DSD Information System
Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Heating / Air Conditioning System (Except HV, W/ Auto A/C) - Diagnostic Codes (2 Of 2) >> AIR CONDITIONING SYSTEM (for Gasoline Model with Automatic Air Conditioning System) >> DTC B1497: Communication Malfunction (Bus Ic) [10/2022 - 11/2023] >> Procedure

DTC B1497: Communication Malfunction (Bus Ic) [10/2022 - 11/2023]: Procedure

  1. PERFORM ACTIVE TEST USING GTS (SERVO PULSE) 
    1. Perform the Active Test according to the display on the GTS.

      Body Electrical > Air Conditioner > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      Air Mix Servo Targ Pulse(D) No. 1 air conditioning radiator damper servo sub-assembly (driver side air mix) pulse Min.: 128
      Max.: 383      		 Operates between 165 to 257 pulses
      Air Mix Servo Targ Pulse(P) No. 1 air conditioning radiator damper servo sub-assembly (front passenger side air mix) pulse Min.: 128
      Max.: 383      		 Operates between 255 to 347 pulses
      Air Outlet Servo Pulse (D) No. 1 air conditioning radiator damper servo sub-assembly (front side mode) pulse Min.: 128
      Max.: 383      		 Operates between 234 to 348 pulses
      Air Inlet Damper Targ Pulse No. 1 blower damper servo sub-assembly pulse Min.: 128
      Max.: 383      		 Operates between 220 to 256 pulses

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      Air Mix Servo Targ Pulse(D)

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      Air Mix Servo Targ Pulse(P)

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      Air Outlet Servo Pulse (D)

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      Air Inlet Damper Targ Pulse

      OK

      Damper servo motor is operated.

      Result

      Result  Proceed to
      All damper servo motors are not operated A
      Any damper servo motor is not operated B
      All damper servo motors are operated C

    Result: 

    B 

    REPLACE AIR CONDITIONING HARNESS ASSEMBLY. Refer to  DISASSEMBLY [10/2022 - 11/2023] 

    Result: 

    C 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    A 

    See step  2

  2. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY 
    1. Disconnect the z18 air conditioning amplifier assembly connector.
      GTY918000Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Air Conditioning Amplifier Assembly)      		 - -
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      z18-2 (BUS G) - Body ground Always Below 1 Ω
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      z18-4 (B BUS) - z18-2 (BUS G) Ignition switch off 11 to 14 V
    4. Using an oscilloscope, check the waveform.
      Item Content
      Tester Connection z18-3 (BUS) - z18-2 (BUS G)
      Tool Setting 2 V/DIV., 20 μs/DIV.
      Condition Ignition switch ON

      OK

      The waveform displays properly.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE AIR CONDITIONING HARNESS ASSEMBLY. Refer to  DISASSEMBLY [10/2022 - 11/2023] 

    Result: 

    NG 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [10/2022 - 11/2023] 

Diesel-Data.com