How to Troubleshoot the Climate Control

How to Check for DTCs with the HDS


1.Make sure the ignition switch is OFF.

2.Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.

 

3.Turn the ignition switch ON (II).

4.Make sure the HDS communicates with the vehicle and the climate control unit. If it doesn't, troubleshoot the DLC circuit, L13A7 engine, R18A2 engine.

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, 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 with the HDS


1.Make sure the ignition switch is OFF.

2.Connect the HDS to the data link connector (DLC).

3.Turn the ignition switch ON (II).

4.Make sure the HDS communicates with the vehicle and the climate control unit. If it doesn't, troubleshoot the DLC circuit, L13A7 engine, R18A2 engine.

5.Select HVAC/CLIMATE CONTROL in the BODY ELECTRICAL menu.

6.Select INSPECTION in the HVAC/CLIMATE CONTROL menu.

7.Select CLIMATE CONTROL SELF TEST in the INSPECTION menu.

8.Check for DTCs. If any DTCs are indicated, write down the DTCs, then go to the indicated DTC 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 climate control unit has a self-diagnostic function. To run the self-diagnostic function, do the following:

1.Turn the ignition switch OFF.

2.Press and hold the AUTO and RECIRCULATION CONTROL buttons, turn the ignition switch ON (II), then release the AUTO and RECIRCULATION CONTROL buttons.

3.All temperature indicator segments come on for 2 seconds, then self-diagnostic function begins.

NOTE:
  • The blower motor can be run at various speeds regardless of what the panel is displaying.
  • If there is any problem in the system, the driver's temperature indicator will light up the segment (A through P) and AUTO indicator 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 P) and AUTO indicator. To determine the meaning of the DTC, refer to checking for DTCs.
  • If there are no problems detected, the segments will not illuminate, and the system will appear to be turned off.

 

Canceling the Self-diagnostic Function


4.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 DTCs.

Checking for DTCs


The temperature display indicates single or multiple DTCs. If indicator segments A, C, E and G are on at the same time, there may be an open in the common ground wire. If no DTCs are present, the indicator remains blank.

 

DTC (Driver's Temperature Indicator Segment and AUTO Indicator) 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 
J A problem in the driver's air mix control linkage, door, or motor 
K A problem in the passenger's air mix control linkage, door, or motor 
L A problem in the mode control linkage, doors, or motor 
M A problem in the recirculation control linkage, door, or motor 
N A problem in the blower motor 
P Climate control unit internal error 
A and AUTO Climate control unit lost communication with gauge control module (NE message) 
B and AUTO Climate control unit lost communication with gauge control module (ECT message) 
C and AUTO Climate control unit lost communication with recirculation control motor 
D and AUTO Climate control unit lost communication with mode control motor 
E and AUTO Climate control unit lost communication with gauge control module (VSP message) 
F and AUTO Climate control unit lost communication with audio HVAC subdisplay unit (with audio system) or HVAC subdisplay unit (without audio system) 
G and AUTO Driver's air mix control motor failure 
H and AUTO Passenger's air mix control motor failure 
J and AUTO Communication bus line error 
K and AUTO Climate control unit lost communication with each control motor 
L and AUTO Climate control unit lost communication with driver's air mix control motor 
M and AUTO Climate control unit lost communication with passenger's air mix control motor 
N and AUTO Mode control motor failure 
P and AUTO Recirculation control motor failure 

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 temperature, 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 28 °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 MODE buttons, then start the engine.

3.After the engine starts, release both 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 A/C button.

Sensor Item Displayed Value 
1 In-car Temperature °C 
2 Outside Air Temperature °C 
3 Solar Radiation Sensor Value: Dark = 00, Flashlight = 04, Cloudy = 10,
Sunny = 65 		10 kcal/m2·h 
4 Evaporator Outlet Air Temperature °C 
5 Driver's Air Mix Opening (Low value indicates cooler air distribution, higher value indicates warmer air distribution) % of opening 
6 Passenger's Air Mix Opening (Low value indicates cooler air distribution, higher value indicates warmer air distribution) % of opening 
7 Mode Positioning % of opening 
8 Recirculation Opening % of opening 
9 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 a known-good sensor, and recheck.

5.To cancel the sensor input display mode, press the AUTO button or turn the ignition switch 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 -40 thru -49 
F0 thru F9 ——— ——— +100 thru +109