AIR CONDITIONING SYSTEM, Diagnostic DTC:B1468/68

DTC Code DTC Name
B1468/68 Rear Passenger Side Room Temperature Sensor Circuit

DESCRIPTION

The rear room temperature sensor RH is installed in the rear door trim board RH 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 RH seat. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The rear door ECU RH sends the read signal to the air conditioning amplifier via the CAN communication line. The rear door ECU RH 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 RH.

Tech Tips


  • The rear temperature sensor for RHD vehicle is installed at driver's side.

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

DTC Code DTC Detection Condition Trouble Area
B1468/68 Open or short in rear room temperature sensor RH circuit

  • Rear room temperature sensor RH

  • Harness or connector between rear room temperature sensor RH and rear door ECU RH

  • Rear door ECU RH

  • Air conditioning amplifier

  • CAN communication line

WIRING DIAGRAM

A01GZ0JE04

INSPECTION PROCEDURE

PROCEDURE


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


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

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

      Rear room temperature sensor (for RH seat) /

      Min.: -6.5°C (20.3°F)

      Max.: 57.25°C (135.05°F)

      		 Actual rear room temperature for RH 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.

    NG

    INSPECT REAR ROOM TEMPERATURE SENSOR RH Click here

    OK

    REPLACE AIR CONDITIONING AMPLIFIER Click here

  2. INSPECT REAR ROOM TEMPERATURE SENSOR RH

    A01GW73E02

    1. Remove the rear room temperature sensor RH 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
      15°C (59°F) 2.45 to 2.88 kΩ
      20°C (68°F) 1.95 to 2.30 kΩ
      25°C (77°F) 1.60 to 1.80 kΩ
      30°C (86°F) 1.28 to 1.47 kΩ
      35°C (95°F) 1.00 to 1.22 kΩ
      40°C (104°F) 0.80 to 1.00 kΩ
      45°C (113°F) 0.65 to 0.85 kΩ
      50°C (122°F) 0.50 to 0.70 kΩ
      55°C (131°F) 0.44 to 0.60 kΩ
      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 RH Click here

    OK

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

    A01GWAVE01

    1. Disconnect the Q4 rear room temperature sensor RH connector.

    2. Disconnect the O2 rear door ECU RH connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      Q4-2 - O2-26 (TRE) Always Below 1 Ω
      Q4-1 - O2-13 (TRAD)
      O2-26 (TRE) - Body ground Always 10 kΩ or higher
      O2-13 (TRAD) - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE REAR DOOR ECU RH Click here