B1411/11
Diagnostic trouble codes
DESCRIPTION
The A/C room temperature sensor is installed in the instrument panel to detect the cabin temperature and control the heater and air conditioner "AUTO" function. The resistance of the A/C room temperature sensor changes in accordance with the cabin temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.The A/C amplifier assembly applies voltage (5 V) to the A/C room temperature sensor and reads voltage changes as the resistance of the A/C room temperature sensor changes. This sensor also sends appropriate signals to the A/C amplifier assembly. The room temperature sensor is integrated with the room humidity sensor.
| DTC No. |
DTC Detecting Condition |
Trouble Area |
| B1411/11 |
Open or short in room temperature sensor circuit |
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WIRING DIAGRAM
INSPECTION PROCEDURE
| 1. READ VALUE OF INTELLIGENT TESTER |
Connect the intelligent tester to the DLC3.
Turn the ignition switch ON and push the intelligent tester main switch on.
Select the item below in the DATA LIST, and read the display on the intelligent tester.
| Item |
Measurement Item/Display (Range) |
Normal Condition |
Diagnostic Note |
| ROOM TEMP |
Room temperature sensor / min.: -6.5°C (20.3°F) max.: 57.25°C (135.05°F) |
Actual cabin temperature is displayed |
Open in the circuit: -6.5°C (20.3°F) Short in the circuit: 57.25°C (135.05°F) |
- OK:
- The display is as specified in the normal condition.
- Result:
Result
Proceed to
NG
A
OK (Checking from the PROBLEM SYMPTOMS TABLE)
B
OK (Checking from the DTC)
C
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| A | |
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| 2. INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY |
Remove the A/C amplifier assembly with the connectors still connected.
Measure the voltage according to the value(s) in the table below.
- Voltage:
Tester connection
(Symbols)
Condition
Specified condition
A11-21 (TR) - A11-26 (SG-5)
Ignition switch ON
at 25°C (77°F)
1.8 to 2.2 V
A11-21 (TR) - A11-26 (SG-5)
Ignition switch ON
at 40°C (104°F)
1.3 to 1.7 V
- HINT:
- As the temperature increases, the voltage decreases.
- Result:
Result
Proceed to
NG
A
OK (Checking from the PROBLEM SYMPTOMS TABLE)
B
OK (Checking from the DTC)
C
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| A | |
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| 3. INSPECT A/C ROOM TEMPERATURE SENSOR |
Remove the A/C room temperature sensor.
Disconnect the connector from the A/C room temperature sensor.
Measure the resistance according to the value(s) in the table below.
- Resistance:
Tester connection
(Symbols)
Condition
Specified condition
A33-1 (THR) - A33-2 (GND)
10°C (50°F)
3.00 to 3.73 kΩ
A33-1 (THR) - A33-2 (GND)
15°C (59°F)
2.45 to 2.88 kΩ
A33-1 (THR) - A33-2 (GND)
20°C (68°F)
1.95 to 2.30 kΩ
A33-1 (THR) - A33-2 (GND)
25°C (77°F)
1.60 to 1.80 kΩ
A33-1 (THR) - A33-2 (GND)
30°C (86°F)
1.28 to 1.47 kΩ
A33-1 (THR) - A33-2 (GND)
35°C (95°F)
1.00 to 1.22 kΩ
A33-1 (THR) - A33-2 (GND)
40°C (104°F)
0.80 to 1.00 kΩ
A33-1 (THR) - A33-2 (GND)
45°C (113°F)
0.65 to 0.85 kΩ
A33-1 (THR) - A33-2 (GND)
50°C (122°F)
0.50 to 0.70 kΩ
A33-1 (THR) - A33-2 (GND)
55°C (131°F)
0.44 to 0.60 kΩ
A33-1 (THR) - A33-2 (GND)
60°C (140°F)
0.36 to 0.50 kΩ
- NOTICE:
- Even slightly touching the sensor may change the resistance value. Be sure to hold the connector of the sensor.
- When measuring, the sensor temperature must be the same as the ambient temperature.
- Even slightly touching the sensor may change the resistance value. Be sure to hold the connector of the sensor.
- HINT:
- As the temperature increases, the resistance decreases (see the graph).
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| OK | |
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| 4. CHECK HARNESS AND CONNECTOR (A/C ROOM TEMPERATURE SENSOR - A/C AMPLIFIER ASSEMBLY) |
Disconnect the connector from the A/C amplifier assembly.
Measure the resistance according to the value(s) in the table below.
- Resistance:
Tester connection
(Symbols)
Condition
Specified condition
A11-21 (TR) - A33-1 (THR)
Always
Below 1 Ω
A11-26 (SG-5) - A33-2 (GND)
Always
Below 1 Ω
A11-21 (TR) - Body ground
Always
10 kΩ or higher
A11-26 (SG-5) - Body ground
Always
10 kΩ or higher
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| OK | ||
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