How to Troubleshoot the Climate Control System

How to Troubleshoot the Climate Control System

How to Retrieve a DTC

NOTE: LHD type is shown, RHD type is symmetrical.

The climate control unit has a self-diagnostic function. To run the self-diagnostic function, do the following:

1.	Set the temperature control button to Max Cool (Lo) with the ignition switch ON (II).

2.

Press and hold the OFF button. While holding the OFF button, press the rear window defogger button five times within 10 seconds. Release the OFF button and the self-diagnostic will begin. NOTE: The blower motor can be run at any speed regardless of what the panel is displaying.   OFF BUTTONREAR WINDOW DEFOGGER BUTTONTEMPERATURE INDICATOR

If there is any problem in the system, the temperature indicator will light up the segment (A through N) corresponding to the error. The temperature indicator will then alternate every second between displaying ‘‘88'' (all segments lit) and the error code segment (A through N). To determine the meaning of the DTC, refer to the DTC Troubleshooting Index.

If there are no problems detected, the segments will not illuminate.

 

Canceling the Self-diagnostic Function

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

Checking DTCs

To retrieve the DTC, you must run the self-diagnostic function. In the case of multiple problems, the respective indicator segments will come on. If indicator segments A, C, E, G, I and L come on at the same time, there may be an open in the common ground wire.

 

DTC (Temperature Indicator segment)	Detection Item
A	An open in the in-car temperature sensor circuit
B	A short in the in-car temperature sensor circuit
C	An open in the outside air temperature sensor circuit
D	A short in the outside air temperature sensor circuit
E	An open in the sunlight sensor circuit
F	A short in the sunlight sensor circuit
G	An open in the evaporator temperature sensor circuit
H	A short in the evaporator temperature sensor circuit
I	An open in the air mix control motor circuit
J	A short in the air mix control motor circuit
K	A problem in the air mix control linkage, door, or motor
L	An open or short in the mode control motor circuit
M	A problem in the mode control linkage, doors, or motor
N	A problem in the blower motor circuit

Displaying Sensor Inputs at the Climate Control Unit

The climate control unit has a mode that displays sensor inputs it receives. This mode shows you what the climate control unit is receiving from each of the sensors, one at a time, and it can help you determine if a sensor is faulty.

Check these items before using the sensor input display mode

1.	Turn the ignition switch ON (II), and check the recirculation door function; press the recirculation button to switch from FRESH to RECIRC. The air volume and sound should change slightly.

2.

Set the temperature control knob to the desired test temperature. When selecting the test temperatures, note these items: ‘‘Lo'' temperature setting will default to MAX COOL, VENT, and RECIRC. ‘‘Hi'' temperature setting will default to MAX HOT, FLOOR, and FRESH. 16 through 32°C settings will use the automatic climate control logic.

3.	Turn the ignition switch OFF.

To run the sensor input display mode, follow these steps

1.	Turn the ignition switch OFF.

2.	Press and hold both the AUTO and recirculation buttons, then start the engine.

3.	After the engine starts, release the buttons. The display panel control unit will flash the sensor number and then the value for that sensor. Record the value displayed.

4.

To advance to the next sensor, press the rear window defogger button. Sensor  Item  Displayed Value  1  In-car Temperature Sensor  °C  2  Ambient Temperature  °C  3  Solar Radiation Sensor Value: Dark = 00, Flashlight = 04, Cloudy =10, Sunny =65  Kcal/m2·h  4  Engine coolant Temperature  °C  5  Evaporator Outlet Air Temperature  °C  6  Air Mix Opening (Low value indicates cooler air distribution, higher value indicates warmer air distribution)  % of opening  7  Vent Temperature Air Out (TAO)  °C  NOTE: The sensor values will be displayed in degrees Celsius (°C) or an alphanumeric code. Use the chart to convert the value to degrees Fahrenheit (°F). If the sensor value displays ‘‘Er'' this indicates there is an open or short in the circuit or sensor. Check for DTCs using the HDS, or refer to checking DTCs by DTC indication to check for DTCs. If necessary, compare the sensor input display to an alike, known-good vehicle under the same test conditions. If the sensor is out of the normal range, refer to the sensor test, or substitute the sensor with a known-good, and recheck.

5.

To cancel the sensor input display mode, press the AUTO button, or turn the ignition off. Celsius to Fahrenheit Conversion Table °C  °F  °C  °F  °C  °F  °C  °F  °C  °F  0  32  10  50  20  68  30  86  40  104  1  34  11  52  21  70  31  88  41  106  2  36  12  54  22  72  32  90  42  108  3  37  13  55  23  73  33  91  43  109  4  39  14  57  24  75  34  93  44  111  5  41  15  59  25  77  35  95  45  113  6  43  16  61  26  79  36  97  46  115  7  45  17  63  27  81  37  99  47  117  8  46  18  64  28  82  38  100  48  118  9  48  19  66  29  84  39  102  49  120  °C  °F  °C  °F  °C  °F  °C  °F  °C  °F  50  122  60  140  70  158  80  176  90  194  51  124  61  142  71  160  81  178  91  196  52  126  62  144  72  162  82  180  92  198  53  127  63  145  73  163  83  181  93  199  54  128  64  147  74  165  84  183  94  201  55  131  65  149  75  167  85  185  95  203  56  133  66  151  76  169  86  187  96  205  57  135  67  152  77  170  87  188  97  207  58  136  68  154  78  172  88  190  98  208  59  139  69  158  79  174  89  192  99  210  Alphanumeric Conversion Table Display Reading (Alphanumeric)  °C  °F  %  A1 thru A9  -1 thru -9  30 thru 16  -1 thru -9  B0 thru B9  -10 thru -19    14 thru -2  -10 thru -19  C0 thru C9  -20 thru -29   -4 thru -20  -20 thru -29  D0 thru D9  -30 thru -39  -22 thru -38  -30 thru -39  E0 thru E9  -40 thru -49  -40 thru -58  ———  F0 thru F9  -50 thru -59  -58 thru -74  +100 thru +109