ignition CHRYSLER VOYAGER 2004 Service Manual

heater control has detected a failure and a Diagnostic
Trouble Code (DTC) has been set. Refer to Body
Diagnostic Procedures to perform further diagnosis.
The LEDs or graphics will continue to flash even
after the ignition switch is cycled Off and On, until a
successful calibration is completed or until the vehi-
cle has been driven about 13 kilometers (8 miles).
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 center bezel from the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL -
REMOVAL).
(3) Place the instrument panel center bezel unit
face down on a suitable work surface. Take the
proper precautions to protect the center bezel from
cosmetic damage.
(4) If the vehicle is equipped with the optional
Automatic Temperature Control (ATC) system, dis-
connect the infrared sensor jumper harness connector
from the receptacle on the back of the A/C-heater
control (Fig. 9).
(5) Remove the six screws that secure the A/C-
heater control to the back of the instrument panel
center bezel.
(6) Remove the A/C-heater control from the instru-
ment panel center bezel.
INSTALLATION
(1) Position the A/C-heater control onto the back of
instrument panel center bezel.
(2) Install the six screws that secure the A/C-
heater control to the back of the instrument panel
center bezel. Tighten the screws to 2 N´m (17 in.
lbs.).
(3) If the vehicle is equipped with the optional
ATC system, reconnect the infrared sensor jumper
harness connector to A/C-heater control.(4) Install the center bezel onto the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - INSTAL-
LATION).
(5) Reconnect the battery negative cable.
A/C PRESSURE TRANSDUCER
DESCRIPTION
The A/C pressure transducer is a switch that is
installed on a fitting located on the refrigerant liquid
line between the receiver/drier and the expansion
valve in the right rear corner of the engine compart-
ment. An internally threaded hex fitting on the
transducer connects it to the externally threaded
Schrader-type fitting on the liquid line. A rubber
O-ring seals the connection between the transducer
and the liquid line fitting. Three terminals within a
molded plastic connector receptacle on the top of the
transducer connect it to the vehicle electrical system
through a wire lead and connector of the headlamp
and dash wire harness.
The A/C pressure transducer cannot be adjusted or
repaired and, if faulty or damaged, it must be
replaced.
OPERATION
The A/C pressure transducer monitors the pres-
sures in the high side of the refrigerant system
through its connection to a fitting on the liquid line.
The transducer will change its internal resistance in
response to the pressures it monitors. The power-
train control module (PCM) provides a five volt ref-
Fig. 9 A/C-Heater Control
1 - INFRARED SENSOR CONNECTOR (ATC ONLY)
2 - INFRARED SENSOR HARNESS (ATC ONLY)
3 - A/C-HEATER CONTROL AREA
4 - SCREW (6)
5- INSTRUMENT PANEL CENTER BEZEL
RSCONTROLS - FRONT24-21
A/C HEATER CONTROL (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)

CABIN HEATER
TABLE OF CONTENTS
page page
CABIN HEATER
DESCRIPTION........................112
OPERATION
OPERATION - MANUAL TEMPERATURE
CONTROL SYSTEM...................112
OPERATION - AUTOMATIC TEMPERATURE
CONTROL SYSTEM...................112
DIAGNOSIS AND TESTING - DIESEL
SUPPLEMENTAL CABIN HEATER........113
AIR INTAKE PIPE
REMOVAL............................113
INSTALLATION........................114
EXHAUST TUBE
REMOVAL............................114
INSTALLATION........................115FUEL DOSING PUMP
DESCRIPTION........................115
OPERATION..........................115
REMOVAL............................115
INSTALLATION........................116
FUEL LINE
STANDARD PROCEDURE - CLEANING.....117
REMOVAL............................117
INSTALLATION........................118
HEATER UNIT
REMOVAL............................118
INSTALLATION........................119
SUPPLEMENTAL DIESEL HEATER WIRING
REMOVAL............................119
INSTALLATION........................119
CABIN HEATER
DESCRIPTION
Vehicles equipped with the diesel engine are also
equipped with a supplemental cabin heater. This
cabin heater is mounted under the vehicle and oper-
ates similar to an oil fired furnace. The heater burns
small amounts of fuel to provide additional heat to
the coolant. Coolant is routed from the engine, to the
supplemental cabin heater and then to the front
heater core. This provides additional heat to the pas-
senger compartment. The supplemental cabin heater
system is interfaced to the vehicles on-board com-
puter systems and DRBIIItdiagnostics.
The supplemental cabin heater has an electronic
control module that monitors the heat output of the
heater. The cabin heater operates at full load (5 kW),
half load or idle mode (no additional heat) depending
on engine coolant temperature.
OPERATION
OPERATION - MANUAL TEMPERATURE
CONTROL SYSTEM
The supplemental cabin heater is activated via the
temperature slide control or knob on the A/C-heater
control when equipped with the manual temperature
control (MTC) system. If the slide control or knob is
moved to or above the upper set point the cabin
heater is activated. The cabin heater can operate in a
full or partial load range as well as an idle mode alldependent on the engine coolant temperature. The
cabin heater will also turn off if the A/C-heater tem-
perature control is lowered to less than the lower set
point. The cabin heater can take up to three minutes
to completely shut down when either the heater tem-
perature is set below the lower set point or the vehi-
cle ignition is shut down.
NOTE: Do not apply a strong vacuum source such
as a garage ventilation system directly on the sup-
plemental cabin heater exhaust line. Too strong of a
vacuum can prevent the supplemental cabin heater
from starting. If required, place the vacuum source
at least 75 mm (3 in.) away from the exhaust line.
The supplemental cabin heater only operates when
the engine is running, the mileage exceeds 8 kilome-
ter (5 mph) and the fuel tank volume exceeds 1/8 of a
tank. The supplemental heater control module moni-
tors blower speed and combustion during its start-up.
The cabin heater should operate if the coolant tem-
perature is below 40É C (104É F).
OPERATION - AUTOMATIC TEMPERATURE
CONTROL SYSTEM
The automatic temperature control (ATC) system
will activate the supplemental cabin heater based on
engine coolant temperature and interior component
settings. The cabin heater can operate in a full or
partial load range as well as an idle mode all depen-
dent on the engine coolant temperature. The cabin
heater will also turn off if the A/C-heater tempera-
ture control is lowered to less than the lower set
24 - 112 CABIN HEATERRS

point. The cabin heater can take up to three minutes
to completely shut down when either the heater tem-
perature is set below the lower set point or the vehi-
cle ignition is shut down.
NOTE: Do not apply a strong vacuum source such
as a garage ventilation system directly on the sup-
plemental cabin heater exhaust line. Too strong of a
vacuum can prevent the supplemental cabin heater
from starting. If required, place the vacuum source
at least 75 mm (3 in.) away from the exhaust line.
The supplemental cabin heater only operates when
the engine is running, the mileage exceeds 8 kilome-ter (5 mph) and the fuel tank volume exceeds 1/8 of a
tank. The supplemental heater control module moni-
tors blower speed and combustion during its start-up.
The cabin heater should operate if the coolant tem-
perature is below 40É C (104É F).
DIAGNOSIS AND TESTING - DIESEL
SUPPLEMENTAL CABIN HEATER
Refer to the Symptoms Diagnosis table for basic
checks of the diesel fueled supplemental cabin heater.
SYMPTOMS DIAGNOSIS
Symptom Possible Causes
Smell of diesel fuel. Check cabin heater system integration in vehicle's fuel system. Check
fuel lines for leakage, kinks or obstructions. If OK, Inspect the inlet
muffler, drain as necessary. Re-test the cabin heater and re-inspect.
Inspect the exhaust tube and cabin heater for the presence of external
fuel. If presence of external fuel is observed on the heater unit or in the
exhaust tube or after draining and testing. Remove the cabin heater
from vehicle and repair or replace components as required.
Heater does not achieve full load
operation.Check cabin heater operation with DRBIIITscan tool and replace
components as required.
Continuous white smoke from heater
exhaust during combustion operation.Check cabin heater operation with DRBIIITscan tool and replace
components as required. White smoke is typical in extreme weather
conditions.
Heater can not be switched off. Check cabin heater operation with DRBIIITscan tool and replace
components as required.
Heater does not operate. Diagnosis cabin heater control module using the DRBIIITscan tool and
the procedures listed in Vehicle Performance under Cabin Heater
Diagnosis in Group 18.
Loss of coolant (Leakage) or heater
develops smoke during combustion
operation and exhaust has an
extremely sweet smell.Inspect coolant hoses for leakage, kinks or loose hose connection.
Inspect the exhaust tube assembly for continuous flow, if OK there is an
internal heater leak and cabin heater should be inspected and
components should be replaced as required.
Loss of fuel (dripping). Check cabin heater system integration in vehicles fuel system. Check
fuel line connection for leakage. If OK there is an internal leak and
cabin heater should be inspected and replaced as required.
AIR INTAKE PIPE
REMOVAL
NOTE: The air intake tube for the supplemental
cabin heater is part of an assembly that includes
the heater cooling intake and return pipes. If the
cabin heater air intake tube requires removal or
replacement the entire cabin heater assembly will
require removal or replacement.(1) Drain the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(2) Remove clamps from the cabin heater tubes at
the lower heater port and the lower EGR connector
which are located under the hood.
(3) Remove the retaining clamp at the cabin
heater air intake muffler connection (Refer to 24 -
HEATING & AIR CONDITIONING/CABIN HEAT-
ER/INLET MUFFLER - REMOVAL).
(4) Remove the clamp at the flexible tube to steel
tube connection (Fig. 1).
RSCABIN HEATER24 - 113
CABIN HEATER (Continued)

INSTALLATION
WARNING: DO NOT OPERATE THE DIESEL SUP-
PLEMENTAL CABIN HEATER IN AN ENCLOSED
AREA SUCH AS A GARAGE THAT DOES NOT HAVE
EXHAUST VENTILATION FACILITIES. ALWAYS VENT
THE CABIN HEATER EXHAUST WHEN OPERATING
THE CABIN HEATER. ALLOW THE DIESEL SUPPLE-
MENTAL CABIN HEATER TO COOL BEFORE PER-
FORMING ANY SERVICE PROCEDURES TO THE
CABIN HEATER. VERIFY THAT ALL DIESEL SUP-
PLEMENTAL CABIN HEATER FUEL LINES ARE
SECURELY FASTENED TO THEIR RESPECTIVE
COMPONENTS BEFORE PERFORMING ANY SER-
VICE PROCEDURES TO THE CABIN HEATER. FAIL-
URE TO FOLLOW THESE INSTRUCTION MAY
RESULT IN PERSONAL INJURY OR DEATH.
NOTE: Verify that there is more than 1/8 of a tank of
fuel in the vehicle's fuel tank before performing this
procedure. Add fuel, if necessary.
(1) Install the cabin heater fuel supply line into
vehicle and fuel line retainers.
(2) Install the fuel line connection at the fuel tank
and tighten the connection securely.
(3) Install the fuel line at the dosing pump and
tighten the connection securely.
(4) Lower the vehicle.
NOTE: Failure to prime the dosing pump after drain-
ing the supplemental cabin fuel line will prevent
cabin heater activation during the first attempt to
start the cabin heater. This will also set a diagnostic
trouble code (DTC) in the cabin heater control's
memory. Do not perform the Dosing Pump Priming
procedure if an attempt was made to start the cabin
heater without priming the dosing pump first. This
will put excess fuel in the cabin heater and cause
smoke to emit from the cabin heater exhaust pipe
when cabin heater activation occurs.
(5) Connect the DRBIIItscan tool to the diagnos-
tic link connector.
(6) Turn the ignition to the ON position.
NOTE: Do not activate the dosing pump prime more
than one time. This will put excess fuel in the sup-
plemental cabin heater and cause smoke to emit
from the cabin heater exhaust pipe when cabin
heater activation occurs.
NOTE: A clicking noise heard coming from the dos-
ing pump indicates that the pump is operational.(7) With the DRBIIItscan tool in Cabin Heater,
select System Tests and Dosing Pump Prime. Allow
the dosing pump to run for the full 45 second cycle
time. When the 45 second cycle is complete, press
Page Back on the DRBIIItscan tool key pad to exit
the Dosing Pump Prime. The Dosing Pump Priming
procedure is now complete.
HEATER UNIT
REMOVAL
WARNING: DO NOT OPERATE THE DIESEL SUP-
PLEMENTAL CABIN HEATER IN AN ENCLOSED
AREA SUCH AS A GARAGE THAT DOES NOT HAVE
EXHAUST VENTILATION FACILITIES. ALWAYS VENT
THE CABIN HEATER EXHAUST WHEN OPERATING
THE CABIN HEATER. ALLOW THE DIESEL SUPPLE-
MENTAL CABIN HEATER TO COOL BEFORE PER-
FORMING ANY SERVICE PROCEDURES TO THE
CABIN HEATER. VERIFY THAT ALL DIESEL SUP-
PLEMENTAL CABIN HEATER FUEL LINES ARE
SECURELY FASTENED TO THEIR RESPECTIVE
COMPONENTS BEFORE PERFORMING ANY SER-
VICE PROCEDURES TO THE CABIN HEATER. FAIL-
URE TO FOLLOW THESE INSTRUCTION MAY
RESULT IN PERSONAL INJURY OR DEATH.
(1) Raise and support the vehicle. Take note of the
location of the flexible section of the cabin heater
exhaust tube.
(2) Drain the engine cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(3) Carefully open one hose to the underbody tube
assembly and drain the remaining coolant. A salvage
hose is a good idea to control the residual coolant, as
flow will occur from both the cabin heater and the
hose and tube assemblies.
(4) Remove the second hose from the underbody
hose and tube assembly.
(5) Loosen the hose and tube assembly from the
toe-board crossmember at two locations.
(6) Disconnect the electrical connector from the
body harness near the toe-board crossmember and
rail.
(7) Remove the wiring harness from the toe-board
crossmember (Refer to 24 - HEATING & AIR CON-
DITIONING/CABIN HEATER/HEATER UNIT -
REMOVAL).
(8) Open the fuel filler cap. Disconnect the rubber
fuel hose between the body tube assembly and the
fuel pump nipple at the body tube joint. A minimal
amount of fuel may flow from the open port.
NOTE: Utilize an approved fuel storage container to
catch any residual fuel.
24 - 118 CABIN HEATERRS
FUEL LINE (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)

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)