Heater and A/C Control Unit (DATC) Repair Procedures

Inspection

1. 1
   Self-Diagnosis Procedure

   

2. 2
   How to read the self-diagnosis code. After the display panel blinks three times every 0.5 seconds, the corresponding trouble code blinks on the set temperature display panel every 0.5 seconds and will show two digits. Codes are displayed in numeric format. Trouble code

   Display	Description of Malfunction
   00	Normal
   11	In-Car Sensor Open
   12	In-Car Sensor Short Circuit
   13	Ambient Sensor Open
   14	Ambient Air Sensor Short Circuit
   17	Evaporator Sensor Open
   18	Evaporator Sensor Short Circuit
   19	Air Temperature Door Potentiometer Open/Short - Actuator
   20	Air Temperature Door Potentiometer Malfunction - Actuator
   21	Mode Door Potentiometer Open/Short
   22	Mode Door Potentiometer Malfunction
   25	Intake Door Potentiometer Open
   26	Intake Door Potentiometer Short Circuit
   32	Air Temperature Door Potentiometer Open/Short - Passenger
   33	Air Temperature Door Potentiometer Malfunction - Passenger
   43	Anti-Fog Potentiometer Open/Short Circuit
   44	Auto Defog Potentiometer Malfunction
   45	APT CAN signal error
   46	-
   47	RPM CAN Signal Malfunction
   48	Vehicle Speed CAN Signal Malfunction
   49	Engine Coolant Temperature CAN Signal Malfunction
   50	Cluster Ionizer Generator Malfunction
   53	D/Clock Reference Signal High (above 3.75) — MTS, AVN only
   54	D/Clock Reference Signal Low (below 3.05) — MTS, AVN only
   55	Ambient Temperature Sensor Malfunction — MTS, AVN only
   56	Ambient Temperature Sensor Open/Short — MTS, AVN only

3. 3
   Trouble Code Display

   1. Continuous Operation: One DTC.

      

   2. Continuous Operation: More than two DTCs.

      

   3. STEP Operation

      A.	Normal code or one trouble code is the same as continuous operation.

      B.	More than two DTCs.

      

4. 4
   If any diagnostic trouble codes are displayed during the inspection, check the causes of the malfunction by referring to the DTC troubleshooting.
5. 5
   Fail safe.

   1. Interior Temperature Sensor: Check value 25 °C.
   2. Ambient Temperature Sensor: Check value 20 °C.
   3. Evaporator Temperature Sensor: Check value -2°C (28.4°F).
   4. Temperature control actuator (air mix potentiometer): If the temperature setting is 17°C-24°C, 5 °C, lock in the maximum cooling position. If the temperature setting is 25°C-32°C, lock in the maximum heating position.
   5. Mode Control Actuator (Direction Potentiometer): Fix the vent position when the vent mode is selected. Fix the defrost position by selecting any mode except the vent mode.
   6. Intake Control Actuator: Fix in the fresh air position when fresh air mode is selected. Fix in the recirculation position when recirculation mode is selected.
   7. Auto Defog Sensor: Check with humidity value 0%.
   8. Auto Defog Actuator: Fix Close position when Vent bi mode is selected. Fix Open position by selecting any mode except Vent bi.

Replacement

1. 1
   Disconnect the negative (-) battery terminal.
2. 2
   Using a screwdriver or remover, remove the center fascia lower panel (A).

   

3. 3
   Remove the car hose (A).
4. 4
   Disconnect the connectors of the heater and air conditioning control unit (B) from the center fascia lower panel.

   

5. 5
   Loosen the air conditioning and heater control unit mounting screws.
6. 6
   Remove the air conditioning and heater control unit (A) from the lower center panel.

   

7. 7
   Install in the reverse order of removal.