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.
Disconnect the battery in accordance with the Service information.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Dosing Pump harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Cabin Heater Assist C1 and C2 harness connectors.
Measure the resistance between the Dosing Pump Control circuit and the Ground
circuit.
Is the resistance below 10K ohms?
All
Yes
→ Repair the Dosing Pump Control circuit for a short to the Ground
circuit.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
No
→ Go To 3
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.
Disconnect the battery in accordance with the Service information.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Dosing Pump harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Cabin Heater Assist C1 harness connector.
Measure the resistance between ground and the Dosing Pump Control circuit.
Is the resistance below 10K ohms?
All
Yes
→ Repair the Dosing Pump Control circuit for a short to ground.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
No
→ Replace the DCHA Heater Module in accordance with the Service
Information.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
433
CABIN HEATER
B1820 DOSING PUMP CIRCUIT: SHORT TO GROUND —
Continued