2004 DODGE TOWN AND COUNTRY steering

INSTRUMENT PANEL
DEMISTER DUCTS
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 ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel from the vehicle.
(Refer to 23 - BODY/INSTRUMENT PANEL/IN-
STRUMENT PANEL ASSEMBLY - REMOVAL).
(3) Place the instrument panel face down on a
suitable work surface. Be certain to take the proper
precautions to protect the face of the instrument
panel from cosmetic damage.
(4) Remove the fasteners that secure the demister
ducts to the instrument panel armature.
(5) Disengage the demister ducts from the demis-
ter outlets.
(6) Remove the demister ducts from the instru-
ment panel.
INSTALLATION
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.
(1) Position the demister ducts to the instrument
panel.(2) Engage the demister ducts to the demister out-
lets.
(3) Install the fasteners that secure the demister
ducts to the instrument panel armature.
(4) Reinstall the instrument panel into the vehicle.
(Refer to 23 - BODY/INSTRUMENT PANEL/IN-
STRUMENT PANEL ASSEMBLY - INSTALLA-
TION).
(5) Reconnect the battery negative cable.
INSTRUMENT PANEL DUCTS
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 ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel from the vehicle
(Refer to 23 - BODY/INSTRUMENT PANEL/IN-
STRUMENT PANEL ASSEMBLY - REMOVAL).
(3) Place the instrument panel face down on a
suitable work surface. Be certain to take the proper
precautions to protect the face of the instrument
panel from cosmetic damage.
(4) Remove the screws that secure the panel ducts
to the instrument panel armature.
(5) Disengage the panel ducts from the panel out-
lets.
(6) Remove the panel ducts from the instrument
panel.
INSTALLATION
(1) Position the panel ducts to the instrument
panel.
(2) Engage the panel ducts to the panel outlets.
(3) Install the screws that secure the panel ducts
to the instrument panel armature.
(4) Reinstall the instrument panel into the vehicle
(Refer to 23 - BODY/INSTRUMENT PANEL/IN-
STRUMENT PANEL ASSEMBLY - INSTALLA-
TION).
(5) Reconnect the battery negative cable.
RSDISTRIBUTION - FRONT24-55

INSTALLATION
(1) Position the discharge line into the engine com-
partment.
(2) Remove the tape or plugs from the compressor
discharge port and the discharge line fitting.
(3) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the discharge line fit-
ting.
(4) Install a new dual plane seal and reconnect the
discharge line fitting to the compressor discharge
port on the top of the compressor.
(5) Install the nut that secures the discharge line
fitting to the compressor. Tighten the nut to 23 N´m
(17 ft. lbs.).
(6) Remove the tape or plugs from the condenser
inlet port and the discharge line fitting.
(7) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the discharge line fit-
ting.
(8) Install a new dual plane seal and reconnect the
discharge line fitting to the condenser inlet port on
the right side of the cooling module.
(9) Install the nut that secures the discharge line
fitting to the condenser. Tighten the nut to 23 N´m
(17 ft. lbs.).
(10) Position the radiator sight shield onto the
radiator closure panel crossmember.
(11) Install the five small screws that secure the
front fascia grille inserts to the radiator sight shield.
Tighten the screws to 2 N´m (17 in. lbs.).
(12) Install and tighten the two large screws that
secure the front fascia and the outboard ends of the
radiator sight shield to the radiator closure panel
crossmember. Tighten the screws to 6 N´m (53 in.
lbs.).
(13) Evacuate the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM EVACUATE).
(14) Charge the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM CHARGE).
A/C EVAPORATOR
DESCRIPTION
The A/C evaporator is located in the HVAC hous-
ing, behind the instrument panel. The evaporator is
positioned in the housing so that all air that enters
the housing must pass over the fins of the evaporator
coils before it is distributed through the system ducts
and outlets. However, air passing over the evaporator
fins will only be conditioned when the compressor isengaged and circulating refrigerant through the
evaporator tubes.
OPERATION
Refrigerant enters the A/C evaporator from the
expansion valve as a low-temperature, low-pressure
liquid. As air flows over the fins of the evaporator,
the humidity in the air condenses on the fins, and
the heat from the air is absorbed by the refrigerant.
Heat absorption causes the refrigerant to boil and
vaporize. The refrigerant becomes a low-pressure gas
when it leaves the evaporator.
The A/C evaporator cannot be repaired and, if
faulty or damaged, it must be replaced.
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 ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Remove the HVAC housing (Refer to 24 -
HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - REMOVAL).
(2) Disassemble the HVAC housing to access the
evaporator (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION/HVAC HOUSING - DIS-
ASSEMBLY).
(3) Carefully lift the evaporator and its foam wrap
out of the lower half of the HVAC housing as a unit.
Be certain not to lose the clam shell type rubber seal
that is fitted to the evaporator inlet and outlet tubes
where they exit the HVAC housing.
INSTALLATION
NOTE: If the evaporator is being replaced, add 50
milliliters (1.8 fluid ounces) of refrigerant oil to the
refrigerant system. Use only refrigerant oil of the
type recommended for the compressor in the vehi-
cle.
(1) Carefully lower the evaporator and its foam
wrap into the lower half of the HVAC housing as a
unit. Be certain that the clam shell type rubber seal
24 - 80 PLUMBING - FRONTRS
A/C DISCHARGE LINE (Continued)

(8) Lubricate new rubber O-ring seals with clean
refrigerant oil and install them on the front liquid
line rear section and suction line fittings for the
expansion valve.
(9) Connect the liquid line and suction line fittings
to the expansion valve.
(10) Install the nut that secures the suction line
and liquid line fittings to the stud on the expansion
valve. Tighten the nut to 23 N´m (17 ft. lbs.).
(11) Remove the tape or plugs from the liquid line
rear section fitting and the receiver/drier outlet port.
(12) Lubricate a new rubber O-ring seal with clean
refrigerant oil and install it on the liquid line fitting.
(13) Connect the liquid line fitting to the receiver/
drier outlet port.
(14) Install the screw that secures the liquid line
fitting to the receiver/drier. Tighten the screw to 11
N´m (97 in. lbs.).
(15) Connect the wire harness connector to the A/C
pressure transducer.
(16) Connect the drain tube to the wiper module
drain on the right side of the engine compartment.
(17) Install the air cleaner housing.
(18) Reconnect the battery negative cable.
(19) Evacuate the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM EVACUATE).
(20) Charge the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
FRONT/REFRIGERANT - STANDARD PROCE-
DURE - REFRIGERANT SYSTEM CHARGE).
HEATER CORE
DESCRIPTION
The heater core is located in the distribution hous-
ing, which is attached to the HVAC housing, behind
the instrument panel. It is a heat exchanger made of
rows of tubes and fins. One end of the core is fitted
with a molded plastic tank, which includes integral
heater core inlet and outlet ports. Removable heater
core tubes attach to the ports by use of a sealing
plate secured with a screw to the heater core tank.
This removable heater core tube arrangement allows
the heater core to be serviced without removing the
HVAC housing from the vehicle.
OPERATION
Engine coolant is circulated through heater hoses
to the heater core at all times. As the coolant flows
through the heater core, heat removed from the
engine is transferred to the heater core fins and
tubes. Air directed through the heater core picks up
the heat from the heater core fins. The blend doorallows control of the heater output air temperature
by regulating the amount of air that is flowing
through the heater core within the HVAC housing.
The heater core cannot be repaired and, if faulty or
damaged, it must be replaced.
REMOVAL
REMOVAL - HEATER CORE TUBES
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.
(1) Drain the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM DRAIN).
(2) Disconnect and isolate the battery negative
cable.
(3) Disconnect the heater hoses from the heater
core tubes (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING/HEATER INLET HOSE -
REMOVAL) and (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING/HEATER RETURN
HOSE - REMOVAL).
(4) Remove the silencer from beneath the driver
side end of the instrument panel.
NOTE: Take the proper precautions to protect the
carpeting below the heater core from spilled engine
coolant and have absorbent toweling readily avail-
able to clean up any spills.
(5) Remove the screw that secures the heater core
tube sealing plate to the heater core supply and
return ports (Fig. 14).
(6) Push both heater core tubes simultaneously
toward the dash panel far enough to disengage their
fittings from the heater core supply and return ports.
(7) Install plugs in, or tape over the opened heater
core tube fittings and both heater core ports.
(8) Pull both heater core tubes simultaneously
slightly away from the distribution housing and rear-
ward far enough to disengage the engine compart-
ment ends of the tubes from the dash panel seal.
RSPLUMBING - FRONT24-83
EXPANSION VALVE (Continued)

(9) Remove the heater core tubes and sealing plate
as a unit from beneath the instrument panel.
(10) Use absorbent toweling to clean up any
engine coolant spills from the preceding operation.
REMOVAL - HEATER CORE
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.
(1) Remove the silencer boot fasteners located
around the base of the lower steering shaft from the
dash panel so that it may be pushed aside.
(2) Remove the brake lamp switch from its mount-
ing bracket (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/BRAKE LAMP SWITCH -
REMOVAL).
(3) Disconnect the power brake booster input rod
(push rod) from the pin on the brake pedal arm
(Refer to 5 - BRAKES - ABS/HYDRAULIC/ME-CHANICAL/POWER BRAKE BOOSTER -
REMOVAL).
(4) Remove the heater core tubes (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/
HEATER CORE - REMOVAL).
(5) Remove the two screws that secure the heater
core mounting plate to the distribution housing.
(6) While pulling the accelerator pedal upward
(Fig. 15) and pushing the brake pedal downward
(Fig. 16) far enough for clearance, pull the heater
core out of the distribution housing.
(7) Use absorbent toweling to mop up any engine
coolant spills from the preceding operation. Also, if
the heater core was leaking, use absorbent toweling
and reach into the heater core opening to mop up
any residual engine coolant within the distribution
housing.
Fig. 14 Heater Core Tubes - LHD Shown, RHD
Typical
1 - SEAL
2 - HEATER CORE TUBES
3 - SCREW
4 - HEATER CORE
5 - DISTRIBUTION HOUSING
6 - SEALING PLATE
Fig. 15 Accelerator Pedal - LHD Shown, RHD Typical
1 - HEATER CORE
Fig. 16 Brake Pedal - LHD Shown, RHD Typical
1 - HEATER CORE
2 - BRAKE PEDAL
24 - 84 PLUMBING - FRONTRS
HEATER CORE (Continued)

INSTALLATION
INSTALLATION - HEATER CORE TUBES
(1) Remove the plugs or tape from both heater core
tube fittings and both heater core ports.
(2) Position the heater core tubes and sealing plate
as a unit beneath the instrument panel.
(3) Align the engine compartment ends of both
heater core tubes with the openings in the dash
panel seal and push them simultaneously forward
through the seal far enough to engage the heater
core ends of the tubes with the heater core supply
and return ports.
(4) Position both heater core tubes and the sealing
plate simultaneously to the heater core supply and
return ports.
NOTE: The heater core tubes each have a slot that
must be indexed to a location tab within each of the
heater core ports. Adjust the position of the tubes
as required so that the sealing plate fits flush
against the heater core supply and return ports,
which indicates that the tubes are properly indexed.
(5) Index both heater core tubes to the heater core
ports.
(6) Install the screw that secures the heater core
tube sealing plate to the heater core supply and
return ports. Tighten the screw to 3 N´m (27 in. lbs.).
(7) Install the silencer under the driver side end of
the instrument panel.
(8) Connect the heater hoses to the heater hose
tubes (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING/HEATER INLET HOSE - INSTAL-
LATION) and(Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING/HEATER RETURN
HOSE - INSTALLATION).
(9) Reconnect the battery negative cable.
(10) Refill the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM REFILL).
INSTALLATION - HEATER CORE
(1) While pushing the brake pedal downward and
pulling the accelerator pedal upward far enough for
clearance, slide the heater core into the distribution
housing.
(2) Install the two screws that secure the heater
core mounting plate to the distribution housing.
Tighten the screws to 2 N´m (17 in. lbs.).
(3) Install the heater core tubes (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/
HEATER CORE - INSTALLATION).
(4) Reconnect the power brake booster input rod
(push rod) to the pin on the brake pedal arm (Referto 5 - BRAKES/HYDRAULIC/MECHANICAL/
POWER BRAKE BOOSTER - INSTALLATION).
(5) Reinstall the brake lamp switch into its mount-
ing bracket (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/BRAKE LAMP SWITCH -
INSTALLATION).
(6) Reinstall the silencer boot around the base of
the lower steering shaft on the dash panel.
(7) Reconnect the battery negative cable.
(8) Refill the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM REFILL).
(9) Operate system for two thermostat cycles to
assure the elimination of any air that may be
trapped within the cooling system.
HEATER INLET HOSE
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).
NOTE: The heater inlet hose is constructed from
formed steel tubing and rubber hoses. Depending
on application, the ends are secured to the heater
core, engine oil cooler or the engine by spring ten-
sion clamps.
(1) Drain the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE - COOLING
SYSTEM DRAIN).
(2) Using spring tension clamp pliers, compress
and slide the clamps off of each end of the hose being
removed (Fig. 17), (Fig. 18) or (Fig. 19).
CAUTION:
DO NOT apply excessive pressure on heater tubes
or connections when removing heater hoses.
Excessive pressure may damage or deform the
tubes/heater core, causing an engine coolant leak.
(3) Disconnect each hose end by carefully twisting
the hose back and forth on the tube or nipple, while
gently pulling it away from the end of the tube or
nipple.
NOTE:
Replacement of the heater inlet hoses will be
required if the hose ends are cut for removal.
(4) If necessary, carefully cut the hose end and
peel the hose off of the tube or nipple.
RSPLUMBING - FRONT24-85
HEATER CORE (Continued)

The following is a list of the monitored compo-
nents:
²Comprehensive Components
²Oxygen Sensor Monitor
²Oxygen Sensor Heater Monitor
²Catalyst Monitor
COMPREHENSIVE COMPONENTS
Along with the major monitors, OBD II requires
that the diagnostic system monitor any component
that could affect emissions levels. In many cases,
these components were being tested under OBD I.
The OBD I requirements focused mainly on testing
emissions-related components for electrical opens and
shorts.
However, OBD II also requires that inputs from
powertrain components to the PCM be tested for
rationality, and that outputs to powertrain compo-
nents from the PCM be tested forfunctionality.
Methods for monitoring the various Comprehensive
Component monitoring include:
(1) Circuit Continuity
²Open
²Shorted high
²Shorted to ground
(2) Rationality or Proper Functioning
²Inputs tested for rationality
²Outputs tested for functionality
NOTE: Comprehensive component monitors are
continuous. Therefore, enabling conditions do not
apply.
Input RationalityÐWhile input signals to the
PCM are constantly being monitored for electrical
opens and shorts, they are also tested for rationality.
This means that the input signal is compared against
other inputs and information to see if it makes sense
under the current conditions.
PCM sensor inputs that are checked for rationality
include:
²Manifold Absolute Pressure (MAP) Sensor
²Oxygen Sensor (O2S)
²Engine Coolant Temperature (ECT) Sensor
²Camshaft Position (CMP) Sensor
²Vehicle Speed Sensor
²Crankshaft Position (CKP) Sensor
²Intake/inlet Air Temperature (IAT) Sensor
²Throttle Position (TPS) Sensor
²Ambient Temperature Sensors
²Power Steering Switch
²Oxygen Sensor Heater
²Brake Switch
²Leak Detection Pump Switch or NVLD switch (if
equipped)
²P/N SwitchOutput FunctionalityÐPCM outputs are tested
for functionality in addition to testing for opens and
shorts. When the PCM provides a voltage to an out-
put component, it can verify that the command was
carried out by monitoring specific input signals for
expected changes. For example, when the PCM com-
mands the Idle Air Control (IAC) Motor to a specific
position under certain operating conditions, it expects
to see a specific (target) idle speed (RPM). If it does
not, it stores a DTC.
PCM outputs monitored for functionality include:
²Fuel Injectors
²Ignition Coils
²Idle Air Control
²Purge Solenoid
²EGR Solenoid (if equipped)
²LDP Solenoid or NVLD solenoid (if equipped)
²Radiator Fan Control
²Trans Controls
OXYGEN SENSOR (O2S) MONITOR
DESCRIPTIONÐEffective 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 operating temperature 300É to 350ÉC
(572É to 662ÉF), the sensor generates a voltage that
is inversely proportional to the amount of oxygen in
the exhaust. When there is a large amount of oxygen
in the exhaust caused by a lean condition, the sensor
produces a low voltage, below 450 mV. When the oxy-
gen content is lower, caused by a rich condition, the
sensor produces a higher voltage, above 450mV (volt-
ages are offset by 2.5 volts on NGC vehicles).
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 (Big Slope)
²Reduced output voltage (Half Cycle)
²Heater Performance
Slow Response Rate (Big Slope)ÐResponse rate
is the time required for the sensor to switch from
lean to rich signal output once it is exposed to a
richer than optimum A/F mixture or vice versa. As
the PCM adjusts the air/fuel ratio, the sensor must
be able to rapidly detect the change. As the sensor
ages, it could take longer to detect the changes in the
oxygen content of the exhaust gas. The rate of
change that an oxygen sensor experiences is called
25 - 2 EMISSIONS CONTROLRS
EMISSIONS CONTROL (Continued)

ªBig Slopeº. The PCM checks the oxygen sensor volt-
age in increments of a few milliseconds.
Reduced Output Voltage (Half Cycle)ÐThe
output voltage of the O2S ranges from 0 to 1 volt
(voltages are offset by 2.5 volts on NGC vehicles). A
good sensor can easily generate any output voltage in
this range as it is exposed to different concentrations
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. Each
time the voltage signal surpasses the threshold, a
counter is incremented by one. This is called the Half
Cycle Counter.
Heater PerformanceÐThe heater is tested by a
separate monitor. Refer to the Oxygen Sensor Heater
Monitor.
OPERATIONÐAs the Oxygen Sensor signal
switches, the PCM monitors the half cycle and big
slope signals from the oxygen sensor. If during the
test neither counter reaches a predetermined value, a
malfunction is entered and Freeze Frame data is
stored. Only one counter reaching its predetermined
value is needed for the monitor to pass.
The Oxygen Sensor Monitor is a two trip monitor
that is tested only once per trip. When the Oxygen
Sensor fails the test in two consecutive trips, the
MIL is illuminated and a DTC is set. The MIL is
extinguished when the Oxygen Sensor monitor
passes in three consecutive trips. The DTC is erased
from memory after 40 consecutive warm-up cycles
without test failure.
Enabling ConditionsÐThe following conditions
must typically be met for the PCM to run the oxygen
sensor monitor:
²Battery voltage
²Engine temperature
²Engine run time
²Engine run time at a predetermined speed
²Engine run time at a predetermined speed and
throttle opening
²Transmission in gear and brake depressed (auto-
matic only)
²Fuel system in Closed Loop
²Long Term Adaptive (within parameters)
²Power Steering Switch in low PSI (no load)
²Engine at idle
²Fuel level above 15%
²Ambient air temperature
²Barometric pressure
²Engine RPM within acceptable range of desired
idle
Pending ConditionsÐThe Task Manager typi-
cally does not run the Oxygen Sensor Monitor if over-
lapping monitors are running or the MIL is
illuminated for any of the following:²Misfire Monitor
²Front Oxygen Sensor and Heater Monitor
²MAP Sensor
²Vehicle Speed Sensor
²Engine Coolant Temperature Sensor
²Throttle Position Sensor
²Engine Controller Self Test Faults
²Cam or Crank Sensor
²Injector and Coil
²Idle Air Control Motor
²EVAP Electrical
²EGR Solenoid Electrical (if equipped)
²Intake/inlet Air Temperature
²5 Volt Feed
ConflictÐThe Task Manager does not run the
Oxygen Sensor Monitor if any of the following condi-
tions are present:
²A/C ON (A/C clutch cycling temporarily sus-
pends monitor)
²Purge flow in progress
²Ethanol content learn is taking place and the
ethanol used once flag is set (if equipped)
SuspendÐThe Task Manager suspends maturing
a fault for the Oxygen Sensor Monitor if any of the
following are present:
²Oxygen Sensor Heater Monitor, Priority 1
²Misfire Monitor, Priority 2
OXYGEN SENSOR HEATER MONITOR
DESCRIPTIONÐIf there is an oxygen sensor
(O2S) DTC as well as a O2S heater DTC, the O2S
fault MUST be repaired first. After the O2S fault is
repaired, verify that the heater circuit is operating
correctly.
The voltage readings taken from the O2S are very
temperature sensitive. The readings are not accurate
below a sensor temperature of 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 heater element itself is not tested. The sensor
output is used to test the heater by isolating the
effect of the heater element on the O2S output volt-
age from the other effects. The resistance is normally
between 100 ohms and 4.5 megaohms. When oxygen
sensor temperature increases, the resistance in the
internal circuit decreases. The PCM sends a 5 volts
biased signal through the oxygen sensors to ground
this monitoring circuit. As the temperature increases,
resistance decreases and the PCM detects a lower
voltage at the reference signal. Inversely, as the tem-
perature decreases, the resistance increases and the
PCM detects a higher voltage at the reference signal.
The O2S circuit is monitored for a drop in voltage.
RSEMISSIONS CONTROL25-3
EMISSIONS CONTROL (Continued)

ALIGNMENT - STANDARD PROCEDURE,
FRONT WIPER ARM...................8R-8
ALIGNMENT - STANDARD PROCEDURE,
HEADLAMP UNIT.....................8L-13
ALIGNMENT - STANDARD PROCEDURE,
WHEEL.............................2-52
ALIGNMENT, SPECIFICATIONS - WHEEL....2-56
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
ANCHOR - DESCRIPTION, CHILD
RESTRAINT..........................8O-4
ANCHOR - OPERATION, CHILD
RESTRAINT..........................8O-4
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
ANTILOCK BRAKE SYSTEM -
DESCRIPTION........................5-75
ANTILOCK BRAKE SYSTEM - OPERATION . . 5-76
ANTILOCK BRAKE SYSTEM BLEEDING -
STANDARD PROCEDURE................5-78
ANTILOCK BRAKE SYSTEM (EXPORT) -
DESCRIPTION........................5-75
A-PILLAR LOWER EXTENSION TRIM -
INSTALLATION.......................23-74
A-PILLAR LOWER EXTENSION TRIM -
REMOVAL..........................23-74
A-PILLAR TRIM - INSTALLATION........23-74
A-PILLAR TRIM - REMOVAL............23-74
A-PILLAR-HEADER, OR B-PILLAR -
INSTALLATION.......................23-17
A-PILLAR-HEADER, OR B-PILLAR -
REMOVAL
..........................23-17
APPLIQUE - INSTALLATION
.............23-14
APPLIQUE - REMOVAL
................23-14
ARM - DESCRIPTION, LOWER CONTROL
. . . 2-12
ARM - INSPECTION, LOWER CONTROL
....2-14
ARM - INSTALLATION, LOWER CONTROL
. . 2-16
ARM - INSTALLATION, REAR WIPER
.....8R-10
ARM - INSTALLATION, TORQUE
..........3-44
ARM - OPERATION, LOWER CONTROL
.....2-12
ARM - REMOVAL, LOWER CONTROL
......2-12
ARM - REMOVAL, REAR WIPER
.........8R-10
ARM - REMOVAL, TORQUE
..............3-44
ARM ALIGNMENT - STANDARD
PROCEDURE, FRONT WIPER
............8R-8ARM (REAR BUSHING - HYDRO) -
ASSEMBLY, LOWER CONTROL...........2-14
ARM (REAR BUSHING - HYDRO) -
DISASSEMBLY, LOWER CONTROL........2-14
ARM (REAR BUSHING - STANDARD) -
ASSEMBLY, LOWER CONTROL...........2-14
ARM (REAR BUSHING - STANDARD) -
DISASSEMBLY, LOWER CONTROL........2-13
ARMREST - INSTALLATION.............23-91
ARMREST - REMOVAL................23-91
ARMS - DESCRIPTION, ROCKER....9-109,9s-26
ARMS - INSPECTION, ROCKER...........9-35
ARMS - INSTALLATION, FRONT WIPER....8R-9
ARMS - INSTALLATION, ROCKER.........9-35
ARMS - OPERATION, ROCKER.....9-109,9s-26
ARMS - REMOVAL, FRONT WIPER........8R-9
ARMS - REMOVAL, ROCKER.............9-34
ARMS AND SHAFT - ASSEMBLY,
ROCKER.......................9-109,9s-27
ARMS AND SHAFT - DISASSEMBLY,
ROCKER.......................9-109,9s-27
ARMS AND SHAFT - INSTALLATION,
ROCKER.......................9-110,9s-28
ARMS AND SHAFT - REMOVAL, ROCKER . 9-109,
9s-27
ASSIST HANDLE - INSTALLATION........23-74
ASSIST HANDLE - REMOVAL...........23-74
ASSIST STRAP - INSTALLATION, FRONT
SEATBACK..........................23-92
ASSIST STRAP - REMOVAL, FRONT
SEATBACK..........................23-92
ATC - OPERATION, THREE ZONE.........24-5
ATTACHED - INSTALLATION, EXTERIOR
NAME PLATES - ADHESIVE.............23-51
ATTACHED - INSTALLATION, EXTERIOR
NAME PLATES - TAPE.................23-51
ATTACHED - REMOVAL, EXTERIOR NAME
PLATES - ADHESIVE..................23-51
ATTACHED - REMOVAL, EXTERIOR NAME
PLATES - TAPE ......................23-51
AUDIO - DIAGNOSIS AND TESTING.......8A-2
AUDIO/VIDEO - DESCRIPTION...........8A-1
AUDIO/VIDEO - OPERATION.............8A-2
AUTO SHUT DOWN RELAY -
DESCRIPTION.........................8I-3
AUTO SHUT DOWN RELAY - OPERATION . . . 8I-3
AUTOMATIC ADJUSTER - DIAGNOSIS
AND TESTING, DRUM BRAKE.......5-13,5s-13
AUTOMATIC ADJUSTER TENSION
RELEASE - STANDARD PROCEDURE,
PARKING BRAKE.................5-58,5s-61
AUTOMATIC ADJUSTER TENSION RESET
- STANDARD PROCEDURE, PARKING
BRAKE.........................5-59,5s-61
AUTOMATIC DAY / NIGHT MIRROR -
DESCRIPTION.......................8N-47
AUTOMATIC DAY / NIGHT MIRROR -
DIAGNOSIS AND TESTING.............8N-47
AUTOMATIC DAY / NIGHT MIRROR -
OPERATION.........................8N-47
AUTOMATIC TEMPERATURE CONTROL
(ATC) - INSTALLATION................24-29
AUTOMATIC TEMPERATURE CONTROL
(ATC) - REMOVAL....................24-28
AUTOMATIC TEMPERATURE CONTROL
SYSTEM - OPERATION
...............24-112
AUTOMATIC THREE ZONE -
DESCRIPTION
........................24-3
AUTOMATIC TRANSAXLE - ASSEMBLY,
41TE
............................21s-184
AUTOMATIC TRANSAXLE -
DESCRIPTION, 40TE
.................21s-25
AUTOMATIC TRANSAXLE -
DESCRIPTION, 41TE
.................21-117
AUTOMATIC TRANSAXLE -
DISASSEMBLY, 41TE
................21s-166
AUTOMATIC TRANSAXLE - OPERATION,
40TE
.............................21s-27
AUTOMATIC TRANSAXLE - OPERATION,
41TE
.............................21-119
AUTOMATIC TRANSAXLE, SPECIAL
TOOLS - 41TE
......................21-183
AUTOMATIC/MANUAL TRANSAXLE FLUID
- DESCRIPTION
........................0-4
AUTOSTICK SWITCH - DESCRIPTION
....21-189
AUTOSTICK SWITCH - OPERATION
......21-189
AWD - INSTALLATION
..................2-45AWD - INSTALLATION, REAR WHEEL
SPEED SENSOR.......................5-80
AWD - INSTALLATION, SPRING..........2-39
AWD - REMOVAL.....................2-45
AWD - REMOVAL, REAR WHEEL SPEED
SENSOR............................5-80
AWD - REMOVAL, SPRING..............2-38
AWD, HEAVY DUTY, CARGO -
INSTALLATION........................2-36
AWD, HEAVY DUTY, CARGO - REMOVAL . . . 2-36
AWD POWER TRANSFER UNIT FLUID -
DESCRIPTION.........................0-6
AWD REAR DRIVELINE MODULE FLUIDS
- DESCRIPTION........................0-6
AXLE SEALS - INSTALLATION...........21-61
AXLE SEALS - REMOVAL..............21-61
B OR C-PILLAR - INSTALLATION, SEAT
BELT HEIGHT ADJUSTER..............8O-13
B OR C-PILLAR - REMOVAL, SEAT BELT
HEIGHT ADJUSTER...................8O-13
BACK - INSTALLATION, BENCH SEAT....23-103
BACK - INSTALLATION, FRONT SEAT.....23-92
BACK - QUAD BUCKET - INSTALLATION,
BUCKET SEAT.......................23-99
BACK - QUAD BUCKET - REMOVAL,
BUCKET SEAT.......................23-98
BACK - REMOVAL, BENCH SEAT........23-103
BACK - REMOVAL, FRONT SEAT.........23-92
BACK COVER - INSTALLATION, BENCH
SEAT .............................23-103
BACK COVER - REMOVAL, BENCH SEAT . . 23-103
BACK HINGE - REMOVAL, BENCH SEAT . . 23-102
BACK HINGE COVERS - QUAD BUCKET,
50/50 SPLIT, BENCH - INSTALLATION,
SEAT .............................23-101
BACK HINGE COVERS - QUAD BUCKET,
50/50 SPLIT, BENCH - REMOVAL, SEAT . . 23-101
BACKING PLATE - INSTALLATION,
STEERING COLUMN COVER............23-70
BACKING PLATE - REMOVAL, STEERING
COLUMN COVER.....................23-70
BACK-UP LAMP SWITCH -
INSTALLATION.......................21-62
BACK-UP LAMP SWITCH - REMOVAL.....21-62
BAG RETAINER - INSTALLATION,
PLASTIC GROCERY..................23-105
BAG RETAINER - REMOVAL, PLASTIC
GROCERY.........................23-104
BALANCE - STANDARD PROCEDURE,
TIRE AND WHEEL.....................22-5
BALANCE SHAFTS AND CARRIER
ASSEMBLY - DESCRIPTION.............9-69
BALANCE SHAFTS AND CARRIER
ASSEMBLY - INSTALLATION.............9-72
BALANCE SHAFTS AND CARRIER
ASSEMBLY - OPERATION...............9-69
BALANCE SHAFTS AND CARRIER
ASSEMBLY - REMOVAL.................9-69
BALL BEARING - INSTALLATION, END
COVER.............................21-10
BALL BEARING - REMOVAL, END COVER . . . 21-9
BALL JOINT - DESCRIPTION, LOWER......2-10
BALL JOINT - DIAGNOSIS AND TESTING,
LOWER.............................2-10
BALL JOINT - OPERATION, LOWER.......2-10
BAR - DESCRIPTION, STABILIZER....2-16,2-45
BAR - DESCRIPTION, TRACK............2-46
BAR - INSPECTION, STABILIZER..........2-18
BAR - INSTALLATION, STABILIZER........2-18
BAR - INSTALLATION, TRACK
............2-46
BAR - OPERATION, STABILIZER
......2-17,2-45
BAR - OPERATION, TRACK
..............2-46
BAR - REMOVAL, STABILIZER
...........2-17
BAR - REMOVAL, TRACK
...............2-46
BAR CUSHION - INSTALLATION,
STABILIZER
...........................2-4
BAR CUSHION - REMOVAL, STABILIZER
....2-4
BASE BRAKE BLEEDING - STANDARD
PROCEDURE
......................5-7,5s-7
BASE BRAKE SYSTEM - DIAGNOSIS AND
TESTING
.........................5-4,5s-4
BASE BRAKE SYSTEM, SPECIAL TOOLS
. . . 5-10,
5s-9
BASE BRAKES - DESCRIPTION
........5-3,5s-3
BASE BRAKES - OPERATION
..........5-3,5s-3
BASE BRAKES (EXPORT) - DESCRIPTION
. . . 5-3,
5s-3
2 INDEXRS
Description Group-Page Description Group-Page Description Group-Page