Without Scan Tool

How to Use the Self-diagnostic Function without the HDS

The HVAC control unit 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 OFF.
2. Set the fan control dial OFF, the temperature control dial on Max Cool.
3. Turn the ignition switch 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 will blink Diagnostic Trouble Code (DTC) 1 through 10.
- If no DTCs are found, the indicator will not blink.

Cancelling the Self-diagnostic Function

5. Turn the ignition switch OFF 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 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 switch and A/C switch are disabled and cannot be turned off in this mode. If the HVAC control unit fails to function as described, replace it.