Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. With the scan tool, read DTCs and record on the repair order.
2. Record the Environmental Data.
3. With the scan tool, erase DTCs.
4. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
5. With the scan tool, read HVAC Module DTCs.
  Did the DTC return?
  
  Yes
  - Go To 2
  No
  - Perform the TESTING FOR AN INTERMITTENT CONDITION procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
PERFORM HVAC ACTUATOR CALIBRATION TEST
1. With the scan tool, perform the HVAC Actuator Calibration Test.
  Did this DTC change from Stored to Active while performing the HVAC Actuator Calibration Test?
  
  Yes
  - Go To 3
  No
  - Perform the TESTING FOR AN INTERMITTENT CONDITION procedure Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK THE (C27) A/C COMPRESSOR CONTROL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the HVAC Module C1 harness connector.
3. Disconnect the A/C Compressor harness connector.
4. Check for continuity between ground and the (C27) A/C Compressor Control circuit at the A/C Compressor harness connector.
  Is there continuity between ground and the (C27) A/C Compressor Control circuit?
  
  Yes
  - Repair the (C27) A/C Compressor Control circuit for a short to ground.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
  No
  - Go To 4
CHECK THE VARIABLE DISPLACEMENT SOLENOID (VDC) or COMPRESSOR CONTROL VALVE FOR HIGH RESISTANCE
1. Turn the ignition off.
2. Remove the VDC Solenoid or Compressor Control Valve from the A/C Compressor. Refer to VALVE, A/C COMPRESSOR CONTROL, REMOVAL AND INSTALLATION .
3. Check the VDC Solenoid or Compressor Control Valve for high resistance.
  NOTE:
  The VDC Solenoid or Compressor Control Valve should have a resistance value of 11.0 ohms +/- 1.0 ohm.
  
  Is the VDC Solenoid or Compressor Control Valve outside of the above resistance value?
  
  Yes
  - Replace the VDC Solenoid or Compressor Control Valve. Refer to VALVE, A/C COMPRESSOR CONTROL, REMOVAL AND INSTALLATION .
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
  No
  - Go To 5
CHECK THE A/C COMPRESSOR
1. Diagnose the A/C Compressor in accordance with the Service Information. Refer to DIAGNOSIS AND TESTING .
2. With the scan tool, erase DTCs and perform the HVAC ACTUATOR CALIBRATION TEST.
  Did the DTC return?
  
  Yes
  - Go To 6
  No
  - Test complete.
  - 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 .