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 HVACR 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 .
CHECK THE CONDITION OF THE REAR AIR TEMPERATURE SENSOR CONNECTOR AND TERMINALS
1. Turn the ignition off.
2. Check the temperature sensor and harness connector and terminals for improper installation, damage, and corrosion.
  Were any problems found?
  
  Yes
  - Repair the connector and terminals as necessary.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
  No
  - Go To 3
CHECK THE (C168) REAR PANEL TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. The ignition must be off when checking a circuit for continuity to ground.
2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and the component harness connectors containing the circuit being tested. Note: Use the appropriate SYSTEM 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. Connect the negative lead of the Digital Volt-Ohm Meter (DVOM) to a known good ground.
4. With the positive lead of the DVOM, probe the circuit being tested at the component harness connector and check for continuity between the circuit and ground.
  NOTE:
  When back-probing a circuit at a harness connector, always use an appropriate back probing tool to prevent damage to the connector terminals.
  
  Is there continuity between ground and the circuit being tested?
  
  Yes
  - Repair the circuit for a short to ground. Use the appropriate SYSTEM WIRING DIAGRAM as a guide to trace the circuit and identify any in-line connectors that may help isolate the location of the short.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
  No
  - Go To 4
CHECK THE (C168) REAR PANEL TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT AT THE ECU HARNESS CONNECTOR
1. The ignition must be off when performing a resistance check to find a short between circuits.
2. Isolate the circuit by disconnecting the ECU and the component harness connectors containing the circuit being tested. Note: Use the appropriate SYSTEM 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. Connect one lead of the DVOM to the circuit being tested at the ECU harness connector.
4. With the other lead of the DVOM probe all other circuits at the ECU harness connector.
  NOTE:
  When back-probing a circuit at a harness connector, always use an appropriate back probing tool to prevent damage to the connector terminals.
  
  Is there continuity between the circuit being tested and any other circuit?
  
  Yes
  - Repair the circuit for a short to another circuit. Use the appropriate SYSTEM WIRING DIAGRAM as a guide to trace the circuits and look for any in-line connectors to help isolate the location of the short.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
  No
  - Go To 5
REPLACE THE REAR AIR TEMPERATURE SENSOR AND CHECK FOR THE DTC TO RETURN
1. Replace the Rear Air Temperature Sensor in accordance with the Service Information. Refer to SENSOR, TEMPERATURE, AIR OUTLET, REMOVAL AND INSTALLATION or SENSOR, TEMPERATURE, AIR OUTLET, REMOVAL AND INSTALLATION .
2. Connect the Rear Air Temperature Sensor, ECU, and any other disconnected harness connectors.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Using the Environmental Data and When Monitored conditions, operate the vehicle within the conditions that set the DTC.
6. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Go To 6
  No
  - Replacing the Rear Air Temperature Sensor corrected the condition.
  - Perform the HVAC VERIFICATION TEST. Refer to HVAC VERIFICATION TEST .
CHECK RELATED HARNESS CONNECTIONS
1. Disconnect all HVACR 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 HVACR 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 HVACR Module DTCs.
  Did the DTC return?
  
  Yes
  - Replace the HVACR 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 .