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.
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 B1811 Heater Overheated and
any other conditions relating to overheating before diagnosing this DTC.
Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Dosing Pump harness connector.
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, 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.
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 DTCs.
Turn the Blower switch off and turn the A/C - Heater Control Module's Power switch
off.
Turn the engine off.
Is DTC B1820 Dosing Pump Circuit: Short to Ground present?All
Ye s®Go To 2
No®Replace the Dosing Pump in accordance with the Service Infor-
mation.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
319
CABIN HEATER
B1820 DOSING PUMP CIRCUIT: SHORT TO GROUND ÐContinued
TEST ACTION APPLICABILITY
3WARNING: 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.
Turn the ignition on.
With the DRBIIIt, check for FCM and HVAC DTCs.
Does the DRBIIItdisplay any FCM or HVAC DTCs?All
Ye s®For FCM DTCs, return to the symptom list and choose the
symptom(s). Also, refer to Intelligent Power Module for related
symptom(s). For HVAC DTCs, refer to Heater & A/C for related
symptom(s).
Perform CABIN HEATER VERIFICATION TEST - VER 1.
No®Go To 4
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.
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 Diesel Cabin Heater 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 HVAC, Systems Tests, select Diesel Cabin Heater Test and press
#1.
With the DRBIIItin HVAC, Systems Tests, Diesel Cabin Heater Test, read the Cabin
Heater Status.
Does the Status display: On?All
Ye s®Replace the FCM in accordance with the Service Information.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
No®Replace the A/C - Heater Control Module in accordance with the
Service Information.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
333
CABIN HEATER
*CABIN HEATER INOPERABLE FROM A/C - HEATER MODULE Ð
Continued
Symptom:
*NO RESPONSE FROM ECM (SCI ONLY) - DIESEL ONLY
POSSIBLE CAUSES
CHECK ECM POWERS AND GROUNDS
CABIN HEATER ASSIST
SCI TRANSMIT CIRCUIT SHORTED TO VOLTAGE
SCI TRANSMIT CIRCUIT SHORTED TO GROUND
SCI TRANSMIT CIRCUIT OPEN
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1 Perform the symptom Checking ECM Power and Ground Circuits in the Driveability
category.
Did the vehicle pass this test?All
Ye s®Go To 2
No®Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
2 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the DRB from the DLC.
Measure the resistance between ground and the SCI Transmit circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 3
No®Go To 4
3 Turn the ignition off.
Disconnect the Cabin Heater Assist C1 harness connector.
Measure the resistance between ground and the SCI Transmit circuit.
Is the resistance below 5.0 ohms?All
Ye s®Repair the SCI Transmit circuit for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
No®Replace the Cabin Heater Assist in accordance with the service
information.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Disconnect the DRB from the DLC.
Disconnect the ECM harness connectors.
Disconnect the Cabin Heater Assist C1 harness connector.
Turn the ignition on.
Measure the voltage of the SCI Transmit circuit at the DLC connector (cav 7).
Is the voltage above 1.0 volt?All
Ye s®Repair the SCI Transmit circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 5
402
COMMUNICATION
TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the TCM harness connector.
Remove the starter relay from the IPM.
Using a 12-volt test light connected to ground, probe the Ignition Switch Output
(Start) circuit.
Note: The light must illuminate brightly, if it does not light, or lights dimly,
the circuit must be repaired. If there is any doubt, compare the brightness
when testing the circuit, to the brightness when connected directly to the
battery positive post.
Observe the test light while momentarily turning the ignition switch to the Start
position.
Is the test light illuminated?All
Ye s®Go To 4
No®Repair the Ignition Switch Output (Start) circuit for an open.
Refer to the wiring diagrams located in the Service Information.
Perform 41TE TRANSMISSION VERIFICATION TEST - VER 1.
Note: Reinstall the original Starter Relay.
4 Turn the ignition off.
Disconnect the TCM harness connector.
Using a 12-volt test light connected to ground, probe the Fused B(+) circuit.
Note: The light must illuminate brightly, if it does not light, or lights dimly,
the circuit must be repaired. If there is any doubt, compare the brightness
when testing the circuit, to the brightness when connected directly to the
battery positive post.
Is the test light illuminated?All
Ye s®Go To 5
No®Check IPM fuse #15 for an open. If OK, repair the Fused B(+)
circuit for an open. Refer to the wiring diagrams located in the
Service Information.
Perform 41TE TRANSMISSION VERIFICATION TEST - VER 1.
5 Turn the ignition off.
Disconnect the TCM harness connector.
Using a 12-volt test light connected to 12-volts, probe each ground circuit in the TCM
connector.
NOTE: The light must illuminate brightly, if it does not light, or lights dimly,
the circuit must be repaired. If there is any doubt, compare the brightness
when testing the circuit, to the brightness when connected directly to the
battery negative post.
Is the light illuminated at all ground circuits?All
Ye s®Go To 6
No®Repair the Ground circuit(s) for an open. Check the main ground
connection to engine block and/or chassis. Refer to the wiring
diagrams located in the Service Information.
Perform 41TE TRANSMISSION VERIFICATION TEST - VER 1.
421
COMMUNICATION
*NO RESPONSE FROM TRANSMISSION CONTROL MODULE ÐContinued
POSSIBLE CAUSES
CHECK FOR ACTIVE HVAC DTCS, & COOLDOWN TEST & DOOR RECALIBRATION MESSAGES
STORED CODE(S) TEST COMPLETE
TEST ACTION APPLICABILITY
1NOTE: Active codes must be resolved before diagnosing stored codes.
NOTE: Anytime a code becomes active during this test, proceed to the
conclusion question.
Turn the ignition on.
With the DRBIIIt, record and erase stored HVAC DTC's.
Cycle the ignition switch.
Start the engine.
Monitor the DRBIIItfor active HVAC DTCs while performing the following test
steps.
Manually press the A/C - Heater Control power switch on.
Turn the front blower motor control switch knob to the low position.
If equipped, turn the rear blower motor control switch knob to the low position.
Set the passenger blend control switch to the full cold position.
If equipped, set the zone/driver blend control switch to the full cold position.
Turn the mode select switch knob to the panel position.
Manually press the recirculation mode switch on, wait 30 seconds then press it off.
Manually press the A/C mode switch on, wait 30 seconds then press it off.
Manually press the rear window defogger switch on, wait 30 seconds then press it off.
Manually sweep the passenger blend control switch from full cold to full hot then
back to full cold.
If equipped, manually sweep the zone/driver blend control switch from full cold to full
hot then back to full cold.
Manually sweep the front blower motor control switch knob through all positions.
If equipped, manually sweep the rear blower motor control switch knob through all
positions.
If equipped, turn the rear blower motor control switch knob to the rear position.
If equipped, on the Rear Blower Rear Control, manually sweep the rear blower motor
control switch knob through all positions.
If equipped, on the Rear Blower Rear Control, manually sweep the rear blend/mode
control switch knob from full cold to full hot then back to full cold.
With the DRBIIIt, actuate the AC Cooldown Test.
With the DRBIIIt, actuate the HVAC Door Recalibration Test.
Place the vehicle on a hoist, and raise the wheels off the floor.
WARNING: Be sure to keep hands and feet clear of rotating wheels. Keep
clear of the engine's moving parts
Start the engine. Place the transmission in drive. Brake off.
Does the DRBIIItdisplay any active HVAC DTC(s), Cooldown Test or Door Recali-
bration message(s)?All
Ye s®Return to the symptom list and choose the symptom(s).
Perform BODY VERIFICATION TEST - VER 1.
No®No problem found at this time.
Perform BODY VERIFICATION TEST - VER 1.
518
HEATING & A/C
A/C FAULT (STORED) - MANUAL A/C ÐContinued
Symptom:
COOLDOWN TEST SET UP FAULT - MANUAL A/C
When Monitored and Set Condition:
COOLDOWN TEST SET UP FAULT - MANUAL A/C
When Monitored: When executing the Cooldown Test.
Set Condition: This message will be displayed if the front blower is not operating at high
speed when executing the Cooldown Test.
POSSIBLE CAUSES
HVAC DTC(S) PRESENT
TEST SET UP CONDITIONS NOT MET
FRONT BLOWER/RELATED CIRCUITS
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, read HVAC DTCs.
Does the DRBIIItdisplay any HVAC DTCs?All
Ye s®Return to the symptom list and choose the symptoms(s). After the
repair is complete, with the DRBIIIt, erase the DTC(s). Cycle the
ignition switch. With the DRBIIIt, actuate the Cooldown Test.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 2
2 Was the Front Blower Front Control switch set to high speed when the Cooldown Test
was actuated?All
Ye s®Check the front blower motor and related circuits for front blower
operation problems. Repair as necessary. After repair is complete,
with the DRBIIIt, actuate the Cooldown Test.
Perform BODY VERIFICATION TEST - VER 1.
No®Start the engine. Set the Front Blower Front Control switch to
high speed. With the DRBIIIt, actuate the Cooldown Test.
Perform BODY VERIFICATION TEST - VER 1.
534
HEATING & A/C
Symptom:
COOLDOWN TEST TOO COLD TO START - MANUAL A/C
When Monitored and Set Condition:
COOLDOWN TEST TOO COLD TO START - MANUAL A/C
When Monitored: When executing the Cooldown Test.
Set Condition: This message will be displayed if the A/C - Heater Control Module sees
evaporator temperature below 12.7ÉC (55ÉF) when executing the Cooldown Test.
POSSIBLE CAUSES
EVAPORATOR TEMPERATURE TOO LOW
HVAC DTC(S) PRESENT
CHECK THE PCM/ECM FOR DTCS
EVAPORATOR TEMPERATURE SENSOR
SENSOR GROUND CIRCUIT HIGH RESISTANCE
EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT HIGH RESISTANCE
A/C - HEATER CONTROL MODULE
TEST ACTION APPLICABILITY
1CAUTION: The work area ambient temperature must be above 15.6ÉC (60ÉF)
to test A/C system operation.
Start the engine.
Turn the A/C off.
Turn the Blower on high. Allow the blower to run for 5 minutes to ensure that the
Evaporator Temperature Sensor temperature is above 12.7ÉC (55ÉF).
With the DRBIIIt, actuate the Cooldown Test.
Does the DRBIIItdisplay: Cooldown Test Too Cold To Start?All
Ye s®Go To 2
No®Perform additional testing as necessary.
Perform BODY VERIFICATION TEST - VER 1.
2CAUTION: The work area ambient temperature must be above 15.6ÉC (60ÉF)
to test A/C system operation.
Turn the ignition on.
With the DRBIIIt, read HVAC DTCs.
Does the DRBIIItdisplay any HVAC DTCs?All
Ye s®Return to the symptom list and choose the symptom(s). After the
repair is complete, with the DRBIIIt, erase the DTC(s). Cycle the
ignition switch. With the DRBIIIt, actuate the Cooldown Test.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 3
535
HEATING & A/C
Symptom:
EL PANEL SHORT
POSSIBLE CAUSES
CHECK EXTERIOR ILLUMINATION
CHECK OPERATION OF ALL GAUGES
VERIFY CONCERN
PANEL LAMP DRIVER CIRCUIT SHORT TO GROUND
PANEL LAMP DRIVER OPEN CIRCUIT
OPEN GROUND CIRCUIT
BCM PANEL LAMP DRIVER CIRCUIT INTERNAL FAILURE
INSTRUMENT CLUSTER PANEL LAMPS DRIVER INTERNAL FAILURE
TEST ACTION APPLICABILITY
1 Ignition on, engine not running.
Turn the Headlamp Switch to the ON position.
Monitor the Instrument Cluster gauges for illumination.
Are any Instrument Cluster gauges illuminated?All
Ye s®Go To 3
No®Go To 2
2 Ignition on, engine not running.
Turn the Headlamp Switch to the ON position.
Monitor the Instrument Cluster gauges for illumination.
Are all of the Instrument Cluster gauges illuminated?All
Ye s®Go To 3
No®Replace the Instrument Cluster.
Perform BODY VERIFICATION TEST - VER 1.
3 Ignition on, engine not running.
Turn the headlamp switch to the ON position.
Monitor the Headlamps for illumination.
Are the Headlamps illuminated?All
Ye s®Go To 4
No®Refer to EXTERIOR ILLUMINATION for the related symp-
tom(s).
Perform BODY VERIFICATION TEST - VER 1.
4 Ignition on, engine not running.
With the DRBIIIt, erase DTCs.
Cycle the ignition switch from OFF to ON.
Wait 1 to 2 minutes for the system to cycle.
With the DRBIIIt, read DTCs.
Did the DTC reset?All
Ye s®Go To 5
No®Perform the Instrument Cluster Self-Test and verify the concern.
Perform BODY VERIFICATION TEST - VER 1.
565
INSTRUMENT CLUSTER