AIR CONDITIONING SYSTEM, Diagnostic DTC:B1412/12

DTC Code DTC Name
B1412/12 Ambient Temperature Sensor Circuit

DESCRIPTION

The ambient temperature sensor is installed in front of the condenser to detect the ambient temperature which is used to control the air conditioner "AUTO" mode. This sensor is connected to the A/C amplifier and detects fluctuations in the ambient temperature. This data is used for controlling the cabin temperature. The sensor sends a signal to the A/C amplifier. The resistance of the ambient temperature sensor changes in accordance with the ambient temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The A/C amplifier applies voltage (5 V) to the ambient temperature sensor and reads voltage changes as the resistance of the ambient temperature sensor changes.

DTC No. DTC Detection Condition Trouble Area
B1412/12 Open or short in ambient temperature sensor circuit

  • Ambient temperature sensor

  • Harness or connector between ambient temperature sensor and A/C amplifier

  • A/C amplifier

WIRING DIAGRAM

A0163CBE06

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the intelligent tester on.

    4. Select the item below in the Data List, and read the display on the intelligent tester.

      Data List / Air Conditioner
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note

      Ambient Temp Sensor

      (Ambi Temp Sens)

      		 Ambient temperature sensor / Min: -23.3°C (-9.94°F), Max: 65.95°C (150.71°F) Actual ambient temperature is displayed

      Open in circuit: -23.3°C (-9.94°F)

      Short in circuit: 65.95°C (150.71°F)
      OK
      The display is as 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) C

    B

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    C

    REPLACE A/C AMPLIFIER Click here

    A

  2. INSPECT AMBIENT TEMPERATURE SENSOR


    1. Remove the ambient temperature sensor.

    2. A0162YVE01

      Disconnect the ambient temperature sensor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B5-1 - B5-2 10°C (50°F) 3.00 to 3.73 kΩ
      B5-1 - B5-2 15°C (59°F) 2.45 to 2.88 kΩ
      B5-1 - B5-2 20°C (68°F) 1.95 to 2.30 kΩ
      B5-1 - B5-2 25°C (77°F) 1.60 to 1.80 kΩ
      B5-1 - B5-2 30°C (86°F) 1.28 to 1.47 kΩ
      B5-1 - B5-2 35°C (95°F) 1.00 to 1.22 kΩ
      B5-1 - B5-2 40°C (104°F) 0.80 to 1.00 kΩ
      B5-1 - B5-2 45°C (113°F) 0.65 to 0.85 kΩ
      B5-1 - B5-2 50°C (122°F) 0.50 to 0.70 kΩ
      B5-1 - B5-2 55°C (131°F) 0.44 to 0.60 kΩ
      B5-1 - B5-2 60°C (140°F) 0.36 to 0.50 kΩ

      Note


      • Hold the sensor only by its connector. Touching the sensor may change the resistance value.

      • When measuring, the sensor temperature must be the same as the ambient temperature.

      Tech Tips

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


    NG

    REPLACE AMBIENT TEMPERATURE SENSOR Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR - A/C AMPLIFIER)


    1. A0162IGE02

      Disconnect the A/C amplifier connector.

    2. A0161YNE03

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      J58-36 (TAM) - B5-1 Always Below 1 Ω
      J58-37 (SG) - B5-2 Always Below 1 Ω
      J58-36 (TAM) - Body ground Always 10 kΩ or higher
      J58-37 (SG) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE A/C AMPLIFIER Click here