AIR CONDITIONING SYSTEM, Diagnostic DTC:B1419/19

DTC Code DTC Name
B1419/19 Rear Room Temperature Sensor Circuit

DESCRIPTION

The rear room temperature sensor LH is installed in the rear door trim board LH to detect the rear room temperature and control the heater and air conditioner "AUTO" mode. The resistance of the rear room temperature sensor changes in accordance with the rear room temperature for LH seat. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The rear door ECU LH sends the read signal to the air conditioning amplifier via the CAN communication line. The rear door ECU LH applies voltage (5 V) to the rear room temperature sensor and reads voltage changes as the resistance of the rear room temperature sensor changes. This sensor also sends the appropriate signals to the rear door ECU LH.

Tech Tips

This circuit uses the CAN communication line. Before performing the inspection, check that the CAN communication system is functioning normally.

DTC No. DTC Detection Condition Trouble Area
B1419/19 Open or short in rear room temperature sensor LH circuit

  • Rear room temperature sensor LH

  • Harness and connector between rear room temperature sensor LH and rear door ECU LH

  • Rear door ECU LH

  • Air conditioning amplifier

  • CAN communication line

WIRING DIAGRAM

A001A8EE12

PROCEDURE


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


    1. Use the Data List to check if the rear room temperature sensor for LH seat is functioning properly.

      Air Conditioner
      Tester Display Measurement Item / Range Normal Condition Diagnostic Note
      Room Temp Sensor (Rear)

      Rear room temperature sensor for LH seat /

      Min.: -6.5°C (20.3°F)

      Max.: 57.25°C (135.05°F)

      		 Actual rear room temperature for LH seat is displayed

      Open in circuit: -6.5°C (20.3°F)

      Short in circuit: 57.25°C (135.05°F)
      OK
      The display is as specified in the normal condition.
      Result
      Result Proceed to
      NG A
      OK (Checking from the PROBLEM SYMPTOMS TABLE) B
      OK (Checking from the DTC) C

    B

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

    C

    REPLACE AIR CONDITIONING AMPLIFIER Click here

    A

  2. INSPECT REAR ROOM TEMPERATURE SENSOR LH

    A0019OCE01

    1. Remove the rear room temperature sensor LH Click here.

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

      Note

      Even slightly touching the sensor may change the resistance value. Be sure to hold the connector of the sensor.

      Tech Tips

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


    NG

    REPLACE REAR ROOM TEMPERATURE SENSOR LH Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (REAR ROOM TEMPERATURE SENSOR LH - REAR DOOR ECU LH)

    A001EW3E01
    *1 Front view of wire harness connector: (to Rear Room Temperature Sensor LH)
    *2 Front view of wire harness connector: (to Rear Door ECU LH)
    *3 TRAD
    *4 TRE

    1. Disconnect the Q9 rear room temperature sensor LH connector.

    2. Disconnect the O15 rear door ECU LH connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      Q9-2 - O15-26 (TRE) Always Below 1 Ω
      Q9-1 - O15-13 (TRAD) Always Below 1 Ω
      O15-26 (TRE) - Body ground Always 10 kΩ or higher
      O15-13 (TRAD) - Body ground Always 10 kΩ or higher

    OK

    REPLACE REAR DOOR ECU LH

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR