
TEST ACTION APPLICABILITY
5 If there are no possible causes remaining, view repair. All
Repair
Replace the Cabin Heater Assist in accordance with the service
information.
Perform CABIN HEATER VERIFICATION TEST - VER 1.
398
COMMUNICATION
*NO RESPONSE FROM CABIN HEATER ASSIST - DIESEL ONLY Ð
Continued

Symptom:
*NO RESPONSE FROM ECM (PCI BUS) - DIESEL ONLY
POSSIBLE CAUSES
ECM PCI NO RESPONSE
PCI BUS CIRCUIT OPEN
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
NOTE: As soon as one or more module communicates with the DRB, answer
the question.
With the DRB, enter Body then Body Computer.
With the DRB, enter Anti-Lock Brakes.
With the DRB, enter Body then Electro/Mechanical Cluster (MIC).
With the DRB, enter Passive Restraints then Airbag.
Were you able to establish communications with any of the modules?All
Ye s®Go To 2
No®Refer to symptom PCI Bus Communication Failure in the Com-
munications category.
Perform ROAD TEST VERIFICATION - VER-2.
2 With the DRB read ECM Diagnostic Trouble Codes. This is to ensure power and
grounds to the ECM are operational.
NOTE: If the DRB will not read ECM DTC's, follow the NO RESPONSE TO
ECM (SCI only) symptom path, if vehicle will start. For NO START Condi-
tions follow the no start symptom in the Starting category.
Turn the ignition off.
Disconnect the ECM harness connectors.
Use Scope input cable CH7058, Cable to Probe adapter CH7062, and the red and
black test probes.
Connect the scope input cable to the channel one connector on the DRB. Attach the
red and black leads and the cable to probe adapter to the scope input cable.
With the DRBIIItselect Pep Module Tools.
Select lab scope.
Select Live Data.
Select 12 volt square wave.
Press F2 for Scope.
Press F2 and use the down arrow to set voltage range to 20 volts. Press F2 again
when complete.
Connect the Black lead to ground. Connect the Red lead to the PCI Bus circuit in the
ECM connector.
Turn the ignition on.
Observe the voltage display on the DRB Lab Scope.
Does the voltage pulse from 0 to approximately 7.5 volts?All
Ye s®Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No®Repair the PCI Bus circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
401
COMMUNICATION

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
5 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the DRB from the DLC.
Measure the resistance of the SCI Transmit circuit between the ECM connector and
the DLC.
Is the resistance below 5.0 ohms?All
Ye s®Go To 6
No®Repair the SCI Transmit circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
6 If there are no possible causes remaining, view repair. All
Repair
Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
403
COMMUNICATION
*NO RESPONSE FROM ECM (SCI ONLY) - DIESEL ONLY ÐContinued

Symptom:
*ANY PCI BUS INDICATOR INOPERATIVE
POSSIBLE CAUSES
NO RESPONSE - PCI BUS
NO RESPONSE - INSTRUMENT CLUSTER
NO RESPONSE - ECM / PCM
INDICATOR INOPERATIVE
INSTRUMENT CLUSTER
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, select J1850 Module Scan.
Does the DRBIIItdisplay MIC PRESENT on the BUS?All
Ye s®Go To 2
No®Refer to the COMMUNICATION category and perform the ap-
propriate symptom.
Perform BODY VERIFICATION TEST - VER 1.
2 Turn the ignition on.
With the DRBIIIt, Select Body, MIC, the MODULE DISPLAY.
Does the DRBIIItdisplay NO RESPONSE from MIC?All
Ye s®Refer to the symptom list for problems related to *NO RE-
SPONSE FROM THE INSTRUMENT CLUSTER.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 3
3 Turn the ignition on.
With the DRBIIIt, select Body, MIC, SYSTEM TESTS, PCM MONITOR.
Does the DRBIIItdisplay PCM INACTIVE on the BUS?All
Ye s®Refer to the symptom list for problems related to *NO RE-
SPONSE FROM THE POWERTRAIN CONTROL MODULE
(Gas) / or *NO RESPONSE FROM THE ENGINE CONTROL
MODULE (Diesel)
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 4
4NOTE: Diagnose and repair any PCM (gas) or ECM (diesel) DTCs before
proceeding with this test.
Perform the Instrument Cluster diagnostic Self Test.
Observe the indicator in question during the Self Test.
Did the indicator illuminate?All
Ye s®Refer to the appropriate Servic Information category to diagnose
the related system.
Perform BODY VERIFICATION TEST - VER 1.
No®Replace the Instrument Cluster in accordance with the Service
Information.
Perform BODY VERIFICATION TEST - VER 1.
616
INSTRUMENT CLUSTER

Symptom:
OTIS MODULE MESSAGE MISMATCH (DIESEL)
When Monitored and Set Condition:
OTIS MODULE MESSAGE MISMATCH (DIESEL)
When Monitored: With the ignition on.
Set Condition: FCM has learned EC Mirror but the vehicle is Not equipped with EC
Mirror.
POSSIBLE CAUSES
INTERMITTENT CONDITION
CMTC/EVIC COMMUNICATION
CMTC/EVIC MODULE
FRONT CONTROL MODULE
TEST ACTION APPLICABILITY
1NOTE: All communication DTC(s) that may have set along with this DTC
must diagnosed before continuing.
NOTE: If the DTC EC Mirror Day/Night Line Fault is present in the EVIC
along with this DTC, diagnose the EC Mirror Day/Night Line Fault first
before continuing.
With the DRBIIIt, erase the DTC.
Cycle the ignition on and off several times, leaving the ignition on for at least 15
seconds.
With the DRBIIIt, read DTCs.
Did the DTC OTIS Module Message Mismatch reset?All
Ye s®Go To 2
No®Go To 4
2 Turn the ignition on.
With the DRBIIIt, attempt to communicate with the CMTC/EVIC Module.
Can communication be established with the CMTC/EVIC Module?All
Ye s®Go To 3
No®Refer to the Communication Category and perform the appropri-
ate symptom.
Perform BODY VERIFICATION TEST - VER 1.
717
OVERHEAD CONSOLE

TEST ACTION APPLICABILITY
3 Turn the ignition off.
Install a substitute CMTC/EVIC Module in place of the original module.
With the DRBIIIt, erase DTCs.
Turn the ignition on.
Cycle the ignition on and off, leaving the ignition in the on position for at least 15
seconds each time.
With the DRBIIIt, read DTCs.
Did the DTC reset?All
Ye s®Replace the Front Control Module.
Perform BODY VERIFICATION TEST - VER 1.
No®Replace the CMTC/EVIC Module.
Perform BODY VERIFICATION TEST - VER 1.
4WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s®Repair as necessary
Perform BODY VERIFICATION TEST - VER 1.
No®Test Complete.
718
OVERHEAD CONSOLE
OTIS MODULE MESSAGE MISMATCH (DIESEL) ÐContinued

CABIN HEATER VERIFICATION TEST - VER 1 APPLICABILITY
1. WARNING: DO NOT OPERATE THE DCHA IN AN ENCLOSED AREA SUCH AS A
GARAGE THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE DCHA's EXHAUST WHEN OPERATING THE DCHA. FAILURE TO FOL-
LOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY OR DEATH.
2. WARNING: ALLOW THE DCHA ASSEMBLY TO COOL BEFORE PERFORMING A
COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAILURE TO FOLLOW
THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.
3. NOTE: The DCHA Control will store up to three DTCs in its memory.
4. 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.
5. 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 occurrence.
6. Verify that the vehicle's battery is fully charged.
7. Verify that there is more than 1/8 of a tank of fuel in the vehicle's fuel tank. Add fuel, if
necessary.
8. Verify that all DCHA coolant hoses and fuel lines are securely fastened to their respective
components.
9. Disconnect all jumper wires and reconnect all previously disconnected components and
connectors.
10. If a heater installation/cooling system service was performed, purge the coolant circuit of
air in accordance with the Service Information.
11. Turn the ignition on.
12. Set the Blend Control to the max cool position.
13. Ensure that all accessories are turned off.
14. If a fuel system service requiring fuel to drain out of the DCHA fuel line was performed,
prime the DCHA Dosing Pump in accordance with the Service Information.
15. With the DRBIIIt, record and erase all DTCs from the Diesel Cabin Heater Assist (DCHA)
Control and the Front Control Module (FCM). Cycle the ignition off then on.
16. Start the engine.
17. Allow the engine to idle.
18. Turn the A/C - Heater Control Module's Power switch on.
19. Turn the Blower switch to the high speed position.
20. 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.
21. 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.
22. NOTE: While performing the Diesel Cabin Heater Test, inspect the coolant and
fuel connections for leakage.
23. With the DRBIIItin HVAC, Systems Tests, select Diesel Cabin Heater Test and press #1.
24. Set the Blend Control to the max heat position. Allow the Diesel Cabin Heater Test to run
for five minutes. Upon completion of the test, proceed as follows:
25. Set the Blend Control to the max cool position.
26. Press #2 on the DRBIIItkeyboard.
27. Turn the Blower switch off.
28. Turn the A/C - Heater Control Module's Power switch off.
29. Turn the ignition off, wait 5 seconds, then turn the ignition on.
30. Using the DRBIIIt, read the Cabin Heater and Active FCM DTCs.
Are any DTC's present or is the original condition still present?All
Ye s®Repair is not complete, refer to the appropriate symptom.
No®Repair is complete.
991
VERIFICATION TESTS
Verification Tests ÐContinued