DTC    B1411/11    Room Temperature Sensor Circuit

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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
  1. A/C room temperature sensor
  2. Harness or connector between cooler A/C room temperature sensor and A/C amplifier assembly
  3. A/C amplifier assembly

WIRING DIAGRAM


E108928E06


INSPECTION PROCEDURE

1.READ VALUE OF INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch ON and push the intelligent tester main switch on.

  1. Select the item below in the DATA LIST, and read the display on the intelligent tester.


DATA LIST / AIR CONDITIONER 
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



B
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
A


2.INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY


    E109265E24

  1. Remove the A/C amplifier assembly with the connectors still connected.

  1. 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



B
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
A


3.INSPECT A/C ROOM TEMPERATURE SENSOR


    E108929E08

  1. Remove the A/C room temperature sensor.

  1. Disconnect the connector from the A/C room temperature sensor.



  1. Measure the resistance according to the value(s) in the table below.


    I040673E01

    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:
    1. Even slightly touching the sensor may change the resistance value. Be sure to hold the connector of the sensor.
    2. When measuring, the sensor temperature must be the same as the ambient temperature.

    HINT:
    As the temperature increases, the resistance decreases (see the graph).



NG
REPLACE A/C ROOM TEMPERATURE SENSOR
OK


4.CHECK HARNESS AND CONNECTOR (A/C ROOM TEMPERATURE SENSOR - A/C AMPLIFIER ASSEMBLY)


    E108939E05

  1. Disconnect the connector from the A/C amplifier assembly.

  1. 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



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY