Diagnostic Test

READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN
1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
2. With the scan tool, run a Vehicle Scan Report, or record the Environmental Data.
3. With the scan tool, erase DTCs.
4. Turn the ignition off for at least 10.0 seconds.
5. Turn the ignition on.
6. Using the recorded Environmental Data and the When Monitored Conditions above, operate the vehicle in the conditions that set the DTC.
7. With the scan tool, read DTCs.
Did the DTC return?

Yes
- Go To 2
No
- Perform the TESTING FOR AN INTERMITTENT CONDITION diagnostic procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
ISOLATE AND CHECK THE (C56) FRONT BLOWER PWM CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit. Check the disconnected connectors and related harnesses for damage, corrosion, and loose fitting terminals.
3. Turn the ignition on, engine not running.
4. Measure voltage on the circuit being tested.
Is there and voltage present?

Yes
- Repair the circuit for a short to voltage.
- Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
No
- Go To 3
REPLACE THE BLOWER MOTOR POWER MODULE AND CHECK FOR THE DTC TO RETURN
1. Replace the Blower Motor Power Module in accordance with the Service Information. Refer to MODULE, POWER, BLOWER MOTOR, REMOVAL AND INSTALLATION .
2. Connect the component and ECU harness connectors.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Using the Environmental Data or When Monitored information above, operate the vehicle within the conditions that set the DTC.
6. With the scan tool, read DTCs.
Did the DTC return?

Yes
- Go To 4
No
- Replacing the Blower Motor Power Module corrected the condition.
- Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
CHECK RELATED HARNESS CONNECTIONS
1. Disconnect all HVAC Module harness connectors.
2. Disconnect all related in-line harness connections (if equipped).
3. Disconnect the related component harness connectors.
4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Perform a terminal drag test on each connector terminal to verify proper terminal tension.
  Repair any conditions that are found.
5. Reconnect all HVAC Module harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. With the scan tool, erase DTCs.
9. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
10. With the scan tool, read HVAC Module DTCs.
  Did the DTC return?
  
  Yes
  - Replace the HVAC Module in accordance with the Service information. Refer to MODULE, HVAC, REMOVAL AND INSTALLATION .
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
  No
  - The wiring or poor connection problem has been repaired.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .