DTC    B1411/11    Room Temperature Sensor Circuit

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DESCRIPTION

The room temperature sensor (cooler thermistor) is installed in the instrument panel to detect the room temperature and control the heater and air conditioner AUTO mode. The resistance of the room temperature sensor (cooler thermistor) changes in accordance with the room temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.
The air conditioning amplifier applies a voltage (5V) to the room temperature sensor (cooler thermistor) and reads voltage changes as the resistance of the room temperature sensor (cooler thermistor) changes. This sensor also sends the appropriate signals to the air conditioning amplifier.

DTC No.
DTC Detection Condition
Trouble Area
B1411/11
Open or short in room temperature sensor circuit
  1. Room temperature sensor (cooler thermistor)
  2. Harness and connector between room temperature sensor (cooler thermistor) and air conditioning amplifier
  3. Air conditioning amplifier

WIRING DIAGRAM


E115796E17


INSPECTION PROCEDURE

1.READ VALUE USING INTELLIGENT TESTER (ROOM TEMPERATURE SENSOR)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the intelligent tester on.

  1. Enter the following menus: Body / Air Conditioner / Data List.

  1. According to the display on the intelligent tester, read the Data List.

    Air Conditioner 
    Item
    		Measurement Item/Display (Range)
    		Normal Condition
    		Diagnostic Note
    Room Temperature Sensor
    		Room temperature sensor /
    Min.: -6.5°C (20.3°F)
    Max.: 57.25°C (135.05°F)
    		Actual room temperature is displayed
    		Open circuit: -6.5°C (20.3°F)
    Short circuit: 57.25°C (135.05°F)

    OK:
    The display is specified in the normal condition column.


    Result 
    Result
    		Proceed to
    NG
    		A
    OK (When troubleshooting according to the Problem Symptoms Table)
    		B
    OK (When troubleshooting according to the DTC output)
    		C



B
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE (Click here)

C
REPLACE AIR CONDITIONING AMPLIFIER (Click here)
A


2.INSPECT ROOM TEMPERATURE SENSOR (COOLER THERMISTOR)
E117004E22

  1. Remove the room temperature sensor (cooler thermistor).

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    1 - 2
    		10°C (50°F)
    		3.00 to 3.73 kΩ
    15°C (59°F)
    		2.45 to 2.88 kΩ
    20°C (68°F)
    		1.95 to 2.30 kΩ
    25°C (77°F)
    		1.60 to 1.80 kΩ
    30°C (86°F)
    		1.28 to 1.47 kΩ
    35°C (95°F)
    		1.00 to 1.22 kΩ
    40°C (104°F)
    		0.80 to 1.00 kΩ
    45°C (113°F)
    		0.65 to 0.85 kΩ
    50°C (122°F)
    		0.50 to 0.70 kΩ
    55°C (131°F)
    		0.44 to 0.60 kΩ
    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).

  1. Reinstall the room temperature sensor (cooler thermistor).



NG
REPLACE ROOM TEMPERATURE SENSOR (COOLER THERMISTOR) (Click here)
OK


3.CHECK HARNESS AND CONNECTOR (ROOM TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER)


    E115797E09

  1. Disconnect the D11 room temperature sensor (cooler thermistor) connector.

  1. Disconnect the D15 air conditioning amplifier connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    D11-1 - D15-29 (TR)
    		Always
    		Below 1 Ω
    D11-2 - D15-34 (SG-1)
    		Always
    		Below 1 Ω
    D11-1 - Body ground
    		Always
    		10 kΩ or higher
    D11-2 - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the room temperature sensor (cooler thermistor) connector.

  1. Reconnect the air conditioning amplifier connector.
    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to Room Temperature Sensor (Cooler Thermistor))
    *2
    		Rear view of wire harness connector
    (to Air Conditioning Amplifier)



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER (Click here)