Chrysler Voyager. Manual — part 149

The temperature sensor senses the coolant tem-

perature in the heat exchanger as an electrical
resistance. This signal is sent to the control unit for
processing.

The overheat protection, controlled by the tem-

perature resistor, protects the heater against undue
operating temperatures. The overheat protection
will switch the heater off if the water temperature
exceeds 105°C (221°F).

3.10.2.6

DOSING PUMP

The dosing pump is a combined delivery, dosing,

and shut-off system for the fuel supply of the heater.
The dosing pump receives its supply of fuel from the
vehicle’s fuel tank.

3.10.3

OPERATION

3.10.3.1

VENTING THE DCHA’S EXHAUST

WARNING: DO NOT OPERATE THE DCHA IN
AN ENCLOSED AREA SUCH AS A GARAGE
THAT

DOES

NOT

HAVE

EXHAUST

VENTILATION FACILITIES. ALWAYS VENT
THE DCHA’s EXHAUST WHEN OPERATING
THE DCHA. FAILURE TO FOLLOW THESE
INSTRUCTIONS MAY RESULT IN PERSONAL
INJURY OR DEATH.

WARNING: ALLOW THE DCHA ASSEMBLY TO
COOL BEFORE PERFORMING A COMPONENT
INSPECTION/REPAIR/REPLACEMENT. FAILURE
TO

FOLLOW

THESE

INSTRUCTIONS

MAY

RESULT IN PERSONAL INJURY.

CAUTION: When using a powered exhaust
ventilation system, do not attach the exhaust
ventilation hose directly to the DCHA exhaust
pipe. Too much suction can prevent DCHA
operation.

•

When using a powered exhaust ventilation sys-
tem, affix the ventilation hose to the DCHA
exhaust pipe or to the vehicle in such a manor
that the end of the ventilation hose remains
approximately three inches away from the end of
the DCHA exhaust pipe.

•

When using a non-powered exhaust ventilation
system, affix the ventilation hose directly to the
DCHA exhaust pipe.

3.10.3.2

ACTIVATION

When the ignition is in Run, the FCM monitors

the PCI bus for the Cabin Heater Activation re-
quest. The Automatic or Manual Temperature Con-
trol initiates this request only when all conditions

for Cabin Heater activation are favorable (see be-
low). The request carries the status bit that the
FCM requires to activate its Cabin Heater Assist
Control Output. This output is a low side driver
(coming from FCM pin 15) which supplies a ground
signal to the Cabin Heater (pin 5). When the Cabin
Heater receives this ground signal input, it inter-
prets this as an activation signal. The FCM low side
driver is also capable of diagnostic sensing. The
driver will sense an open circuit when the driver is
off, and will sense a short to voltage when the driver
is on. The FCM will set DTCs for both of these types
of faults.

For vehicle’s with a Manual Temperature Control
system, the DCHA will activate only:

•

when the engine is running.

•

when the coolant temperature is below 66°C
(151°F).

•

when the fuel tank has greater than 1/8 of a tank
of fuel.

•

when the Power switch on the A/C - Heater
Control Module is on.

•

when the Blend control on the A/C - Heater
Control Module is set above 90% reheat (within 2
detents of the full heat position).

•

once per ignition cycle, when the ambient tem-
perature is below 9°C (49°F), and the vehicle
speed is above 25 km/h (15.5 mph) for two min-
utes, and the Blend control on the A/C - Heater
Control Module is set anywhere from 80% to 90%
reheat (3 to 4 detents from the full heat position).
Under this circumstance, the DCHA will remain
active for five minutes unless additional input is
supplied to the DCHA.

•

when the Front Control Module (FCM) sees the
Cabin Heater Activation request that is bussed
from the A/C - Heater Control Module.

For vehicle’s with a Automatic Temperature Control
system, the DCHA will activate only when the:

•

VIN indicates that the vehicle has a diesel engine

•

vehicle’s odometer reads more than 5 miles.

•

engine speed is above 500 rpm.

•

coolant temperature is below 66°C (151°F).

•

fuel tank has greater than 1/8 of a tank of fuel.

•

Power switch on the Automatic Temperature
Control is on.

•

Driver Temperature Control on the Automatic
Temperature Control is set above 22°C (72°F).

•

Front Control Module (FCM) sees the Cabin
Heater Activation request that is bussed from the
Automatic Temperature Control.

When the DCHA starting sequence begins, the

glow plug and the combustion air fan are activated.

23

GENERAL INFORMATION

After 30 seconds, the fuel dosing pump begins
operating and the combustion air fan operation is
suspended for 3 seconds. Subsequently, the combus-
tion air fan speed is increased in two ramps within
56 seconds to nearly full load operation. After a
stabilization phase of 15 seconds, the combustion
air fan speed is again increased in a ramp within 50
seconds to nearly full load. After reaching full load
fuel delivery, the glow plug is deactivated and the
combustion air fan operation is increased to full
load. During the subsequent 45 seconds, as well as
in normal operation, the glow plug functions as a
flame sensor to monitor the flame condition. After
all these events, the automatically controlled heat-
ing operation starts.

In case of a no flame or a flame out condition, a

restart is automatically initiated. If the no flame
condition persists, fuel delivery is stopped and the
heater enters an error lockout mode with a run-
down of the combustion air fan. This will set one or
more DTCs in the DCHA Control’s memory. If six
continuous attempts to start the heater fail due to
one or more faults in the DCHA system, the heater
enters a heater lockout mode. This will set DTC
B1813 along with any other fault(s) that the DCHA
Control identified.

3.10.3.3

HEATING

During the automatically controlled heating op-

eration, when the coolant temperature reaches
76°C (169°F), the heater will switch to a part load
operation. When the coolant temperature reaches
83°C (181°F) or if the heater runs for longer than 76
minutes the heater will switch to a control idle
period. If the coolant temperature drops to 73°C
(163°F) during a control idle period, the heater will
perform a regular starting sequence into full load
operation. A drop in coolant temperature to 66°C
(151°F) during part load operation will cause the
heater to switch to a full load operation.

3.10.3.4

DEACTIVATION

For vehicles with a Manual Temperature Control
system, the DCHA will deactivate if the:

•

engine is turned off.

•

coolant temperature reaches 83°C (181°F).

•

heater runs longer than 76 minutes (for normal
automatic controlled heating operation).

•

heater reaches 5-minute timeout period (for once
per ignition cycle operation).

•

fuel tank has less than 1/8 of a tank of fuel.

•

Power switch on the A/C - Heater Control Module
is off.

•

Blend Control on the A/C - Heater Control Mod-
ule is set below 75% reheat. 5 detents

For vehicle’s with a Automatic Temperature Control
system, the DCHA will deactivate if the:

•

engine speed drops below 500 rpm.

•

engine is turned off.

•

coolant temperature reaches 83°C (181°F).

•

heater runs longer than 76 minutes.

•

fuel tank has less than 1/8 of a tank of fuel.

•

Power switch on the Automatic Temperature
Control is off.

•

Comfort level is attained as determined by the
temperature setting on the Automatic Tempera-
ture Control.

When the heater is deactivated, the combustion

stops and a run-down sequence begins. During the
run-down sequence, the combustion air fan contin-
ues operation to cool down the heater. The fan is
automatically switched off after the run-down se-
quence is complete. The run-down time and the
combustion air fan speed depend on the heater
operating condition at the time of deactivation.
Run-down time is approximately 175 seconds when
deactivated in full load operation and approxi-
mately 100 seconds when deactivated in part load
operation.

3.10.4

DIAGNOSTICS

The DCHA is fully addressable with the DRBIII

t.

System tests include a Field Mode Test to activate
the DCHA for diagnostic testing purposes. The
DCHA Control will store up to three DTCs in its
memory. If the Controller detects a new fault in the
DCHA system, one that is not already stored in its
memory, it will clear the oldest of the three stored
DTCs, and it will store the new fault’s DTC. If the
Controller detects a reoccurrence of a stored fault, it
will overwrite that fault’s DTC with the most recent
occurrence.

For vehicles equipped with Automatic Tempera-

ture Control (ATC), the AC Cooldown Test will also
activate the DCHA for diagnostic testing purposes.
The AC Cooldown Test is actuated with the DRBIII.
The test checks A/C system performance based on
evaporator temperature sensor input. It also forces
the ATC to initiate a Cabin Heater Activation re-
quest when the vehicle is equipped with a Diesel
Cabin Heater Assist (DCHA). The air conditioning
related portion of this test will not run if ambient
temperature is below 12°C (53°F). However, the
forced Cabin Heater activation will occur even if the
air conditioning portion of this test fails to initiate
because test criteria was not met. The air condition-
ing related portion of this test will pass if the
evaporator temperature drops 6.7°C (20°F) within
two minutes of starting this test. Only air condition-
ing related messages display on the DRBIII

t after

24

GENERAL INFORMATION

running this test. These messages will clear after
paging back out of this test. Therefore, it is impor-
tant to note all of the AC Cooldown test messages
before doing so. Running the AC Cooldown test will
cause the DELAY and Snowflake VF segments on
the ATC to flash for 162 seconds. If the air condi-
tioning portion of this test fails, the DELAY and
Snowflake VF segments will continue to flash until
the vehicle is driven more than three miles.

3.11

INSTRUMENT CLUSTER

The Instrument Cluster receives and sends mes-

sages to other modules via the PCI bus circuit. The
indicator lamps will illuminate briefly for a bulb
check when the ignition is turned from off to run.
All of the gauges receive their information via the
PCI bus from the powertrain control module and
body control module.

The gauges and the LEDs are not individually

replaceable thereby requiring complete replace-
ment of the Instrument Cluster if a repair is neces-
sary. In the event that the Instrument Cluster loses
communication with other modules on the PCI bus,
the cluster will display “no bus” in the VF display.

The Trip/Reset button is used to switch the dis-

play from trip to total mileage. Holding the button
when the display is in the trip mode will reset the
trip mileage. This button is also used to put the
cluster into self-diagnostic mode. The odometer
display uses blue-green vacuum fluorescent digital
characters.

On base models, the Instrument Cluster has

three gauges: Speedometer, fuel and temperature. A
red dot moves transversely appears through open-
ings in the Instrument Cluster face (P-R-N-D-2-1)
to indicate the gear selected.

With other models, the Instrument Cluster may

also include a tachometer and use a vacuum-
fluorescent shift indicator.

The high-line Instrument Cluster features Elec-

troluminescent Illumination of the gauge faces (EL
Panel). This feature eliminates the use of bulbs for
gauge/panel lighting. In a manner similar to fluo-
rescent lights, a/c voltage from an inverter inte-
grated circuit chip is applied to the phosphorescent
material, causing it to glow. The phosphorescent
material is screen-printed onto flexible Mylar
sheets that form the gauge faces.

The odometer display and door/liftgate ajar indi-

cators turn on when a door is opened to assist both
the customer and service technician to view the
odometer without turning the ignition on.

On models with AutoStick, the display includes

an O/D OFF indicator that is illuminated when the
driver presses the Overdrive Off button on the
transaxle shifter.

For complete details of the Instrument Cluster,

refer to the RS/RG Service Manual.

3.11.1

INSTRUMENT CLUSTER SELF TEST

1. Depress and hold the Odometer Reset button.

2. Turn the ignition switch to on.

3. Release the Odometer reset button.

The Instrument Cluster will illuminate all indi-

cators and step the gauges through several calibra-
tion points. Also, the odometer will display any
stored codes that may have set.

3.11.2

MESSAGE CENTER

The Message Center is above the brow of the

Instrument Cluster. It houses the following warn-
ing indicators: Check Engine/Service Engine Soon,
High Beam, Left and Right turn signals, Security
Alarm Set, and Low Oil Pressure. On base models
equipped with the three-speed transaxle, these in-
dicators appear in the face of the cluster. The
Security Alarm set indicator is now a large red
circle symbol.

Activation of Instrument Cluster indicators is

coordinated with indicators in the message center
and EVIC where used to avoid redundancy. A re-
vised safety standard now requires that the seat
belt warning lamp in the Instrument Cluster re-
main lit if the driver seat belt is not buckled. A
headlamp out indicator is used to alert the driver
when a headlamp is not functioning.

3.12

INTERIOR LIGHTING

3.12.1

COURTESY LAMP CONTROL

The body controller has direct control over all of

the vehicle’s courtesy lamps. The body computer
will illuminate the courtesy lamps under any of the
following conditions:

1. Any door ajar and courtesy lamp switch on the

headlamp switch is not in the dome off position.

2. The courtesy lamp switch on the headlamp

switch is in the dome on position.

3. A Remote Keyless Entry unlock message is re-

ceived.

4. Driver door unlocked with key (with VTSS only).

3.12.2

ILLUMINATED ENTRY

Illuminated entry will be initiated when the cus-

tomer enters the vehicle by unlocking the doors
with the key fob, or with the key if the vehicle is
equipped with vehicle theft alarm. Upon exiting the
vehicle, if the lock button is pressed with a door
open, illuminated entry will cancel when the door

25

GENERAL INFORMATION

closes. If the doors are closed and the ignition
switch is turned on, the illuminated entry also
cancels. The illuminated entry feature will not
operate if the courtesy lamp switch is in the dome
off position.

3.12.3

INTERIOR LIGHTING BATTERY
SAVER

If any of the interior lamps are left on after the

ignition is turned off, the BCM will turn them off
after 8 minutes. To return to normal operation, the
courtesy lamps will operate after the dome lamp
switch or door ajar switch changes state. The glove
box and switched reading lamps require that the
ignition be turned to the on/acc position.

3.13

MEMORY SYSTEM

The memory system consists of power driver’s

seat, power mirror and radio presets. The Memory
Seat/Mirror Module (MSMM) is located under the
driver’s seat. It receives input from the following:
driver’s manual 8-way seat switch, driver’s seat
position sensors, PCI bus circuits, and the power
mirror sensors. The module uses these inputs to
perform the following functions: position the driv-
er’s memory seat, both exterior mirrors (during
recalls), and send/receive the memory system infor-
mation over the PCI bus.

The Memory Set Switch is wired to the Body

Control Module (BCM). A button (either #1 or #2)
pressed on the set switch causes the BCM to send a
message to the MSMM which in turn will send a
motion status message back to the BCM. If the
message from the MSMM indicates no current
motion, the BCM will send a recal message to the
module. The MSMM will set the seat, exterior
mirror and radio to the presets for the indicated
driver.

If any one of the memory controlled systems is

inoperative from its manual switch, use the sche-
matics and diagnostic information to correct the
concern. This manual addresses the memory prob-
lems only and it is assumed there is not a basic
component failure.

3.13.1

POWER SEAT

The memory power seat provides the driver with

2 position settings for the driver’s seat. Each power
seat motor is connected to the MSMM with two
motor drive circuits. Each circuit is switched be-
tween battery and ground. By being able to bi-
directionally drive the circuits, the MSMM controls
the movement of the motors based on input from
the power seat switch or from the position sensors
when performing a memory recall. Each motor
contains a potentiometer to monitor the seat posi-

tion. To monitor the position of the motor, the
MSMM sends out a 5-volt reference on the sensor
supply circuit. The sensor is grounded back to the
module on a common ground circuit. Based on the
position of the sensor, the MSMM monitors the
voltage change through the sensor on a separate
signal circuit.

The MSMM stores the input value of each of the

four seat potentiometers in memory when the sys-
tem requests a set. The driver can initiate a mem-
ory recall, using either the door mounted memory
switch or the RKE transmitter (if the remote linked
to memory feature is enabled via the EVIC). When
initiated, the MSMM adjusts the four seat sensors
(by using the motors) to match the memorized seat
position data.

For safety, the memory seat recall is disabled by

the MSMM when the vehicle is out of park position
or if the speed is not zero. Any obstruction to seat
movement over a 2-second delay will cause the seat
to stop moving in which case a stalled motor would
be detected by the MSMM and the corresponding
seat output would be deactivated. However, if the
object obstructing the seat is removed, the seat will
function normally again.

3.13.2

MEMORY MIRRORS

The driver sideview mirror contains vertical and

horizontal bi-directional drive positioning motors
and position sensors. The MSMM provides a 5-volt
reference on the signal circuit to each position
sensor. The sensors share a common ground circuit.
The MSMM monitors the position of the mirror
motors by measuring the voltage on each signal
circuit. When a memory position is set, the MSMM
monitors and stores the position of the outside
mirror. The MSMM adjusts the mirror to the appro-
priate positions when a memory recall message is
received from the RKE or is requested from the
memory set switch.

The power mirror switch during non-memory

operation operates the mirror independently of the
MSMM.

3.14

OVERHEAD CONSOLE

COMPASS/TEMPERATURE MODULE,
COMPASS/MINI-TRIP COMPUTER or
ELECTRONIC VEHICLE INFORMATION CENTER

The

Compass/Temperature

Module

(CT),

Compass/Mini-Trip Computer (CMTC) or Elec-
tronic Vehicle Information Center (EVIC) is located
in the overhead console. The CT provides the vehi-
cle operator with only outdoor temperature and the
compass heading. The CMTC or EVIC supplements
the standard vehicle instrumentation. The CMTC

26

GENERAL INFORMATION