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Home >> Toyota >> 2019 >> Highlander Limited, FWD >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Air Conditioning System (Manual A/C) - Diagnostic Codes & Circuit Tests - (Except Hybrid) >> AIR CONDITIONING SYSTEM (for Manual Air Conditioning System) >> DTC B1497: Communication Malfunction (Bus Ic) [12/2013 - 11/2016] >> Procedure

DTC B1497: Communication Malfunction (Bus Ic) [12/2013 - 11/2016]: Procedure

  1. PERFORM ACTIVE TEST USING TECHSTREAM 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Air Conditioner / Active test.
    5. Check the operation by referring to the table below.

      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 (air mix) pulse Min.: 128
      Max.: 383      		 Operates between 7 to 105 pulses
      Air Outlet Servo Pulse (D) No. 1 air conditioning radiator damper servo sub-assembly (air outlet) pulse Min.: 128
      Max.: 383      		 Operates between 8 to 97 pulses
      Air Inlet Damper Targ Pulse Blower damper servo sub-assembly (air inlet) pulse Min.: 128
      Max.: 383      		 Operates between 7 to 28 pulses
      A/M Servo Pulse(F&R D) Rear air mix damper servo sub-assembly pulse Min.: 128
      Max.: 383      		 Operates between 9 to 54 pulses
      A/O Servo Pulse(F&R D) Rear mode damper servo sub-assembly pulse Min.: 128
      Max.: 383      		 Operates between 7 to 83 pulses

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      Air Mix Servo Targ Pulse(D)

      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

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      A/M Servo Pulse(F&R D)

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      A/O Servo Pulse(F&R D)

      OK

      Arm of the damper servo motor selected in the Active Test operates smoothly.

    6. According to the test result, proceed to the next step.

      Result

      Result Proceed to
      One of the front damper servo motors is malfunctioning A
      All of the front damper servo motors are malfunctioning B
      One of the rear damper servo motors is malfunctioning C
      All of the rear damper servo motors are malfunctioning D
      All of the damper servo motors are normal E

    Result:  2

    B 

    See step  6

    Result:  3

    C 

    See step  8

    Result:  4

    D 

    See step  11

    Result:  6

    E 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [12/2013 - ] 

    Result:  1

    A 

    See step  2

  2. SYSTEM CHECK 
    1. According to the test result, proceed to the next step.

      Result

      Result Proceed to
      Only the No. 1 air conditioning radiator damper servo sub-assembly (air mix) is malfunctioning A
      Only the No. 1 air conditioning radiator damper servo sub-assembly (air outlet) is malfunctioning B
      Only the blower damper servo sub-assembly (air inlet) is malfunctioning C

    Result:  3

    B 

    See step  4

    Result:  4

    C 

    See step  5

    Result:  1

    A 

    See step  3

  3. REPLACE NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (AIR MIX) 
    1. Replace the No. 1 air conditioning radiator damper servo sub-assembly (air mix).

      Refer to DISASSEMBLY [12/2013 - ]

      HINT: 

      Since the servo motor cannot be inspected while it is removed from the vehicle, replace the servo motor with a new or known good one and check that the condition returns to normal.

    2. Check for DTCs.

      Refer to DTC CHECK / CLEAR [12/2013 - ]

      Body Electrical > Air Conditioner > Trouble Codes 

      Result

      Result Proceed to
      DTC B1497 is not output A
      DTC B1497 is output B

    Result:  1

    A 

    END (NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (AIR MIX) WAS DEFECTIVE) 

    Result:  2

    B 

    See step  6

  4. REPLACE NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (AIR OUTLET) 
    1. Replace the No. 1 air conditioning radiator damper servo sub-assembly (air outlet).

      Refer to DISASSEMBLY [12/2013 - ]

      HINT: 

      Since the servo motor cannot be inspected while it is removed from the vehicle, replace the servo motor with a new or known good one and check that the condition returns to normal.

    2. Check for DTCs.

      Refer to DTC CHECK / CLEAR [12/2013 - ]

      Body Electrical > Air Conditioner > Trouble Codes 

      Result

      Result Proceed to
      DTC B1497 is not output A
      DTC B1497 is output B

    Result:  1

    A 

    END (NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (AIR OUTLET) WAS DEFECTIVE) 

    Result:  2

    B 

    See step  6

  5. REPLACE BLOWER DAMPER SERVO SUB-ASSEMBLY (AIR INLET) 
    1. Replace the blower damper servo sub-assembly (air inlet).

      Refer to DISASSEMBLY [12/2013 - ]

      HINT: 

      Since the servo motor cannot be inspected while it is removed from the vehicle, replace the servo motor with a new or known good one and check that the condition returns to normal.

    2. Check for DTCs.

      Refer to DTC CHECK / CLEAR [12/2013 - ]

      Body Electrical > Air Conditioner > Trouble Codes 

      Result

      Result Proceed to
      DTC B1497 is not output A
      DTC B1497 is output B

    Result:  1

    A 

    END (BLOWER DAMPER SERVO SUB-ASSEMBLY (AIR INLET) WAS DEFECTIVE) 

    Result:  2

    B 

    See step  6

  6. REPLACE AIR CONDITIONING HARNESS ASSEMBLY 
    1. Replace the air conditioning harness assembly.

      Refer to DISASSEMBLY [12/2013 - ]

      HINT: 

      Since the air conditioning harness assembly cannot be inspected while it is removed from the vehicle, replace the air conditioning harness assembly with a new or known good one and check that the condition returns to normal.

    2. Check for DTCs.

      Refer to DTC CHECK / CLEAR [12/2013 - ]

      Body Electrical > Air Conditioner > Trouble Codes 

      Result

      Result Proceed to
      DTC B1497 is not output A
      DTC B1497 is output B

    Result:  1

    A 

    END (AIR CONDITIONING HARNESS ASSEMBLY WAS DEFECTIVE) 

    Result:  2

    B 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) 
    1. Disconnect the F80 air conditioning amplifier assembly connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      F80-21 (B) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result:  1

    OK 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [12/2013 - ] 

    Result:  2

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  8. SYSTEM CHECK 
    1. According to the test result, proceed to the next step.

      Result

      Result Proceed to
      Only the rear air mix damper servo sub-assembly is malfunctioning A
      Only the rear mode damper servo sub-assembly is malfunctioning B

    Result:  2

    B 

    See step  10

    Result:  1

    A 

    See step  9

  9. REPLACE REAR AIR MIX DAMPER SERVO SUB-ASSEMBLY 
    1. Replace the rear air mix damper servo sub-assembly.

      Refer to DISASSEMBLY [12/2013 - ]

      HINT: 

      Since the servo motor cannot be inspected while it is removed from the vehicle, replace the servo motor with a new or known good one and check that the condition returns to normal.

    2. Check for DTCs.

      Refer to DTC CHECK / CLEAR [12/2013 - ]

      Body Electrical > Air Conditioner > Trouble Codes 

      Result

      Result Proceed to
      DTC B1497 is not output A
      DTC B1497 is output B

    Result:  1

    A 

    END (REAR AIR MIX DAMPER SERVO SUB-ASSEMBLY WAS DEFECTIVE) 

    Result:  2

    B 

    See step  6

  10. REPLACE REAR MODE DAMPER SERVO SUB-ASSEMBLY 
    1. Replace the rear mode damper servo sub-assembly.

      Refer to DISASSEMBLY [12/2013 - ]

      HINT: 

      Since the servo motor cannot be inspected while it is removed from the vehicle, replace the servo motor with a new or known good one and check that the condition returns to normal.

    2. Check for DTCs.

      Refer to DTC CHECK / CLEAR [12/2013 - ]

      Body Electrical > Air Conditioner > Trouble Codes 

      Result

      Result Proceed to
      DTC B1497 is not output A
      DTC B1497 is output B

    Result:  1

    A 

    END (REAR MODE DAMPER SERVO SUB-ASSEMBLY WAS DEFECTIVE) 

    Result:  2

    B 

    See step  11

  11. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - NO. 2 AIR CONDITIONING HARNESS ASSEMBLY) 
    1. Disconnect the L20 No. 2 air conditioning harness assembly connector.
    2. Disconnect the F81 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
      F81-27 (R BBU) - L20-4 (R BBU) Always Below 1 Ω
      F81-1 (R BUS) - L20-3 (R BUS) Always Below 1 Ω
      F81-25 (R BUG) - L20-2 (R BUG) Always Below 1 Ω
      F81-27 (R BBU) - Body ground Always 10 kΩ or higher
      F81-1 (R BUS) - Body ground Always 10 kΩ or higher
      F81-25 (R BUG) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result:  2

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result:  1

    OK 

    See step  12

  12. REPLACE NO. 2 AIR CONDITIONING HARNESS ASSEMBLY 
    1. Replace the No. 2 air conditioning harness assembly.

      Refer to DISASSEMBLY [12/2013 - ]

      HINT: 

      Since the No. 2 air conditioning harness assembly cannot be inspected while it is removed from the vehicle, replace the No. 2 air conditioning harness assembly with a new or known good one and check that the condition returns to normal.

    2. Check for DTCs.

      Refer to DTC CHECK / CLEAR [12/2013 - ]

      Body Electrical > Air Conditioner > Trouble Codes 

      Result

      Result Proceed to
      DTC B1497 is not output A
      DTC B1497 is output B

    Result:  1

    A 

    END (NO. 2 AIR CONDITIONING HARNESS ASSEMBLY WAS DEFECTIVE) 

    Result:  2

    B 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      F81-28 (+B2) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result:  1

    OK 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [12/2013 - ] 

    Result:  2

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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