HVAC
HVAC System Troubleshooting & Testing - CR-V
HOW TO TROUBLESHOOT THE CLIMATE CONTROL SYSTEM
HOW TO CHECK FOR DTCS WITH THE HDS
NOTE:
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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).
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The second method is to run the self-diagnostic function built into the
climate control unit.
The third method is to use the B-CAN SYSTEM DIAGNOSIS TEST MODE
A .
1. Make sure the ignition switch is in LOCK (0).
2. Connect the HDS to the DLC (A) located under the driver's side of the dashboard.
Fig. 1: Identifying Data Link Connector (DLC)
Courtesy of AMERICAN HONDA MOTOR CO., INC.
3. Turn the ignition switch to ON (II).
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 HVAC/Climate Control in the BODY ELECTRICAL menu.
6. Select DTCs in the HVAC/Climate Control Mode 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, do all system scan, then refer to symptom troubleshooting.
NOTE:
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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 ignition switch is in LOCK (0).
2. Connect the HDS to the DLC.
3. Turn the ignition switch to ON (II).
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 HVAC/Climate Control in the BODY ELECTRICAL menu.
6. Select Inspection in the HVAC/Climate Control Mode Menu.
7. Select Climate Control Unit 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:
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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 to LOCK (0), and then back to ON (II).
2. Press and hold the ON/OFF button, then within 10 seconds press and release the REAR WINDOW
DEFOGGER/MIRROR DEFOGGER* button five times. Release the ON/OFF button.
*: With mirror defogger
3. ALL LCD segments come on for 2 seconds, then the self-diagnostic function begins.
NOTE:
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The blower motor will run at various speeds regardless of what the
panel is displaying.
If there is any problem in the system, the system flashes 88 or
alternately flashes 88. 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 segment
illuminate) between the DTCs.
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If there are no problems detected, the system will flashes no.
Fig. 2: Identifying Fan Control And ON/OFF Buttons And Driver's Temperature Indicator
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Canceling the Self-Diagnostic Function
4. Turn the ignition switch to LOCK (0) 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.
HOW TO CHECK THE PAST DTC'S
The climate control unit can record DTCs of the past trouble. How to read the past DTC is as follows.
1. Turn the ignition switch to LOCK (0), and then back to ON (II).
2. Press and hold both the AUTO and ON/OFF buttons.
3. During press and hold both the AUTO and ON/OFF buttons, the past trouble is indicate.
NOTE:
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If there is any problem in the system, the system flashes 88 or
alternately flashes 88. 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 segment
illuminate) between the DTCs.
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If there are no problems detected, the system will flashes no.
Fig. 3: Identifying ON/OFF, Auto And Windshield Defroster Buttons And Windshield Defroster
Indicator
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Canceling the read past DTC's
4. Turn the ignition switch to LOCK (0), to cancel the read past DTC's. After completing the repair work,
clear the DTCs.
HOW TO CLEAR THE PAST DTC'S
1. Turn the ignition switch to LOCK (0).
2. Press and hold both the AUTO and WINDSHIELD DEFROSTER buttons, then turn the ignition switch
to ON (II).
3. After about 5 seconds the windshield defroster indicator starts to blink, release the buttons. The indicator
will blink 5 times then stop.
4. Do the How to check the past DTC's to verify DTC's have been cleared.
CHECKING FOR DTCS
The driver's temperature indicator indicates single or multiple DTCs. If no DTCs are present, the indicator will
flashes no.
NOTE:
If the driver's temperature indicator segments 05, 07, 09, 40, 43, 49, 55, and 89
indicator are on at the same time, there may be an open in the sensor common
ground wire.
Fig. 4: Identifying Driver's Temperature Indicator
Courtesy of AMERICAN HONDA MOTOR CO., INC.
DTC (Driver's Temperature
DTC
Detection Item
Indicator Segments)
05
06
07
08
09
0A
40
41
B1227 An open in the outside air temperature sensor circuit
B1228 A short in the outside air temperature sensor circuit
B1229 An open in the sunlight sensor circuit
B1230 A short in the sunlight sensor circuit
B1231 An open in the evaporator temperature sensor circuit
B1232 A short in the evaporator temperature sensor circuit
B1233 An open in the air mix control motor circuit (driver's)
B1234 A short in the air mix control motor circuit (driver's)
A problem in the air mix control motor circuit, linkage,
door, or motor (driver's)
42
B1235
43
44
B1236 An open in the passenger's air mix control motor circuit
B1237 A short in the passenger's air mix control motor circuit
A problem in the passenger's air mix control motor circuit,
linkage, door, or motor
45
B1238
49
4A
B121A An open in the mode control motor circuit
B121B A short in the mode control motor circuit
A problem in the mode control motor circuit, linkage,
door, or motor
4B
B1240
55
56
B2986 An open in the recirculation control motor circuit
B1220 A short in the recirculation control motor circuit
A problem in the recirculation control motor circuit,
linkage, door, or motor
57
B2983
59
80
B1241 A problem in the blower motor circuit
U1280 Communication bus line error (BUS-OFF)
Climate control unit lost communication with gauge
control module (ECT message)
Climate control unit lost communication with gauge
control module (VSP message)
81
83
U128D
U128D
89
B121D Humidity/in-car temperature sensor communication error
C0
--- Climate control unit internal error
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 ignition switch to 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 dial to the desired test temperature:
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"Lo" temperature setting will default to MAX COOL, VENT, and RECIRC (A/C on) or FRESH
(A/C off).
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"Hi" temperature setting will default to MAX HOT, HEAT or HEAT/DEF, and FRESH.
58 through 86 Β°F (14 through 30 Β°C) settings will use the automatic climate control logic.
3. Turn the ignition switch to LOCK (0).
RUN THE SENSOR INPUT DISPLAY MODE
1. Turn the ignition switch to LOCK (0), and then back to ON (II).
2. Press and hold both the AUTO and RECIRCULATION buttons, then start the engine.
Fig. 5: Identifying Recirculation And Auto Buttons
Courtesy of AMERICAN HONDA MOTOR CO., INC.
3. After the engine starts, release both buttons. The climate 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/MIRROR DEFOGGER* button.
*: With mirror defogger
NOTE:
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The sensor values will be displayed in degrees Celsius (Β°C) or an
alphanumeric code. Use the chart to convert the value to degree
Fahrenheit (Β°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, o use
the climate control self-diagnostic function.
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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.
Displayed
Sensor
Item
Value
1
2
3
4
5
Mode positioning
In-car temperature
Outside air temperature
%
Β°C
Β°C
2
Solar radiation sensor value: dark = 00, flashlight = 04, cloudy = 10, sunny = 65
Evaporator outlet air temperature
10 kcal/m .h
Β°C
Driver's air mix opening (low value indicates cooler air distribution, higher value
indicates warmer air distribution)
Passenger's air mix opening (low value indicates cooler air distribution, higher
value indicates warmer air distribution)
6
7
% of opening
% of opening
8
9
A
b
C
d
e
Recirculation control opening
Vehicle speed (vehicle must be driven to display speed)
Engine coolant temperature
Vent temperature air out (TAO) (driver's)
Humidity sensor value
% of opening
10 km/h
Β°C
Β°C
%
Step
-----
Illumination duty
Software version
CELSIUS TO FAHRENHEIT CONVERSION
Β°C Β°F Β°C Β°F Β°C Β°F Β°C Β°F Β°C Β°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
Β°C Β°F Β°C Β°F Β°C Β°F Β°C Β°F Β°C Β°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 77 170 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
Display Reading (Alphanumeric)
A1 thru A9
Β°C
Β°F
%
-1 thru -9 30 thru 16 -1 thru -10
B0 thru B9
C0 thru C9
D0 thru D9
E0 thru E9
E9
-10 thru -19 14 thru -2 -10 thru -19
-20 thru -29 -4 thru -20 -20 thru -29
-30 thru -39 -22 thru -38 -30 thru -39
-40 thru -49 -40 thru -56 -40 thru -49
-50 or less -58 or less -50 or less
ALPHANUMERIC CONVERSION (MODE POSITIONING)
Display Reading (Alphanumeric) Mode Position
0
VENT
HEAT/VENT-1
HEAT/VENT-2
HEAT
HEAT/DEF-1
HEAT/DEF-2
DEF
18
32
54
69
84
F0
HOW TO TROUBLESHOOT THE HEATING AND A/C SYSTEMS
HOW TO USE THE SELF-DIAGNOSTIC FUNCTION
The HVAC control unit has a self-diagnostic function for the heating, ventilation, and air conditioning system.
To run the self-diagnostic function, do the following:
1. Turn the ignition switch to LOCK (0), and then back to ON (II).
2. Set the fan control dial to OFF, temperature control dial to Max Cool, the VENTILATION button to ON.
3. Press and hold the RECIRCULATION button, then within 10 seconds press and release the REAR
WINDOW DEFOGGER/MIRROR DEFOGGER* button five times. Release the RECIRCULATION
button.
*: With mirror defogger
4. The recirculation indicator turns on for 2 seconds, then the self-diagnostic function begins.
NOTE:
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The blower motor will run at various speeds when in the self-
diagnostic mode.
Once the self-diagnostic function is finished, the recirculation
indicator blinks, and the number of blinks indicates the Diagnostic
Trouble Code (DTC) number. If there are multiple DTCs, the indicator
blinks each DTC in sequence from the lowest DTC number to the
highest.
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