engine coolant CHRYSLER VOYAGER 2001 Service Manual

3.9.2.11 HVAC DIAGNOSTICS
The A/C ± Heater Control Module is fully addres-
sable with the DRBIIIt. Two of the Control Mod-
ule's diagnostic capabilities that the DRBIIItwill
actuate include the A/C Cooldown Test to test A/C
system performance and the HVAC Door Recalibra-
tion Test to determine actuator travel span. After
performing either test, the Control Module will
display one or more messages on the DRBIIIt
screen. The message will indicate either that the
HVAC system passed the test or that there is a fault
currently active in the HVAC system. The DRBIIIt
can also extract active and stored Diagnostic Trou-
ble Codes (DTCs) from the control module. Active
DTCs are faults that currently exit in the HVAC
system. Active DTCs cannot be erased until the
condition causing the code is repaired. Stored DTCs
are faults that occurred in the HVAC system since
the control module received the last ªclear diagnos-
tic infoº message.
3.10 CABIN HEATER
NOTE: The Cabin Heater, also known as the
Diesel Cabin Heater Assist (DCHA), will be
referred to as the DCHA throughout most of
the General Information and the Diagnostic
Procedures in this manual.
3.10.1 GENERAL SAFETY INFORMATION
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 COM-
PONENT INSPECTION/REPAIR/REPLACE-
MENT. FAILURE TO FOLLOW THESE
INSTRUCTIONS MAY RESULT IN PERSONAL
INJURY.
WARNING: ALWAYS DISCONNECT THE
VEHICLE'S BATTERY PRIOR TO PER-
FORMING ANY TYPE OF WORK ON THE
DCHA. FAILURE TO FOLLOW THESE
INSTRUCTIONS MAY RESULT IN PERSONAL
INJURY OR DEATH.WARNING: NEVER ATTEMPT TO REPAIR THE
DCHA HEATER MODULE OR ANY OF ITS
INTERNAL COMPONENTS. ALWAYS PER-
FORM DCHA COMPONENT REPLACEMENT
IN ACCORDANCE WITH THE SERVICE
INFORMATION. FAILURE TO FOLLOW
THESE INSTRUCTIONS MAY RESULT IN
PERSONAL INJURY OR DEATH.
CAUTION: Do not actuate the DCHA Field
Mode Test with the engine off. Failure to
follow these instructions may result in
internal damage to the DCHA Heater Module.
CAUTION: Always Perform The Cabin Heater
Pre-Test Prior To Performing Any Other Cabin
Heater Test For The Test Result To Be Valid.
NOTE: Do not disconnect the vehicle's
battery or the DCHA's main power-supply
while the DCHA is in operation or in
run-down mode. Failure to follow these
instructions may result in excess emissions
from the DCHA Heater Module.
NOTE: Failure to prime the Dosing Pump
after draining the DCHA fuel line will prevent
DCHA heater activation during the first
attempt to start the heater. This will also set a
Diagnostic Trouble Code (DTC) in the DCHA
Control's memory. Do not perform the Dosing
Pump Priming Procedure if an attempt was
made to start the DCHA without priming the
Dosing Pump first. This will put excess fuel
in the DCHA Heater Module and cause smoke
to emit from the DCHA exhaust pipe when
heater activation occurs.
NOTE: Waxed fuel can obstruct the fuel line
and reduce flow. Check for the appropriate
winter grade fuel and replace as necessary.
3.10.2 COMPONENT DESCRIPTION AND
OPERATION
3.10.2.1 DCHA ASSEMBLY
The DCHA is a supplemental heater designed to
pre-heat the engine's coolant in order to supply the
vehicle's occupants with heat prior to the engine
reaching operating temperature. The DCHA assem-
bly mounts underneath the vehicle on the left side
floor pan near the front door opening. The DCHA
assembly connects to the vehicle's heater hoses and
has a fuel supply line that connects to the vehicle's
fuel tank.
19
GENERAL INFORMATION

The DCHA assembly consists of a:
²combustion air fan assembly
²burner housing
²burner insert
²control unit/heat exchanger
²combustion chamber
²dosing pump
3.10.2.2 COMBUSTION AIR FAN
The combustion air fan assembly includes the:
²combustion air fan
²combustion air fan inlet
²fuel supply inlet
The combustion air fan delivers the air required
for combustion from the combustion air inlet to the
burner insert.
3.10.2.3 BURNER HOUSING
The burner housing includes the:
²coolant inlet
²coolant outlet
²exhaust outlet
The burner housing accommodates the burner
insert and is combined with the control unit/heat
exchanger as an assembly.
3.10.2.4 BURNER INSERT
The burner insert includes the:
²combustion pipe fuel cross section
²glow plug/flame sensor
Inside the burner insert fuel is distributed across
the combustion pipe fuel cross section. Combustion
of the fuel/air mixture takes place within the com-
bustion pipe to heat the exchanger. The glow plug/
flame sensor located in the burner insert ignites the
fuel/air mixture during heater start up. After heater
start up, the glow plug/flame sensor operates in the
flame sensor function. The glow plug/flame sensor
designed as an electrical resistor is located in the
burner insert opposite the flame side.
3.10.2.5 CONTROL UNIT/HEAT
EXCHANGER
The control unit/heat exchanger includes the:
²control unit
²temperature sensor
²overheat protection
²heat exchanger
²connector terminal
The control unit controls and monitors combus-
tion operation. The control unit is ventilated bymeans of a ventilation hose routed from the com-
bustion air collector compartment of the burner.
The heat exchanger transfers the heat generated by
combustion to the coolant circuit. The control unit/
heat exchanger and the burner housing are an
assembly and must not be disassembled.
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 105ÉC (221ÉF).
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 ACTIVATION
When the ignition is in Run, the FCM monitors
the PCI bus for the Cabin Heater Activation re-
quest. The A/C ± Heater Control Module initiates
this request only when all conditions for Cabin
Heater activation are favorable (see below). 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 interprets this as an activa-
tion 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.
The DCHA will activate only when the:
²engine is running.
²coolant temperature is below 66ÉC (151ÉF).
²fuel tank has greater than 1/8 of a tank of fuel.
²Power switch on the A/C ± Heater Control Module
is on.
²Blend Control on the A/C ± Heater Control Mod-
ule is set above 95% reheat.
²Front Control Module (FCM) sees the Cabin
Heater Activation request that is bussed from the
A/C ± Heater Control Module.
When the DCHA starting sequence begins, the
glow plug and the combustion air fan are activated.
After 30 seconds, the fuel dosing pump begins oper-
20
GENERAL INFORMATION

ating and the combustion air fan operation is sus-
pended for 3 seconds. Subsequently, the combustion
air fan speed is increased in two ramps within 56
seconds to nearly full load operation. After a stabi-
lization 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.
3.10.3.2 HEATING
During the automatically controlled heating op-
eration, when the coolant temperature reaches
72ÉC (162ÉF), the heater will switch to a part load
operation. When the coolant temperature reaches
75ÉC (167ÉF) 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 71ÉC
(160ÉF) during a control idle period, the heater will
perform a regular starting sequence into full load
operation. A drop in coolant temperature to 65ÉC
(149ÉF) during part load operation will cause the
heater to switch to a full load operation.
3.10.3.3 DEACTIVATION
The DCHA will deactivate if the:
²engine is turned off.
²coolant temperature reaches 75ÉC (167ÉF).
²heater runs longer than 76 minutes.
²fuel tank has less than 1/8 of a tank of fuel.
²Power switch on the A/C ± Heater Control Module
is off.
²Blend Control on the A/C ± Heater Control Mod-
ule is set below 75% reheat.
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 thecombustion 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 DRBIIIt.
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.
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 ªno busº 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 in self-diagnostic mode. The odometer dis-
play uses blue-green vacuum fluorescent digital
characters.
On base vehicles, the Instrument Cluster has
three gauges: Speedometer, Fuel and Engine Cool-
ant Temperature. A red dot moves transversely
through openings in the Instrument Cluster face
(P-R-N-D-2-1) to indicate the gear selected.
With all other models, the Instrument Cluster
also includes a Tachometer and uses a vacuum-
fluorescent shift indicator.
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.
21
GENERAL INFORMATION

TEST ACTION APPLICABILITY
4WARNING: DO NOT OPERATE THE DCHA IN AN ENCLOSED AREA SUCH
AS A GARAGE THAT DOES NOT HAVE EXHAUST VENTILATION FACILI-
TIES. 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 PERFORM-
ING A COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAILURE TO
FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.
NOTE: The DCHA Control will store up to three DTCs in its memory.
NOTE: If the DCHA Control detects a new fault in the DCHA system, one
that is not already stored in its memory, the DCHA Control will clear the
oldest of the three stored DTCs, and it will store the new fault's DTC.
NOTE: If the DCHA control detects a reoccurrence of a stored fault, the
DCHA control will overwrite that fault's DTC with the most recent occur-
rence.
Turn the ignition on.
Set the Blend Control to the max cool position.
Turn the A/C - Heater Control Module's Power switch off.
With the DRBIIIt, record and erase Cabin Heater and FCM DTCs.
Start the engine.
Allow the engine to idle.
Turn the A/C - Heater Control Module's Power switch on.
Turn the Blower switch to the high speed position.
CAUTION: Do not activate the DCHA Field Mode Test with the engine off.
Failure to follow these instructions may result in internal damage to the
DCHA Heater Module.
NOTE: Do not disconnect the vehicle's battery or the DCHA's main power
supply while the DCHA is in operation or in run-down mode. Failure to
follow these instructions may result in excess emissions from the DCHA
during heater operation.
With the DRBIIItin Cabin Heater, Systems Tests, select Field Mode and press Enter.
Set the Blend Control to the max heat position. Upon completion of the Field Mode
Test, proceed as follows:
With the DRBIIIt, read Cabin Heater and Active FCM DTCs.
Turn the Blower switch off and turn the A/C - Heater Control Module's Power switch
off.
Turn the engine off.
Are any DTCs present?All
Ye s®Return to the symptom list and choose the DTC(s). Diagnose and
repair all FCM faults prior to diagnosing DCHA faults. If DTC
B1813 Heater In Lockout Mode reset with other DTC(s), reset the
heater before diagnosing the other DTC(s).
Perform CABIN HEATER VERIFICATION TEST - VER 1.
No®Go To 5
5 Is the symptom Cabin Heater inoperable from the A/C - Heater Module? All
Ye s®Refer to symptom *Cabin Heater Inoperable From A/C - Heater
Module in the Cabin Heater category.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
No®Let DCHA cool. Inspect fuel line, intake & exhaust, & coolant
hoses for restrictions, obstructions, loose clamps, leakage, etc.
Check connectors. Clean & repair as necessary. Refer to Service
Manual for additional symptom based diagnosis, if necessary.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
298
CABIN HEATER
CABIN HEATER PRE-TEST ÐContinued

Symptom:
B1811 HEATER OVERHEATED
When Monitored and Set Condition:
B1811 HEATER OVERHEATED
When Monitored: After DCHA activation, when the system is in a steady state of
operation.
Set Condition: This DTC will set if the Coolant Temperature Sensor resistance is not
within the expected parameters (coolant temperature in the Heater Module exceeds 125ÉC
[257ÉF]).
POSSIBLE CAUSES
DCHA HEATER MODULE FAULT
DCHA COOLANT HOSES RESTRICTED/LEAKING/DAMAGED
ENGINE'S COOLING SYSTEM FAULT
DCHA CONTROL UNIT FAULT
B1811 CLEARED, ADDITIONAL DTC(S) PRESENT
TEST ACTION APPLICABILITY
1WARNING: DO NOT OPERATE THE DCHA IN AN ENCLOSED AREA SUCH
AS A GARAGE THAT DOES NOT HAVE EXHAUST VENTILATION FACILI-
TIES. 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 PERFORM-
ING A COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAILURE TO
FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.
CAUTION: DO NOT PERFORM THIS TEST UNLESS DIRECTED HERE BY
THE CABIN HEATER PRE-TEST. ALWAYS PERFORM THE CABIN HEATER
PRE-TEST PRIOR TO PERFORMING ANY OTHER CABIN HEATER TEST
FOR THE RESULT TO BE VALID.
Turn the ignition off.
NOTE: If there is an internal leak in the Heater Module, a continuous loud
chunking or grinding noise may have been heard coming from the DCHA
assembly during the Field Mode test.
Check for engine coolant continuously flowing out of the DCHA exhaust pipe.
Is engine coolant coming out of the DCHA exhaust pipe?All
Ye s®Replace the DCHA Heater Module in accordance with the Service
Information.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
No®Go To 2
309
CABIN HEATER

TEST ACTION APPLICABILITY
2WARNING: DO NOT OPERATE THE DCHA IN AN ENCLOSED AREA SUCH
AS A GARAGE THAT DOES NOT HAVE EXHAUST VENTILATION FACILI-
TIES. 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 PERFORM-
ING A COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAILURE TO
FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.
Turn the ignition off.
Inspect the DCHA coolant hoses for restrictions, leakage, and damage.
Are the DCHA coolant hoses Ok?All
Ye s®Go To 3
No®Repair the DCHA coolant hoses as necessary in accordance with
the Service Information.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
3WARNING: DO NOT OPERATE THE DCHA IN AN ENCLOSED AREA SUCH
AS A GARAGE THAT DOES NOT HAVE EXHAUST VENTILATION FACILI-
TIES. ALWAYS VENT THE DCHA's EXHAUST WHEN OPERATING THE
DCHA. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN
PERSONAL INJURY OR DEATH.
Check that the engine's cooling system is operating properly in accordance with the
Service Information.
Is the engine's cooling system operating properly?All
Ye s®Go To 4
No®Repair the engine's cooling system in accordance with the Service
Information.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
4WARNING: DO NOT OPERATE THE DCHA IN AN ENCLOSED AREA SUCH
AS A GARAGE THAT DOES NOT HAVE EXHAUST VENTILATION FACILI-
TIES. ALWAYS VENT THE DCHA's EXHAUST WHEN OPERATING THE
DCHA. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN
PERSONAL INJURY OR DEATH.
Start the engine.
Allow the engine to reach normal operating temperature.
Turn the engine off.
Allow the engine's coolant to cool down to a temperature of 50ÉC (122ÉF).
Start the engine.
Allow the engine to reach normal operating temperature.
Turn the engine off.
View repairAll
Repair
Go To 5
310
CABIN HEATER
B1811 HEATER OVERHEATED ÐContinued

TEST ACTION APPLICABILITY
2WARNING: DO NOT OPERATE THE DCHA IN AN ENCLOSED AREA SUCH
AS A GARAGE THAT DOES NOT HAVE EXHAUST VENTILATION FACILI-
TIES. ALWAYS VENT THE DCHA's EXHAUST WHEN OPERATING THE
DCHA. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN
PERSONAL INJURY OR DEATH.
NOTE: The DCHA Control will store up to three DTCs in its memory.
NOTE: If the DCHA Control detects a new fault in the DCHA system, one
that is not already stored in its memory, the DCHA Control will clear the
oldest of the three stored DTCs, and it will store the new fault's DTC.
NOTE: If the DCHA control detects a reoccurrence of a stored fault, the
DCHA control will overwrite that fault's DTC with the most recent occur-
rence.
Turn the ignition on.
Set the Blend Control to the max cool position.
Turn the A/C - Heater Control Module's Power switch off.
With the DRBIIIt, record and erase Cabin Heater DTCs.
Start the engine.
Allow the engine to idle.
Turn the A/C - Heater Control Module's Power switch on.
Turn the Blower switch to the high speed position.
CAUTION: Do not activate the DCHA Field Mode Test with the engine off.
Failure to follow these instructions may result in internal damage to the
DCHA Heater Module.
With the DRBIIItin Cabin Heater, Systems Tests, select Field Mode and press Enter.
Set the Blend Control to the max heat position. Upon completion of the Field Mode
Test, proceed as follows:
With the DRBIIIt, read Cabin Heater and Active FCM DTCs.
Turn the Blower switch off and turn the A/C - Heater Control Module's Power switch
off.
Turn the engine off.
Are any DTCs present?All
Yes, B1813 & Other DTC(s) Present
Return to the symptom list and choose the additional DTC(s) first,
then diagnose B1813.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
Yes, B1813 Reset with No Other DTC(s)
Allow DCHA to cool. Inspect DCHA intake & exhaust pipes for
restrictions & obstructions. Repair as necessary. After repair,
repeat Test 2 of this procedure. If intake & exhaust pipes are Ok,
replace DCHA Heater Module in accordance with Service Info.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
Yes, B1813 Cleared, Other DTC(s) Present
Return to the symptom list and choose the DTC(s).
Perform CABIN HEATER VERIFICATION TEST - VER 1.
No®Allow DCHA to cool. Inspect fuel line & coolant hoses for restric-
tions, obstructions, loose clamps, leakage, etc. Repair as neces-
sary. Check connectors. Clean & repair as necessary. Refer to
Service Manual for additional symptom diagnosis, if necessary.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
314
CABIN HEATER
B1813 HEATER IN LOCKOUT MODE ÐContinued

Symptom:
*CABIN HEATER INOPERABLE FROM A/C - HEATER MODULE
POSSIBLE CAUSES
DCHA ACTIVATION CRITERIA NOT MET
ATTEMPT TO COMMUNICATE WITH THE FCM AND THE HVAC MODULE
FCM OR HAVC DTCS PRESENT
VERIFY DCHA IS INOPERABLE FROM A/C - HEATER MODULE
A/C - HEATER CONTROL MODULE FAULT
TEST ACTION APPLICABILITY
1WARNING: DO NOT OPERATE THE DCHA IN AN ENCLOSED AREA SUCH
AS A GARAGE THAT DOES NOT HAVE EXHAUST VENTILATION FACILI-
TIES. ALWAYS VENT THE DCHA's EXHAUST WHEN OPERATING THE
DCHA. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN
PERSONAL INJURY OR DEATH.
CAUTION: DO NOT PERFORM THIS TEST UNLESS DIRECTED HERE BY
THE CABIN HEATER PRE-TEST. ALWAYS PERFORM THE CABIN HEATER
PRE-TEST PRIOR TO PERFORMING ANY OTHER CABIN HEATER TEST
FOR THE RESULT TO BE VALID.
Verify that all of the following criteria was met during the attempt to activate the
DCHA from the A/C - Heater Control Module.
The engine was running.
The engine coolant temperature was below 66ÉC (151ÉF).
The vehicle's fuel tank had more than 1/8 of a tank of fuel.
The A/C - Heater Control Module's Power switch was on.
The Blend Control was set above 95% reheat.
Was all criteria met during the attempt to activate the DCHA from the A/C - Heater
Control Module?All
Ye s®Go To 2
No®Attempt to activate the DCHA when all of the operating criteria
are met.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
2WARNING: DO NOT OPERATE THE DCHA IN AN ENCLOSED AREA SUCH
AS A GARAGE THAT DOES NOT HAVE EXHAUST VENTILATION FACILI-
TIES. ALWAYS VENT THE DCHA's EXHAUST WHEN OPERATING THE
DCHA. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN
PERSONAL INJURY OR DEATH.
Turn the ignition on.
With the DRBIIIt, attempt to communicate with the FCM and the HVAC Module.
Was the DRBIIItable to communicate with the FCM and the HVAC Module?All
Ye s®Go To 3
No®Refer to Communication for the related symptom(s)
Perform CABIN HEATER VERIFICATION TEST - VER 1.
332
CABIN HEATER

CABIN HEATER VERIFICATION TEST - VER 1 APPLICABILITY
1. 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 FOL-
LOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY OR DEATH.
2. WARNING: ALLOW THE DCHA ASSEMBLY TO COOL BEFORE PERFORMING A
COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAILURE TO FOLLOW
THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.
3. NOTE: The DCHA Control will store up to three DTCs in its memory.
4. NOTE: If the DCHA Control detects a new fault in the DCHA system, one that is not
already stored in its memory, the DCHA Control will clear the oldest of the three
stored DTCs, and it will store the new fault's DTC.
5. NOTE: If the DCHA control detects a reoccurrence of a stored fault, the DCHA
control will overwrite that fault's DTC with the most recent occurrence.
6. Verify that the vehicle's battery is fully charged.
7. Verify that there is more than 1/8 of a tank of fuel in the vehicle's fuel tank. Add fuel, if
necessary.
8. Verify that all DCHA coolant hoses and fuel lines are securely fastened to their respective
components.
9. Disconnect all jumper wires and reconnect all previously disconnected components and
connectors.
10. If a heater installation/cooling system service was performed, purge the coolant circuit of
air in accordance with the Service Information.
11. Turn the ignition on.
12. Set the Blend Control to the max cool position.
13. Ensure that all accessories are turned off.
14. If a fuel system service requiring fuel to drain out of the DCHA fuel line was performed,
prime the DCHA Dosing Pump in accordance with the Service Information.
15. With the DRBIIIt, record and erase all DTCs from the Diesel Cabin Heater Assist (DCHA)
Control and the Front Control Module (FCM). Cycle the ignition off then on.
16. Start the engine.
17. Allow the engine to idle.
18. Turn the A/C - Heater Control Module's Power switch on.
19. Turn the Blower switch to the high speed position.
20. CAUTION: Do not activate the Diesel Cabin Heater Test with the engine off.
Failure to follow these instructions may result in internal damage to the DCHA
Heater Module.
21. NOTE: Do not disconnect the vehicle's battery or the DCHA's main power supply
while the DCHA is in operation or in run-down mode. Failure to follow these
instructions may result in excess emissions from the DCHA during heater operation.
22. NOTE: While performing the Diesel Cabin Heater Test, inspect the coolant and
fuel connections for leakage.
23. With the DRBIIItin HVAC, Systems Tests, select Diesel Cabin Heater Test and press #1.
24. Set the Blend Control to the max heat position. Allow the Diesel Cabin Heater Test to run
for five minutes. Upon completion of the test, proceed as follows:
25. Set the Blend Control to the max cool position.
26. Press #2 on the DRBIIItkeyboard.
27. Turn the Blower switch off.
28. Turn the A/C - Heater Control Module's Power switch off.
29. Turn the ignition off, wait 5 seconds, then turn the ignition on.
30. Using the DRBIIIt, read the Cabin Heater and Active FCM DTCs.
Are any DTC's present or is the original condition still present?All
Ye s®Repair is not complete, refer to the appropriate symptom.
No®Repair is complete.
991
VERIFICATION TESTS
Verification Tests ÐContinued

ENGINE CONTROL MODULE C1 (DIESEL) - BLACK 81 WAYCAV CIRCUIT FUNCTION
1 Z130 14BK/BR GROUND
2 Z131 14BK/DG GROUND
3 K20 14BR/GY GENERATOR FIELD CONTROL
4 K342 14BR/WT ECM/PCM RELAY OUTPUT
5 K342 14BR/WT ECM/PCM RELAY OUTPUT
6- -
7 D25 20WT/VT PCI BUS
8 K944 20BK/GY CAMSHAFT POSITION SENSOR SHIELD GROUND
9 K44 20DB/GY CAMSHAFT POSITION SENSOR SIGNAL
10 - -
11 K37 20DB/YL BOOST PRESSURE SENSOR SIGNAL
12 K55 20DB/OR MASS AIR FLOW SENSOR SIGNAL
13 K78 20GY FUEL PRESSURE SENSOR SIGNAL
14 - -
15 K22 20OR/DB ACCELERATOR PEDAL POSITION SENSOR SIGNAL
16 K80 20DB/TN FUEL PRESSURE SENSOR GROUND
17 - -
18 - -
19 N1 20DB/OR FUEL HEATER RELAY OUTPUT
20 Z138 20BK/OR GROUND
21 K900 20DB/DG SENSOR GROUND
22 F202 20PK/GY IGNITION SWITCH OUTPUT (RUN-START)
23 F851 20LB/PK SENSOR REFERENCE VOLTAGE B
24 K3 20BR/OR CRANKSHAFT POSITION SENSOR SIGNAL NO. 1
25 - -
26 - -
27 - -
28 - -
29 - -
30 G6 20VT/GY ENGINE OIL PRESSURE SENSOR SIGNAL
31 F853 20LG/PK WATER IN FUEL SENSOR SIGNAL
32 K25 20BR/TN BATTERY TEMPERATURE SENSOR SIGNAL
33 - -
34 K167 20BR/YL ACCELERATOR PEDAL POSITION SENSOR GROUND
35 K853 20DB/BR ACCELERATOR PEDAL POSITION SENSOR 5 VOLT SUPPLY
36 C18 20LB/BR A/C PRESSURE SENSOR SIGNAL
37 K89 20DB/WT ENGINE OIL TEMPERATURE SENSOR SIGNAL
38 V37 20VT/TN SPEED CONTROL SWITCH SIGNAL
39 - -
40 K2 20TN/BK ENGINE COOLANT TEMPERATURE SENSOR SIGNAL
41 K21 20DB/LG INTAKE AIR TEMPERATURE SENSOR SIGNAL
42 Z122 18WT GROUND (DRAIN)
43 K24 20BR/LB CRANKSHAFT POSITION SENSOR SIGNAL NO. 2
44 - -
45 - -
46 - -
47 L50 20WT/TN PRIMARY BRAKE SWITCH SIGNAL
48 B29 20DG/WT SECONDARY BRAKE SWITCH SIGNAL
49 T751 20YL IGNITION SWITCH OUTPUT (START)
50 F855 20PK/YL SENSOR REFERENCE VOLTAGE A
C
O
N
N
E
C
T
O
R
P
I
N
O
U
T
S
1039
CONNECTOR PINOUTS