How to Troubleshoot the Heating and A/C Systems

How to Troubleshoot the Heating and A/C Systems

Checking for DTCs

The A/C control panel has a self-diagnostic function for heating, ventilation, and air conditioning system. To run the self-diagnostic function, do the following:

1. Turn the ignition switch to LOCK (0).

2. Set the FAN CONTROL DIAL to OFF, the TEMPERATURE CONTROL DIAL on Max Cool, the MODE CONTROL DIAL to select Vent, and the REAR FAN CONTROL DIAL to OFF.

3. Turn the ignition switch to ON (II).

4. Press and hold the RECIRCULATION CONTROL button. While holding the button, press the REAR WINDOW DEFOGGER button five times within 10 seconds. The recirculation indicator blinks two times, then the self-diagnostic begins.

- If there is any problem in the system after self-diagnostic is finished, the recirculation indicator will blink Diagnostic Trouble Code (DTC) 1 through 15. If there are any problems in the evaporator temperature sensor circuit, the A/C indicator will blink DTC 7 or 8.
- If no DTC's are found, the indicator will not blink.





Example of DTC Indication Pattern (DTC 13)





Canceling the Self-diagnostic Function

- Turn the ignition switch to LOCK (0) to cancel the self-diagnostic function. After completing repair work, run the self-diagnostic function again to make sure that there are no other malfunctions.

Max Cool Position Function

When the mode control dial is in the MAX A/C position, the A/C control panel will automatically select the recirculation mode and turn the A/C on. The recirculation switch and A/C switch are disabled and cannot be turned off in this mode. If the A/C control panel fails to function as described, replace it.










In case of multiple problems, the recirculation indicator will indicate only the DTC with the least number of blinks.

How to Check for DTCs with the HDS

1. Make sure the ignition switch is in LOCK (0).

2. Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.





3. Turn the ignition switch to ON (II).

4. Make sure the HDS communicates with the vehicle and the climate control unit. If it doesn't, troubleshoot the DLC circuit Testing and Inspection.

5. Select HVAC/CLIMATE CONTROL in the BODY ELECTRICAL menu.

6. Select DTCs in the HVAC/CLIMATE CONTROL menu.

7. Check for DTCs. If any DTCs are indicated, write down the DTCs, then go to the indicated DTC troubleshooting. If no DTCs are indicated, refer to symptom troubleshooting.

NOTE:

- After troubleshooting, clear the DTCs with the HDS.
- For specific operations, refer to the user's manual that came with the HDS.