AIR CONDITIONING SYSTEM(for Automatic Air Conditioning System with Top-mounted Air Conditioner Pressure Sensor), Diagnostic DTC:B1412

DTC Code DTC Name
B1412 Ambient Temperature Sensor Circuit

DESCRIPTION

The thermistor assembly is installed in front of the cooler condenser assembly to detect the ambient temperature, which is used to control the air conditioning system. This sensor is connected to the combination meter assembly and detects fluctuations in the ambient temperature. This data is used for controlling the cabin temperature. The sensor sends a signal to the combination meter assembly. The resistance of the thermistor assembly changes in accordance with the ambient temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The combination meter assembly applies a voltage (5 V) to the thermistor assembly and reads voltage changes due to changes in the resistance of the thermistor assembly.

DTC No. Detection Item DTC Detection Condition Trouble Area Memory
B1412 Ambient Temperature Sensor Circuit When the air conditioning amplifier assembly receives out-of-range outside temperature sensor data from the combination meter assembly.

  • Thermistor assembly

  • Harness or connector between thermistor assembly and combination meter assembly

  • Air conditioning amplifier assembly

  • Combination meter assembly

  • CAN communication system

Memorized

(4 seconds or more)*

Tech Tips

If the ambient temperature is approximately -80.0°C (-112°F) or lower, DTC B1412 may be output even though the system is normal.

WIRING DIAGRAM

B008LMYE01

CAUTION / NOTICE / HINT

Note

When replacing the combination meter assembly, always replace it with a new one. If a combination meter assembly which was installed to another vehicle is used, the information stored in it will not match the information from the vehicle and a DTC may be stored.

PROCEDURE


  1. CHECK CAN COMMUNICATION SYSTEM


    1. Check if CAN communication DTCs are output.

      Click here

      Result
      Result Proceed to
      CAN communication DTCs are not output. A
      CAN communication DTCs are output. B

    B

    GO TO CAN COMMUNICATION SYSTEM Click here

    A

  2. READ VALUE USING GTS (AMBIENT TEMPERATURE)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch ON.

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Combination Meter / Data List.

    5. Read the Data List according to the display on the GTS.


      Body Electrical > Combination Meter > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Ambient Temperature Outside temperature

      Min.: -40°C (-40°F)

      Max.: 87.5°C (189.5°F)

      		 Almost the same as actual outside temperature The temperature displayed on the multiinformation display is -40 to 50°C (-40 to 122 °F)

      Body Electrical > Combination Meter > Data List
      Tester Display
      Ambient Temperature
      OK
      The display is as specified in the normal condition column.
      Result
      Result Proceed to
      NG A
      OK (When troubleshooting according to Problem Symptoms Table) B
      OK (When troubleshooting according to the DTC) C

    B

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

    C

    CHECK FOR DTC Click here

    A

  3. INSPECT THERMISTOR ASSEMBLY


    1. Remove the thermistor assembly.

      Click here

    2. Inspect the thermistor assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE THERMISTOR ASSEMBLY Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (THERMISTOR ASSEMBLY - COMBINATION METER ASSEMBLY)


    1. Disconnect the A3 thermistor assembly connector.

    2. Disconnect the F4 combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F4-34 (TEMP) - A3-2 Always Below 1 Ω
      F4-35 (TX1+) - A3-1 Always Below 1 Ω
      F4-34 (TEMP) or A3-2 - Body ground Always 10 kΩ or higher
      F4-35 (TX1+) or A3-1 - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  5. CHECK FOR DTC


    1. Clear the DTCs.

      Click here


      Body Electrical > Air Conditioner > Clear DTCs

    2. Check for DTCs.

      Click here


      Body Electrical > Air Conditioner > Trouble Codes
      Result
      Result Proceed to
      DTCs are not output A
      DTCs are output B

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here