-95
ADJUSTER - REMOVAL, FRONT SEAT
TRACK MANUAL
.....................23-95
ADJUSTER - REMOVAL, FRONT SEAT
TRACK POWER
......................23-95
ADJUSTER KNOB - INSTALLATION, SEAT
BELT HEIGHT
.......................8O-14ADJUSTER KNOB - REMOVAL, SEAT
BELT HEIGHT.......................8O-14
ADJUSTER NOISE DIAGNOSIS -
DIAGNOSIS AND TESTING, HYDRAULIC
LASH...............................9-34
ADJUSTER TENSION RELEASE -
STANDARD PROCEDURE, PARKING
BRAKE AUTOMATIC...............5-58,5s-61
ADJUSTER TENSION RESET -
STANDARD PROCEDURE, PARKING
BRAKE AUTOMATIC...............5-59,5s-61
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 CONDITIONER - DESCRIPTION,
HEATER .............................24-1
AIR CONDITIONER - OPERATION,
HEATER .............................24-4
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..............23-57
AIR EXHAUSTER - INSTALLATION, REAR
QUARTER PANEL/FENDER..............23-58
AIR EXHAUSTER - REMOVAL, REAR
QUARTER PANEL/FENDER..............23-57
AIR FILTER - DESCRIPTION............24-43
AIR FILTER - INSTALLATION............24-44
AIR FILTER - REMOVAL...............24-43
AIR GAP, SPECIFICATIONS - WHEEL
SPEED SENSOR.......................5-79
AIR INTAKE PIPE - INSTALLATION......24-114
AIR INTAKE PIPE - REMOVAL..........24-113
AIR OUTLETS - DESCRIPTION.....24-44,24-56
AIR OUTLETS - INSTALLATION..........24-56
AIR OUTLETS - REMOVAL.............24-56
AIR PRESSURE TESTS - DIAGNOSIS
AND TESTING, CLUTCH.........21-122,21s-30
AIR TEMPERATURE SENSOR -
DESCRIPTION, INLET.................14-30
AIRBAG - DESCRIPTION, DRIVER........8O-6
AIRBAG - DESCRIPTION, PASSENGER.....8O-8
AIRBAG - DESCRIPTION, SEAT..........8O-11
AIRBAG - INSTALLATION, DRIVER........8O-7
AIRBAG - INSTALLATION, PASSENGER . . . 8O-10
AIRBAG - OPERATION, DRIVER..........8O-6
AIRBAG - OPERATION, PASSENGER.......8O-9
AIRBAG - OPERATION, SEAT...........8O-11
AIRBAG - REMOVAL, DRIVER
............8O-6
AIRBAG - REMOVAL, PASSENGER
........8O-9
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-7
AIRBAGS - STANDARD PROCEDURE,
HANDLING
..........................8O-3
AJAR SWITCH - EXPORT -
INSTALLATION, HOOD
.................8Q-3
AJAR SWITCH - EXPORT - REMOVAL,
HOOD
..............................8Q-3
ALIGNMENT - DESCRIPTION, WHEEL
......2-47
ALIGNMENT - EXPORT - STANDARD
PROCEDURE, FRONT FOG LAMP UNIT
.....8L-9
ALIGNMENT - EXPORT - STANDARD
PROCEDURE, HEADLAMP UNIT
.........8L-14
ALIGNMENT - STANDARD PROCEDURE,
FRONT FOG LAMP UNIT
................8L-9
RSINDEX1
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