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AIR CONDITIONING SYSTEM, Diagnostic DTC:B1492

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DTC Code DTC Name
B1492 Communication Malfunction (IR Sensor)
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DESCRIPTION

The infrared ray sensor, which is installed on the rear roof, detects human body temperature and controls the heater and air conditioner "AUTO" mode in 4 zones. Signals are transmitted to the air conditioning amplifier via the LIN communication line. This DTC is output when the temperature of the physical object is detected as -30°C (-22°F) or less, or 80°C (176°F) or more for 10 seconds or more.

DTC No. Detection Item DTC Detection Condition Trouble Area Memory
B1492 Communication Malfunction (IR Sensor)

  • Diagnosis condition: None

  • Malfunction status: Open or short in infrared rays sensor circuit

  • Detection time: None (Present malfunction), continuously for 8.5 minutes or more (Past malfunction)

  • Map light assembly

  • Infrared ray sensor

  • Harness or connector

  • Air conditioning amplifier assembly

 Memorized
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WIRING DIAGRAM

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CAUTION / NOTICE / HINT

Note:

Inspect the fuses for circuits related to this system before performing the following procedure.

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PROCEDURE


  1. Click here

    CHECK HARNESS AND CONNECTOR (MAP LIGHT ASSEMBLY - BATTERY AND BODY GROUND)


    1. Disconnect the map light assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      N7-22 (GND) - Body ground Always Below 1 Ω

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      N9-1 (IG) - Body ground Power switch on (IG) 11 to 14 V
      Power switch off Below 1 V
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  2. Click here

    CHECK HARNESS AND CONNECTOR (MAP LIGHT ASSEMBLY - AIR CONDITIONING AMPLIFIER ASSEMBLY)


    1. Disconnect the N9 map light assembly connector.

    2. Disconnect the G65 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
      N9-7 (LIN) - G65-16 (LIN3) Always Below 1 Ω
      N9-7 (LIN) or G65-16 (LIN3) - Other terminals and body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  3. Click here

    CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY (OUTPUT SIGNAL)


    1. Disconnect N9 map light assembly connector.

    2. B004V89C02
      *a Waveform

      Using an oscilloscope, check the waveform.

      Item Content
      Tester Connection N9-7 (LIN) - Body ground
      Tool Setting 2 V/DIV., 20 ms/DIV.
      Condition Power switch on (IG)
      OK
      The waveform displays properly.
      Result
      Proceed to
      OK
      NG

  4. Click here

    CHECK MAP LIGHT ASSEMBLY (OUTPUT SIGNAL)


    1. B004SHHC01
      *a

      Component with harness connected

      (Air Conditioning Amplifier Assembly)
      *b Waveform

      Using an oscilloscope, check the waveform.

      Item Content
      Tester Connection G65-16 (LIN3) - Body ground
      Tool Setting 2 V/DIV., 20 ms/DIV.
      Condition Power switch on (IG)
      OK
      The waveform displays properly.
      Result
      Proceed to
      OK
      NG

  5. Click here

    INSPECT MAP LIGHT ASSEMBLY


    1. B004RNFN01

      Remove the map light assembly.

      Click here

    2. Remove the infrared ray sensor from the map light assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A-1 - C-1(IG) Always Below 1 Ω
      A-3 - B-22 (GND) Always Below 1 Ω
      A-5 - 7 (LIN) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG