How To Troubleshoot the Heating System

How to Retrieve a DTC


The Audio-HVAC Module has a self-diagnosis function for heating, ventilation, and air conditioning system. To run the self-diagnosis function, do the following:

1.Turn the ignition switch OFF.

2.Turn the fan switch OFF.

3.Set the temperature control dial on Max Cool, then push the mode control button to select Vent.

4.Turn the ignition switch ON (II).

5.Press and hold the recirculation control button.

6.While holding the button down, press the rear window defogger button five times within 10 seconds. The recirculation indicator blinks two times, then the self-diagnosis will begin.

  • If there is any problem in the system after self-diagnosis is finished, the recirculation indicator will blink the Diagnostic Trouble Code (DTC) 1 through 6. If there is 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 3)

Resetting the Self-diagnosis Function


Turn the ignition switch OFF to cancel the self-diagnosis function. After completing repair work, run the self-diagnosis function again to make sure that there are no other malfunctions.

Max Cool Position Function


When the mode control button is in the MAX COOL position, the Audio-HVAC Module 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 Audio-HVAC Module fails to function as described, replace the Audio-HVAC Module.