Diagnostic Procedure
HVAC SYSTEM TEST - MTC SYMPTOM CHART
| TEST | ACTION | APPLICABILITY |
|---|---|---|
| 1 | Turn the ignition on. With the DRBIII®, attempt to communicate with the Powertrain Control Module (PCM). With the DRBIII®, attempt to communicate with the Body Control Module (BCM). With the DRBIII®, attempt to communicate with the Integrated Power Module (IPM). Was the DRBIII® able to communicate with the PCM, the BCM, and the IPM? Yes --> Go To 2 No --> Refer to the COMMUNICATION category for the related symptom(s). Perform BODY VERIFICATION TEST - VER 1 . |
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| 2 | With the DRBIII®, read Powertrain Control Module (PCM) DTCs. Does the DRBIII® display any HVAC related DTCs? Yes --> Refer to the POWERTRAIN DIAGNOSTIC PROCEDURES for the related symptom(s). Perform BODY VERIFICATION TEST - VER 1 . No --> Go To 3 |
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| 3 | With the DRBIII®, read Body Control Module (BCM) DTCs. Does the DRBIII® display any DTCs? Yes --> Refer to the appropriate test for the related symptom(s). Perform BODY VERIFICATION TEST - VER 1 . No --> Go To 4 |
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| 4 | With the DRBIII®, read Integrated Power Module (IPM) DTCs. Does the DRBIII® display any DTCs? Yes --> For Integrated Power Module (IPM) DTCs related to the front blower relay circuits, refer to the HEATING & A/C category. For all other IPM DTCs, refer to the appropriate test in the related category. Perform BODY VERIFICATION TEST - VER 1 . No --> Go To 5 |
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| 5 |
NOTE:
Active DTCs must be resolved, before diagnosing stored DTCs.
NOTE:
Anytime a DTC becomes active, or a Cooldown Test fault message, Actuator Circuit Test fault message, or HVAC Door Recalibration fault message is displayed, proceed to the conclusion question.
NOTE:
If multiple DTCs are displayed, diagnose those that relate to a short circuit first. Start the engine.Press the A/C Heater Control's power switch on.Turn the mode select control to the panel position.
CAUTION:
The evaporator temperature must be above 12.7°C (55°F) and the work area ambient temperature must be above 21.1°C (70°F) to test the A/C system operation.
NOTE:
Before actuating the AC Cooldown Test, verify that the A/C compressor is not running. If the compressor is running, turn the A/C off and allow the evaporator to warm up before proceeding with the test.
NOTE:
Running the Cooldown test will cause the A/C status indicator to flash. The indicator will stop flashing if either the test passes, if any button on the control is pressed, or the ignition is cycled and the odometer shows greater than 8 miles.
NOTE:
Messages will display on the DRBIII® after running the AC Cooldown test. These messages will clear after paging back out of this test function. Therefore, it is important to note all messages before doing so. Verify that the blower motor operates correctly in all speeds. Diagnose and repair all blower related faults before proceeding with this test.Turn the blower motor control to the high speed position.With the DRBIII® in HVAC, System Tests, actuate the AC Cooldown Test. If any Cooldown Test fault messages appear, proceed to the conclusion question. Otherwise, proceed as follows:Turn the blower motor control to the low speed position.Set the passenger blend control to the full cold position.Set the driver blend control to the full cold position.Monitor the DRBIII® for active HVAC DTCs while performing the following test steps.Turn the mode select control to the defrost position, wait 30 seconds, and then turn it back to the panel position.Press the recirculation mode switch on, wait 30 seconds, and then press it off.Press the A/C mode switch on, wait 30 seconds, and then press it off.Press the rear window defogger switch on, wait 30 seconds, and then press it off.Move the passenger blend control from full cold to full hot, wait 30 seconds, and then move it back to full cold.Move the driver blend control from full cold to full hot, wait 30 seconds, and then move it back to full cold.With the DRBIII® in HVAC, System Tests, actuate the Actuator Circuit Test.With the DRBIII® in HVAC, System Tests, actuate the HVAC Door Recalibration Test.Does the DRBIII® display any active HVAC DTC(s) or System Tests fault message(s)?Yes --> Return to the Heating & A/C symptom list and choose the symptom(s).Perform BODY VERIFICATION TEST - VER 1
.No --> Go To 6 |
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| 6 | With the DRBIII®, read Powertrain Control Module (PCM) DTCs. Does the DRBIII® display any HVAC related DTCs? Yes --> Refer to the POWERTRAIN DIAGNOSTIC PROCEDURES for the related symptom(s). Perform BODY VERIFICATION TEST - VER 1 . No --> Recheck the climate control system performance. Refer to Service Information for additional information. Perform BODY VERIFICATION TEST - VER 1 . |
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