TEST
ACTION
APPLICABILITY
2
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 CAN 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 CAN RESULT IN PERSONAL INJURY
OR DEATH.
Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Cabin Heater Assist C1 harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Dosing Pump harness connector.
Measure the resistance of the Dosing Pump Control circuit between the Dosing Pump
harness connector and the Cabin Heater Assist C1 harness connector.
Is the resistance below 5.0 ohms?
All
Yes
→ Go To 3
No
→ Repair the Dosing Pump Control circuit for an open.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
3
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 CAN 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 CAN RESULT IN PERSONAL INJURY
OR DEATH.
Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Cabin Heater Assist C2 harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Dosing Pump harness connector.
Measure the resistance of the Ground circuit between the Dosing Pump harness
connector and the Cabin Heater Assist C2 harness connector.
Is the resistance below 5.0 ohms?
All
Yes
→ Go To 4
No
→ Repair the Ground circuit for an open.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
429
CABIN HEATER
B1820 DOSING PUMP CIRCUIT: OPEN OR SHORT TO BATTERY —
Continued