Chrysler Town, Dodge Caravan. Manual - part 768
Symptom List:
B1821 COMBUSTION AIR FAN CIRCUIT: OPEN
B1821 COMBUSTION AIR FAN CIRCUIT: SHORT TO GROUND
Test Note:
All symptoms listed above are diagnosed using the same tests.
The title for the tests will be B1821 COMBUSTION AIR FAN
CIRCUIT: OPEN.
When Monitored and Set Condition:
B1821 COMBUSTION AIR FAN CIRCUIT: OPEN
When Monitored:
After DCHA activation, when the system is in a steady state of
operation.
Set Condition:
This DTC will set if the DCHA Control detects no-load voltage on the
Combustion Air Fan circuit output pin.
B1821 COMBUSTION AIR FAN CIRCUIT: SHORT TO GROUND
When Monitored:
After DCHA activation, when the system is in a steady state of
operation.
Set Condition:
This DTC will set if the DCHA Control detects a high current draw on the
Combustion Air Fan circuit output pin.
POSSIBLE CAUSES
COMBUSTION AIR FAN/DCHA CONTROL UNIT FAULT
TEST
ACTION
APPLICABILITY
1
WARNING: 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.
NOTE: If present, diagnose and repair DTC B1801 Flame Out before diag-
nosing this DTC.
Turn the ignition off.
View repair
All
Repair
Replace the DCHA Heater Module in accordance with the Service
Information.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
308
CABIN HEATER