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 the front part of the condenser to detect the ambient temperature and control the air conditioner "auto" mode. The sensor connected to the air conditioning amplifier assembly detects fluctuations in the ambient temperature. This data is used for controlling the room temperature. The sensor sends a signal to the air conditioning amplifier assembly. 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 air conditioning amplifier assembly applies voltage (5 V) to the ambient temperature sensor and reads voltage changes as the resistance of the ambient temperature sensor changes.

DTC Code DTC Detection Condition Trouble Area
B1412/12 An open or short in the ambient temperature sensor circuit.

  • Cooler thermistor (ambient temperature sensor)

  • Harness or connector

  • Air conditioning amplifier assembly

WIRING DIAGRAM

B00196FE81
*a Cooler Thermistor (Ambient Temperature Sensor)
*b Air Conditioning Amplifier Assembly

PROCEDURE


  1. READ VALUE USING GTS (AMBIENT TEMP SENSOR)


    1. Use the Data List to check if the cooler thermistor (ambient temperature sensor) is functioning properly Click here.

      Air Conditioner
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Ambient Temp Sensor Ambient temperature sensor / Min: -23.3°C (-9.94°F), Max: 65.95°C (150.71°F) Actual ambient temperature displayed

      Thermistor assembly (ambient temperature sensor) system malfunction:


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

      • Short in the circuit: 65.95°C (150.71°F)
      OK
      The display is as specified in the normal condition.
      Result
      Result Proceed to
      OK (When troubleshooting according to the DTC) A
      OK (When troubleshooting according to Problem Symptoms Table) B
      NG C

    A

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    B

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

    C

  2. INSPECT COOLER THERMISTOR (AMBIENT TEMPERATURE SENSOR)


    1. Remove the cooler thermistor (ambient temperature sensor) Click here.

    2. Inspect the cooler thermistor (ambient temperature sensor) Click here.


    NG

    REPLACE COOLER THERMISTOR (AMBIENT TEMPERATURE SENSOR) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (COOLER THERMISTOR [AMBIENT TEMPERATURE SENSOR] - AIR CONDITIONING AMPLIFIER ASSEMBLY)


    1. Disconnect the A89 cooler thermistor (ambient temperature sensor) connector.

    2. Disconnect the E35 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A89-1 - E35-10 (TAM) Always Below 1 Ω
      A89-2 - E35-32 (SG-2) Always Below 1 Ω
      A89-1 - A89-2 Always 10 kΩ or higher
      A89-1 or E35-10 (TAM) - Body ground Always 10 kΩ or higher
      A89-2 or E35-32 (SG-2) - Body ground Always 10 kΩ or higher

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR