Page 100 of 2305

Symptom:
FLAME DETECT PRIOR TO COMBUST
When Monitored and Set Condition:
FLAME DETECT PRIOR TO COMBUST
When Monitored: During heater start up.
Set Condition: This DTC will set if the Flame Sensor's resistance is not within the
expected parameters.
POSSIBLE CAUSES
HEATER'S AIR INTAKE/EXHAUST RESTRICTED
FLAME SENSOR
TEST ACTION APPLICABILITY
1WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
WARNING: ALLOW THE HEATER ASSEMBLY TO COOL BEFORE PER-
FORMING A COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAIL-
URE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL
INJURY OR DEATH.
CAUTION: DO NOT PERFORM THIS TEST UNLESS DIRECTED HERE BY
THE HEATER PRE-TEST. ALWAYS PERFORM THE HEATER PRE-TEST
PRIOR TO PERFORMING ANY OTHER TEST FOR THE RESULT TO BE
VALID.
Turn the ignition off.
Inspect the heater's air intake pipe and exhaust pipe for restrictions and obstruc-
tions.
Is the heater's air intake pipe and exhaust pipe Ok?All
Ye s!Replace the Cabin Heater Assembly or Heater Booster Assembly
in accordance with the Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
No!Repair the heater's air intake/exhaust as necessary in accordance
with the Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
87
CABIN HEATER
Page 101 of 2305
Symptom List:
FLAME OUT
NO START
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be FLAME OUT.
When Monitored and Set Condition:
FLAME OUT
When Monitored: After heater activation and during subsequent attempts to start the
heater.
Set Condition: This DTC will set if the Flame Sensor's resistance is not within the
expected parameters.
NO START
When Monitored: After heater activation.
Set Condition: This DTC will set if the Flame Sensor's resistance is not within the
expected parameters 340 seconds after activation.
POSSIBLE CAUSES
LOW FUEL LEVEL IN VEHICLE'S FUEL TANK
HEATER'S FUEL LINE RESTRICTED/LEAKING/DAMAGED
DOSING PUMP
HEATER'S AIR INTAKE/EXHAUST RESTRICTED
CABIN HEATER ASSEMBLY OR HEATER BOOSTER ASSEMBLY
88
CABIN HEATER
Page 104 of 2305

Symptom List:
FLAME SENSOR OPEN
FLAME SENSOR SHORTED
GLOW PIN OPEN
GLOW PIN SHORTED
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be FLAME SENSOR OPEN.
When Monitored and Set Condition:
FLAME SENSOR OPEN
When Monitored: During heater activation and operation.
Set Condition: This DTC will set if the Flame Sensor's resistance is not within the
expected parameters.
FLAME SENSOR SHORTED
When Monitored: During heater activation and operation.
Set Condition: This DTC will set if the Flame Sensor's resistance is not within the
expected parameters.
GLOW PIN OPEN
When Monitored: During heater activation and operation.
Set Condition: This DTC will set if the Glow Pin's resistance is not within the expected
parameters.
GLOW PIN SHORTED
When Monitored: During heater activation and operation.
Set Condition: This DTC will set if the Glow Pin's resistance is not within the expected
parameters.
POSSIBLE CAUSES
FLAME SENSOR
91
CABIN HEATER
Page 105 of 2305
TEST ACTION APPLICABILITY
1WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
WARNING: ALLOW THE HEATER ASSEMBLY TO COOL BEFORE PER-
FORMING A COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAIL-
URE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL
INJURY OR DEATH.
CAUTION: DO NOT PERFORM THIS TEST UNLESS DIRECTED HERE BY
THE HEATER PRE-TEST. ALWAYS PERFORM THE HEATER PRE-TEST
PRIOR TO PERFORMING ANY OTHER TEST FOR THE RESULT TO BE
VALID.
Turn the ignition off.
View repairAll
Repair
Replace the Cabin Heater Assembly or Heater Booster Assembly
in accordance with the Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
92
CABIN HEATER
FLAME SENSOR OPEN ÐContinued
Page 106 of 2305

Symptom List:
HEATER IN LOCKOUT MODE
HEATER OVERHEATED
SUCCESSIVE OVERHEATING
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be HEATER IN LOCKOUT MODE.
When Monitored and Set Condition:
HEATER IN LOCKOUT MODE
When Monitored: During heater activation and operation.
Set Condition: This DTC will set if multiple attempts to start the heater have failed or if
successive overheating occurs.
HEATER OVERHEATED
When Monitored: After heater activation, when the system is in a steady state of
operation.
Set Condition: This DTC will set if the Temperature Sensor's resistance or Overheating
Sensor's resistance is not within the expected parameters (coolant temperature in the
heater module exceeds 105ÉC [221ÉF]).
SUCCESSIVE OVERHEATING
When Monitored: After heater activation, when the system is in a steady state of
operation.
Set Condition: This DTC will set if successive overheating occurs.
POSSIBLE CAUSES
CABIN HEATER ASSEMBLY OR HEATER BOOSTER ASSEMBLY
HEATER'S COOLANT HOSES RESTRICTED/LEAKING/DAMAGED
ENGINE'S COOLING SYSTEM FAULT
CABIN HEATER OR HEATER BOOSTER CONTROL UNIT
HEATER OVERHEATED/SUCCESSIVE OVERHEATING CLEARED, ADDITIONAL DTC(S)
PRESENT
93
CABIN HEATER
Page 110 of 2305

Symptom List:
OVERHEATING SENSOR OPEN
OVERHEATING SENSOR SHORTED
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be OVERHEATING SENSOR OPEN.
When Monitored and Set Condition:
OVERHEATING SENSOR OPEN
When Monitored: During heater activation and operation.
Set Condition: This DTC will set if the Overheating Sensor's resistance is not within the
expected parameters.
OVERHEATING SENSOR SHORTED
When Monitored: During heater activation and operation.
Set Condition: This DTC will set if the Overheating Sensor's resistance is not within the
expected parameters.
POSSIBLE CAUSES
OVERHEATING SENSOR
TEST ACTION APPLICABILITY
1WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
WARNING: ALLOW THE HEATER ASSEMBLY TO COOL BEFORE PER-
FORMING A COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAIL-
URE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL
INJURY OR DEATH.
CAUTION: DO NOT PERFORM THIS TEST UNLESS DIRECTED HERE BY
THE HEATER PRE-TEST. ALWAYS PERFORM THE HEATER PRE-TEST
PRIOR TO PERFORMING ANY OTHER TEST FOR THE RESULT TO BE
VALID.
Turn the ignition off.
View repairAll
Repair
Replace the Cabin Heater Assembly or Heater Booster Assembly
in accordance with the Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
97
CABIN HEATER
Page 111 of 2305

Symptom List:
TEMP SENSOR OPEN
TEMP SENSOR SHORTED
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be TEMP SENSOR OPEN.
When Monitored and Set Condition:
TEMP SENSOR OPEN
When Monitored: During heater activation and operation.
Set Condition: This DTC will set if the Temperature Sensor's resistance is not within the
expected parameters.
TEMP SENSOR SHORTED
When Monitored: During heater activation and operation.
Set Condition: This DTC will set if the Temperature Sensor's resistance is not within the
expected parameters.
POSSIBLE CAUSES
TEMPERATURE SENSOR
TEST ACTION APPLICABILITY
1WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
WARNING: ALLOW THE HEATER ASSEMBLY TO COOL BEFORE PER-
FORMING A COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAIL-
URE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL
INJURY OR DEATH.
CAUTION: DO NOT PERFORM THIS TEST UNLESS DIRECTED HERE BY
THE HEATER PRE-TEST. ALWAYS PERFORM THE HEATER PRE-TEST
PRIOR TO PERFORMING ANY OTHER TEST FOR THE RESULT TO BE
VALID.
Turn the ignition off.
View repairAll
Repair
Replace the Cabin Heater Assembly or Heater Booster Assembly
in accordance with the Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
98
CABIN HEATER
Page 113 of 2305

TEST ACTION APPLICABILITY
3WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
WARNING: ALLOW THE HEATER ASSEMBLY TO COOL BEFORE PER-
FORMING A COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAIL-
URE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL
INJURY OR DEATH.
Turn the ignition on.
With the DRBIIItin Sensors, record the Cabin Heater's or Heater Booster's
Operating Voltage.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Cabin Heater or Heater Booster harness connector.
Measure the voltage between the Fused B+ circuit and ground.
Is there more than 1.0 volt difference between the Operating Voltage and the Fused
B+ voltage?All
Ye s!Replace the Cabin Heater Assembly or Heater Booster Assembly
in accordance with the Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
No!Go To 4
100
CABIN HEATER
UNDER VOLTAGE ÐContinued