How to Troubleshoot the Heating
How to Check for DTCs with the HDS
  1. Make sure the ignition switch is OFF.
  1. Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.
  1. Turn the ignition switch ON (II).
  1. Make sure the HDS communicates with the vehicle and the heater control unit. If it doesn't, troubleshoot the DLC circuit.
  1. Select HVAC/CLIMATE CONTROL in the BODY ELECTRICAL menu.
  1. Select DTCs in the HVAC/CLIMATE CONTROL menu.
  1. 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.
  1. Connect the HDS to the data link connector (DLC).
  1. Turn the ignition switch ON (II).
  1. Make sure the HDS communicates with the vehicle and the heater control unit. If it doesn't, troubleshoot the DLC circuit.
  1. Select HVAC/CLIMATE CONTROL in the BODY ELECTRICAL menu.
  1. Select INSPECTION in the HVAC/CLIMATE CONTROL menu.
  1. Select CLIMATE CONTROL SELF TEST in the INSPECTION menu.
  1. 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 heater control unit has a self-diagnostic function. To run the self-diagnostic function, do the following:
  1. Turn the ignition switch OFF.
  1. Press and hold the AUTO and RECIRCULATION CONTROL buttons, turn the ignition switch ON (II), then release the AUTO and RECIRCULATION CONTROL buttons.
  1. 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 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

  1. 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 (Temperature Indicator Segment and AUTO Indicator)
Detection Item
A
B
C
D
E
F
G *1
H *2
J
L
M
N
P
A and AUTO
B and AUTO
C and AUTO
D and AUTO
E and AUTO
G and AUTO
J and AUTO
K and AUTO
L and AUTO
N and AUTO
P and AUTO

*1:
The evaporator temperature sensor is not equipped for the only heater model (without A/C model). So the heater control unit stores DTC 1231 or DTC G even if the system is normal.
*2:
The evaporator temperature sensor is not equipped for the only heater model (without A/C model).

Displaying Sensor Inputs at the Heater Control Unit
The heater control unit has a mode that displays sensor inputs it receives. This mode shows you what the heater 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.
  1. 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 heater control logic.
  1. Turn the ignition switch OFF.
To run the sensor input display mode, follow these steps
  1. Turn the ignition switch OFF.
  1. Press and hold both the AUTO and MODE buttons, then start the engine.
  1. 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.
  1. To advance to the next sensor, press the REAR WINDOW DEFOGGER 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/m 2 ·h
    4
    ———
    ———
    5
    Air Mix Opening (Low value indicates cooler air distribution, higher value indicates warmer air distribution)
    % of opening
    6
    ———
    ———
    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.
  1. 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
    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