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:
B1802 POWER SUPPLY OUT OF RANGE: LOW VOLTAGE THRESH-
OLD
When Monitored and Set Condition:
B1802 POWER SUPPLY OUT OF RANGE: LOW VOLTAGE THRESHOLD
When Monitored: With the engine running.
Set Condition: This DTC will set if the DCHA's power supply voltage drops below 10.0
volts for longer than 20 seconds.
POSSIBLE CAUSES
FIELD MODE TEST RUN WITH THE ENGINE OFF
VEHICLE'S BATTERY SYSTEM
VEHICLE'S CHARGING SYSTEM NOT OPERATING PROPERLY
DCHA CONTROL UNIT FAULT
FUSED B+ CIRCUIT HIGH RESISTANCE
DCHA CONTROL UNIT 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.
Was the Field Mode Test run with the engine off?All
Ye s®Rerun the Field Mode Test exactly as it is described in Test 4 of
the Cabin Heater Pre-Test. If DTC B1802 resets, Go To Test #2 of
this symptom. Otherwise, perform other diagnosis and testing as
necessary.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
No®Go To 2
304
CABIN HEATER
Symptom:
B1813 HEATER IN LOCKOUT MODE
When Monitored and Set Condition:
B1813 HEATER IN LOCKOUT MODE
When Monitored: During DCHA activation.
Set Condition: This DTC will set if six continuous attempts to start heater operation fail
due to one or more faults in the DCHA system.
POSSIBLE CAUSES
B1813 AND ADDITIONAL DTC(S) PRESENT
B1813 RESET, NO ADDITIONAL DTC(S) PRESENT
B1813 CLEARED, ADDITIONAL DTC(S) PRESENT
STORED DCHA DTC(S) TEST COMPLETE
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.
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.
Set the Blend Control to the max heat position.
Remove Cabin Heater Fuse #15 from the IPM for a minimum of five seconds, then
reinstall the fuse. The DCHA may attempt to start.
Turn the Blower switch off and turn the A/C - Heater Control Module's Power switch
off.
Turn the engine off.
View repairAll
Repair
Go To 2
313
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.
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:
HEADLAMP SWITCH MISMATCH
When Monitored and Set Condition:
HEADLAMP SWITCH MISMATCH
When Monitored: Ignition ON
Set Condition: Headlamp switch is in Auto mode and the vehicle is not EC Mirror
equipped.
POSSIBLE CAUSES
VERIFY AUTO HEADLAMP SWITCH
INTERMITTENT WIRING AND CONNECTORS
BODY CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, record and erase DTC's.
Turn the headlamps to the Auto position.
With the DRBIIIt, read DTCs.
Does the DRBIIItdisplay HEADLAMP SWITCH MISMATCH?All
Ye s®Go To 2
No®Go To 4
2 Visually identify the Headlamp Switch type.
Does the Headlamp Switch Contain an Auto Headlamp position?All
Ye s®Replace the Auto Headlamp Switch with a non Auto Headlamp
Switch.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 3
3 If there are no possible causes remaining, view repair. All
Repair
Replace and program the Body Control Module in accordance with
the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
4 The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this
circuit.
Wiggle the wiring while checking for shorts and open circuits.
Were there any problems found?All
Ye s®Repair as necessary.
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
449
EXTERIOR LIGHTING
Symptom List:
A/C FAULT (STORED) - MANUAL A/C
BACKLIGHT DIMMING RX FAILURE (STORED) - MANUAL A/C
BLEND OVERCURRENT (STORED) - MANUAL A/C
CHECKSUM FAILURE (STORED) - MANUAL A/C
EVAPORATOR TEMPERATURE SENSOR CIRCUIT OPEN
(STORED) - MANUAL A/C
EVAPORATOR TEMPERATURE SENSOR CIRCUIT SHORT
(STORED) - MANUAL A/C
LOOPBACK FAILURE (STORED) - MANUAL A/C
LOOPBACK TEST FAILURE (STORED) - MANUAL A/C
MODE OVERCURRENT (STORED) - MANUAL A/C
NO BCM MESSAGE RECEIVED (STORED) - MANUAL A/C
NO PCM MESSAGE RECEIVED (STORED) - MANUAL A/C
PCM COMMUNICATION FAILURE (STORED) - MANUAL A/C
POWER FAULT (STORED) - MANUAL A/C
REAR BLEND OVERCURRENT (STORED) - MANUAL A/C
REAR BLEND POT CIRCUIT OPEN (STORED) - MANUAL A/C
REAR BLEND POT CIRCUIT SHORT (STORED) - MANUAL A/C
REAR DEFOG FAILURE (STORED) - MANUAL A/C
REAR MODE OVERCURRENT (STORED) - MANUAL A/C
RECIRC OVERCURRENT (STORED) - MANUAL A/C
RECIRCULATION FAULT (STORED) - MANUAL A/C
TX FAILURE (STORED) - MANUAL A/C
UNKNOWN FAULT DETECTED (STORED) - MANUAL A/C
VEHICLE ODOMETER FAILURE (STORED) - MANUAL A/C
ZONE OVERCURRENT (STORED) - MANUAL A/C
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be A/C FAULT (STORED) - MANUAL
A/C.
When Monitored and Set Condition:
A/C FAULT (STORED) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the A/C switch stays closed for 10 minutes.
BACKLIGHT DIMMING RX FAILURE (STORED) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: If the A/C - Heater Control Module does not receive the dimming function
message from the BCM for more than 5 seconds, then the A/C - Heater Control Module
LEDs will default to full brightness and the DTC will set.
514
HEATING & A/C
BLEND OVERCURRENT (STORED) - MANUAL A/C
When Monitored: When actuator movement is requested.
Set Condition: All (Blend, Mode, Recirc, and Zone) Overcurrent DTCs will set if the A/C
- Heater Control Module detects an excessive current draw on the Common Door Drive
circuit(s).
CHECKSUM FAILURE (STORED) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the calibrated check sum does not match the stored
value.
EVAPORATOR TEMPERATURE SENSOR CIRCUIT OPEN (STORED) - MANUAL
A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the Evaporator Temperature Sensor/sensor circuit is
open.
EVAPORATOR TEMPERATURE SENSOR CIRCUIT SHORT (STORED) - MAN-
UAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the Evaporator Temperature Sensor/sensor circuit is
shorted low.
LOOPBACK FAILURE (STORED) - MANUAL A/C
When Monitored: When the A/C - Heater Control Module executes an internal loopback
test.
Set Condition: If the A/C - Heater Control Module fails to send a message, or none of the
expected messages arrive for 5 seconds, an internal loopback test is executed. If the
internal loopback test fails, the DTC will set.
LOOPBACK TEST FAILURE (STORED) - MANUAL A/C
When Monitored: When the A/C - Heater Control Module executes an internal loopback
test.
Set Condition: If the A/C - Heater Control Module fails to send a message, or none of the
expected messages arrive for 5 seconds, an internal loopback test is executed. If the
internal loopback test fails, the DTC will set.
MODE OVERCURRENT (STORED) - MANUAL A/C
When Monitored: When actuator movement is requested.
Set Condition: All (Blend, Mode, Recirc, and Zone) Overcurrent DTCs will set if the A/C
- Heater Control Module detects an excessive current draw on the Common Door Drive
circuit(s).
515
HEATING & A/C
A/C FAULT (STORED) - MANUAL A/C ÐContinued
NO BCM MESSAGE RECEIVED (STORED) - MANUAL A/C
When Monitored: With the igntion on.
Set Condition: If the A/C - Heater Control Module does not receive the dimming function
message from the BCM for more than 5 seconds, then the A/C - Heater Control Module
LEDs will default to full brightness and the DTC will set.
NO PCM MESSAGE RECEIVED (STORED) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the A/C - Heater Control Module does not see any
messages from the PCM for more than 5 seconds.
PCM COMMUNICATION FAILURE (STORED) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the A/C - Heater Control Module does not receive the
Fuel message from the PCM for more than 5 seconds.
POWER FAULT (STORED) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the Power switch stays closed for 10 minutes.
REAR BLEND OVERCURRENT (STORED) - MANUAL A/C
When Monitored: When actuator movement is requested.
Set Condition: All (Blend, Mode, Recirc, and Zone) Overcurrent DTCs will set if the A/C
- Heater Control Module detects an excessive current draw on the Common Door Drive
circuit(s).
REAR BLEND POT CIRCUIT OPEN (STORED) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the Rear Blower Rear Control Switch, Rear Blend
Potentiometer/circuit is open.
REAR BLEND POT CIRCUIT SHORT (STORED) - MANUAL A/C
When Monitored: When the ignition is on.
Set Condition: This DTC will set if the Rear Blower Rear Control Switch, Rear Blend
Potentiometer/5 Volt Supply/Rear Temperature Feedback Signal circuit is shorted low or
high.
REAR DEFOG FAILURE (STORED) - MANUAL A/C
When Monitored: With the ignition on.
Set Condition: This DTC will set if the Rear Window Defogger switch stays closed for 10
minutes.
516
HEATING & A/C
A/C FAULT (STORED) - MANUAL A/C ÐContinued