DTC    B1412    Ambient Temperature Sensor Circuit


DESCRIPTION

The thermistor assembly (ambient temperature sensor) is installed in the front part of the cooler condenser assembly to detect the ambient temperature and control the air conditioning auto mode. The sensor connected to the combination meter assembly detects fluctuations in the ambient temperature. This data is used for controlling the room temperature. The sensor sends a signal to the combination meter assembly. The resistance of the thermistor assembly (ambient temperature sensor) changes in accordance with the cooler thermistor temperature (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 (ambient temperature sensor) and reads voltage changes as changes in the resistance of the thermistor assembly (ambient temperature sensor). The combination meter assembly sends these signals to the air conditioning amplifier assembly.

DTC No.
DTC Detection Condition
Trouble Area
B1412
An open or short in the thermistor assembly (ambient temperature sensor) circuit.
  1. Thermistor assembly (ambient temperature sensor)
  2. Harness or connector
  3. Air conditioning amplifier assembly
  4. Combination meter assembly
  5. CAN communication system

WIRING DIAGRAM


E226035E02


INSPECTION PROCEDURE

1.CHECK FOR DTC (CAN COMMUNICATION SYSTEM)

  1. Use the Techstream to check if the CAN communication system is functioning normally.

    OK:
    CAN DTC is not output


NG
GO TO CAN COMMUNICATION SYSTEM (Click here)
OK


2.READ VALUE USING TECHSTREAM

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

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

  1. According to the display on the Techstream, read the Data List.

    Combination Meter 
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Ambient Temperature
    		Ambient temperature sensor /
    Min.: -40°C (-40°F)
    Max.: 87.5°C (189.5°F)
    		Actual ambient temperature is displayed
    		-

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


NG
Go to step 7
OK


3.READ VALUE USING TECHSTREAM

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

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

  1. According to the display on the Techstream, read the Data List.

    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 is displayed
    		-

    OK:
    The display is as specified in the normal condition column.
    Result 
    Result
    		Proceed to
    OK (When troubleshooting according to the DTC)
    		A
    OK (When troubleshooting according to Problem Symptoms Table)
    		B
    NG
    		C


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

C
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (Click here)
A


4.CHECK FOR DTC

  1. Clear the DTCs (Click here).

  1. Check for DTCs (Click here).

    OK:
    DTC B1412 is not output


NG
Go to step 5
OK

USE SIMULATION METHOD TO CHECK (Click here)  

5.REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

  1. Temporarily replace the air conditioning amplifier assembly with a new or normally functioning one (Click here).


NEXT


6.CHECK FOR DTC

  1. Clear the DTCs (Click here).

  1. Check for DTCs (Click here).

    OK:
    DTC B1412 is not output


NG
REPLACE COMBINATION METER ASSEMBLY (Click here)
OK

END (AIR CONDITIONING AMPLIFIER ASSEMBLY IS FAULTY) 

7.INSPECT THERMISTOR ASSEMBLY (AMBIENT TEMPERATURE SENSOR)

  1. Inspect the thermistor assembly (ambient temperature sensor) (Click here).



NG
REPLACE THERMISTOR ASSEMBLY (AMBIENT TEMPERATURE SENSOR) (Click here)
OK


8.CHECK HARNESS AND CONNECTOR (THERMISTOR ASSEMBLY (AMBIENT TEMPERATURE SENSOR) - AIR CONDITIONING AMPLIFIER ASSEMBLY)

  1. Disconnect the A61 thermistor assembly (ambient temperature sensor) connector.

  1. Disconnect the D100 combination meter assembly connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A61-2 - D100-35 (TX1+)
    		Always
    		Below 1 Ω
    A61-1 - D100-34 (TX1-)
    		Always
    		Below 1 Ω
    A61-2 - Body ground
    		Always
    		10 kΩ or higher
    A61-1 - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE COMBINATION METER ASSEMBLY (Click here)