How to Troubleshoot the Climate Control System
How to Check for DTCs with the HDS
NOTE:
There are three methods used to check for DTCs. The recommended method is to use the Honda Diagnostic System (HDS) with the appropriate software, plugged into the data link connector (DLC).
The second method is to run the self-diagnostic function built into the climate control unit.
The third method is to use B-CAN system diagnosis test mode A.

1.
Make sure the vehicle ignition is in the OFF (LOCK) mode.

2.
Connect the HDS to the DLC (A) located under the driver's side of the dashboard.
3.
Turn the vehicle to the ON mode.

4.
Make sure the HDS communicates with the vehicle and the climate control unit. If it does not, go to the DLC circuit troubleshooting.

5.
Select BODY ELECTRICAL in the System Selection Menu.

6.
Select HVAC/Climate Control in the Body Electrical System Select.

7.
Select DTCs in the HVAC/Climate Control Mode Menu.

8.
Check for DTCs. If any DTCs are indicated, write down the DTCs, then go to the indicated DTC troubleshooting. If no DTCs are indicated, do all system scan, then 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
NOTE: This method is only available if the HDS can communicate with the climate control unit.

1.
Make sure the vehicle ignition is in the OFF (LOCK) mode.

2.
Connect the HDS to the DLC.

3.
Turn the vehicle to the ON mode.

4.
Make sure the HDS communicates with the vehicle and the climate control unit. If it does not, go to the DLC circuit troubleshooting.

5.
Select BODY ELECTRICAL in the System Selection Menu.

6.
Select HVAC/Climate Control in the Body Electrical System Select.

7.
Select Inspection in the HVAC/Climate Control Mode Menu.

8.
Select Climate Control Unit Self Test in the Inspection Menu.

9.
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
Icon
Icon Name
AUTO icon
MODE icon
ON/OFF icon
REAR WINDOW DEFOGGER/MIRROR DEFOGGER* icon
RECIRCULATION icon
WINDSHIELD DEFROST icon
*: With mirror defogger

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

1.
Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

2.
Touch the ON/OFF icon to turn on the climate control system if it is off.

3.
Touch and hold the ON/OFF icon, then within 10 seconds touch and release the REAR WINDOW DEFOGGER/MIRROR DEFOGGER* icon five times. Release the ON/OFF icon.

*: With mirror defogger

4.
ALL LCD segments come on for 2 seconds, then the self-diagnostic function begins.

NOTE:
The blower motor will run at various speeds regardless of what the panel is displaying.
If there is any problem in the system, the temperature indicator flashes. Refer to checking for DTCs.
If there is more than one DTC, they are displayed one at a time in sequence followed by a pause (all the display indicator segments illuminate) between the DTCs.
If there are no problems detected, the system will flash “no”.
Canceling the Self-Diagnostic Function
5.
Turn the vehicle to the OFF (LOCK) mode to cancel the self-diagnostic function. After completing any repairs, run the self-diagnostic function again to make sure that there are no other DTCs.

How to Check the History DTCs
The climate control unit can record history DTCs. To read the history DTCs, do the following:

1.
Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

2.
Touch and hold the ON/OFF icon, then within 10 seconds touch and release the MODE icon five times.

3.
While touching and holding both the ON/OFF and MODE icons, the history DTCs will be indicated.

NOTE:
If there is any problem in the system, the temperature indicator flashes. Refer to checking for DTCs.
If there is more than one DTC, they are displayed one at a time in sequence followed by a pause (all the display indicator segments illuminate) between the DTCs.
If there are no problems detected, the system will flash “no”.
Canceling the Read History DTCs
4.
Turn the vehicle to the OFF (LOCK) mode to cancel the read history DTCs. After completing the repair work, clear the DTCs.

How to Clear the History DTCs
1.
Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

2.
Touch and hold the AUTO icon, then within 10 seconds touch and release the WINDSHIELD DEFROST icon five times.

3.
After about 5 seconds the WINDSHIELD DEFROST indicator starts to 5 blinks, release the buttons

4.
Do the How to Check for History DTCs to verify DTCs have been cleared.

Checking for DTCs
The temperature indicator display indicates single or multiple DTCs. If no DTCs are present, the indicator will flash “no”.

DTC (Temperature Indicator Segments)
DTC
Detection Item
05
An open in the outside air temperature sensor circuit
06
A short in the outside air temperature sensor circuit
07*1
An open in the sunlight sensor circuit
08*1
A short in the sunlight sensor circuit
09
An open in the evaporator temperature sensor circuit
0A
A short in the evaporator temperature sensor circuit
17*2
Automatic lighting control unit/sunlight sensor error
40
An open in the air mix control motor circuit
41
A short in the air mix control motor circuit
42
A problem in the air mix control motor circuit, linkage, door, or motor
49
An open in the mode control motor circuit
4A
A short in the mode control motor circuit
4b
A problem in the mode control motor circuit, linkage, door, or motor
55
An open in the recirculation control motor circuit
56
A short in the recirculation control motor circuit
57
A problem in the recirculation control motor circuit, linkage, door, or motor
59
A problem in the blower motor circuit
80
Communication bus line error (BUS-OFF)
81
Climate control unit lost communication with gauge control module (ECT message)
82
Climate control unit lost communication with gauge control module (ILLUMI message)
83
Climate control unit lost communication with gauge control module (VSP message)
89
Humidity/in-car temperature sensor communication error
8E
Electric capacity type switch IC communication error
92*2
Climate control unit lost communication with automatic lighting control unit-sensor
???
Climate control unit internal error
*1: Except
 
'19-20
 
Canada models
*2:
 
'19-20
 
Canada models

Displaying Sensor Inputs at the Climate Control Unit
The climate control unit has a mode that displays the 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.
Checks Before Using the Sensor Input Display Mode
1.
Turn the vehicle to the ON mode, and check the recirculation door function; press the RECIRCULATION icon to switch from FRESH to RECIRCULATE. The air volume and sound should change slightly.

2.
Set the TEMPERATURE CONTROL icon to the desired test temperature:

“Lo” temperature setting will default to MAX COOL, VENT, and RECIRCULATE (A/C on) or FRESH (A/C off).
“HI” temperature setting will default to MAX HOT, HEAT or HEAT/DEF, and FRESH.

3.
Turn the vehicle to the OFF (LOCK) mode.

Run the Sensor Input Display Mode
1.
Turn the vehicle to the ON mode.

2.
Touch and hold the AUTO icon, then within 10 seconds touch and release the RECIRCULATION icon five times.

3.
The temperature indicator will flash the sensor number and then the value for that sensor. Record the value displayed.

4.
To advance to the next sensor, touch the REAR WINDOW DEFOGGER/MIRROR DEFOGGER* icon.

*: With mirror defogger

5.
To cancel the sensor input display mode, turn the vehicle to the OFF (LOCK) mode.
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 use the climate control self-diagnostic function.
If necessary, compare the sensor input display to a known-good vehicle under the same test conditions.
If the sensor displayed value is out of the normal range, refer to the sensor test or substitute a known-good sensor, and recheck.
For unsupported items, “??” will be shown on the display.

Sensor Number
Item
Displayed Value
(Unit)
1
In-car temperature sensor
°C
2
Outside air temperature sensor
°C
3
Sunlight sensor
10 W/m2
4
Evaporator temperature sensor
°C
5
Humidity sensor
%
6
Air mix opening (low value indicates cooler air distribution, higher value indicates warmer air distribution)
% of opening
7
Passenger's air mix opening (low value indicates cooler air distribution, higher value indicates warmer air distribution)
% of opening
8
Mode control opening
% of opening
9
Recirculation control opening
% of opening
A
Vehicle speed (vehicle must be driven to display speed)
10 km/h
b
Engine coolant temperature
°C
C
Vent temperature air out (TAO)
°C
d
Illumination duty
Step
E
Auto idle stop prohibit flag
???
F
Auto idle stop permission time
sec
(Hexadecimal)
G
Electric A/C compressor revolution feedback
100 rpm
H
Not used
???


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
129
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
153
77
171
87
189
97
207
58
136
68
154
78
172
88
190
98
208
59
138
69
156
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 -10
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 -56
-40 thru -49
E9
-50 or less
-58 or less
-50 or less
F0 thru F9
100 thru 109
212 thru 228
100 thru 109
F9
110 or more
230 or more
110 or more


Alphanumeric Conversion Table (Mode Positioning)
Display Reading (%)
Indication
Mode Position
01?03
VENT
22?28
HEAT/VENT
47?53
HEAT
72?78
HEAT/DEF
96?99
DEF