How To Troubleshoot The Heating And A/C Systems (Without Climate Control)

How to Troubleshoot the Heating and A/C Systems

How to Check for DTCs with the HDS

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

2. Connect the HDS to the 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 does not, go to the DLC circuit troubleshooting 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, do all system scan, then 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.

How to Use the Self-Diagnostic Function without the HDS

The HVAC control unit has a self-diagnostic function for the 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 OFF, the temperature control dial on Max Cool.

3. Turn the ignition switch to ON (II), and select the vent mode.

4. Press and hold the A/C button, then press the recirculation button five times within 10 seconds. Release the A/C buttons; 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 or the windshield defrost indicator will blink Diagnostic Trouble Code (DTC) 1 through 10.
- The indicator pauses 1.5 seconds, then repeats the DTC blink sequence.
- If no DTCs are found, the indicator will not blink.





Example of DTC Indication Pattern (DTC 3)






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.










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

Max Cool Position Function

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