AIR CONDITIONING SYSTEM, Diagnostic DTC:B1446/46

DTC Code DTC Name
B1446/46 Air Mix Damper Control Servo Motor Circuit (Driver Side)

DESCRIPTION

1. for LHD

The No. 2 air conditioning radiator damper servo sub-assembly (air mix for driver side) sends pulse signals to inform the air conditioning amplifier assembly of the damper position. The air conditioning amplifier assembly activates the motor (normal or reverse) based on the signals to move the No. 2 air conditioning radiator damper servo sub-assembly (air mix for driver side) to any position. As a result, the amount of air passing through the heater core after passing through the evaporator is adjusted, and the temperature of the air blowing toward the driver seat side is controlled.

The air conditioning amplifier assembly communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness assembly.

Tech Tips

Confirm that no mechanical problem is present because this diagnostic code can be output when either a damper link or the damper is mechanically locked.

2. for RHD

The No. 1 air conditioning radiator damper servo sub-assembly (air mix for driver side) sends pulse signals to inform the air conditioning amplifier assembly of the damper position. The air conditioning amplifier assembly activates the motor (normal or reverse) based on the signals to move the No. 1 air conditioning radiator damper servo sub-assembly (air mix for driver side) to any position. As a result, the amount of air passing through the heater core after passing through the evaporator is adjusted, and the temperature of the air blowing toward the driver seat side is controlled.

The air conditioning amplifier assembly communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness assembly.

Tech Tips

Confirm that no mechanical problem is present because this diagnostic code can be output when either a damper link or the damper is mechanically locked.

DTC No. DTC Detection Condition Trouble Area
B1446/46

for LHD:

Air mix damper position sensor value does not change even if air conditioning amplifier assembly operates No. 2 air conditioning radiator damper servo sub-assembly (air mix for driver side)

for RHD:

Air mix damper position sensor value does not change even if air conditioning amplifier assembly operates No. 1 air conditioning radiator damper servo sub-assembly (air mix for driver side)

  • No. 2 air conditioning radiator damper servo sub-assembly (air mix for driver side)*1

  • No. 1 air conditioning radiator damper servo sub-assembly (air mix for driver side)*2

  • Air conditioning harness assembly

  • Air conditioning amplifier assembly

WIRING DIAGRAM

A01EYGAE19

INSPECTION PROCEDURE

PROCEDURE


  1. CONFIRM MODEL

    Result
    Result Proceed to
    for LHD A
    for RHD B

    B

    READ VALUE USING INTELLIGENT TESTER Click here

    A

  2. READ VALUE USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the intelligent tester on.

    4. Operate the driver side temperature adjustment switch.

    5. Enter the following menus: Body / Air Conditioner / Data List.

    6. Check the value(s) by referring to the table below.

      Air Conditioner
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Air Mix Servo Actual Pulse(D) No. 2 air conditioning radiator damper servo sub-assembly (air mix for driver side) actual pulse / Min.: 0, Max.: 255

      MAX COLD: 5 (pulse)

      MAX HOT: 103 (pulse)

      		 -
      OK
      The display is as specified in the normal condition column.
      Result
      Result Proceed to
      NG A
      OK (When troubleshooting according to Problem Symptoms Table) B
      OK (When troubleshooting according to the DTC) C

    B

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    C

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    A

  3. PERFORM ACTIVE TEST USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the intelligent tester on.

    4. Enter the following menus: Body / Air Conditioner / Active Test.

    5. Check the operation by referring to the table below.

      Air Conditioner
      Tester Display Test Part Control Range Diagnostic Note
      Air Mix Servo Targ Pulse(D) No. 2 air conditioning radiator damper servo sub-assembly (air mix for driver side) pulse Min.: 0, Max.: 255 Operates between 5 and 103 pulses
      OK
      Air temperature changes in accordance with each control range.

    NG

    REPLACE NO. 2 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (AIR MIX FOR DRIVER SIDE) Click here

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

  4. REPLACE NO. 2 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (AIR MIX FOR DRIVER SIDE)


    1. Replace the No. 2 air conditioning radiator damper servo sub-assembly (air mix for driver side) Click here.

      Tech Tips

      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 the DTC.

      Result
      Result Proceed to
      DTC B1446/46 is output A
      DTC B1446/46 is not output B

    B

    END (NO. 2 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (AIR MIX FOR DRIVER SIDE) WAS DEFECTIVE)

    A

  5. REPLACE AIR CONDITIONING HARNESS ASSEMBLY


    1. Replace the air conditioning harness assembly Click here.

      Tech Tips

      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 the DTC.

      Result
      Result Proceed to
      DTC B1446/46 is output A
      DTC B1446/46 is not output B

    B

    END (AIR CONDITIONING HARNESS ASSEMBLY WAS DEFECTIVE)

    A

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

  6. READ VALUE USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the intelligent tester on.

    4. Operate the driver side temperature adjustment switch.

    5. Enter the following menus: Body / Air Conditioner / Data List.

    6. Check the value(s) by referring to the table below.

      Air Conditioner
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Air Mix Servo Actual Pulse(D) No. 1 air conditioning radiator damper servo sub-assembly (air mix for driver side) actual pulse / Min.: 0, Max.: 255

      MAX COLD: 105

      MAX HOT: 7

      		 -
      OK
      The display is as specified in the normal condition column.
      Result
      Result Proceed to
      NG A
      OK (When troubleshooting according to Problem Symptoms Table) B
      OK (When troubleshooting according to the DTC) C

    B

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    C

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    A

  7. PERFORM ACTIVE TEST USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the intelligent tester on.

    4. Enter the following menus: Body / Air Conditioner / Active Test.

    5. Check the operation by referring to the table below.

      Air Conditioner
      Tester Display Test Part Control Range Diagnostic Note
      Air Mix Servo Targ Pulse(D) No. 1 air conditioning radiator damper servo sub-assembly (air mix for driver side) pulse Min.: 0, Max.: 255 Operates between 7 and 105 pulses
      OK
      Air temperature changes in accordance with each control range.

    NG

    REPLACE NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (AIR MIX FOR DRIVER SIDE) Click here

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

  8. REPLACE NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (AIR MIX FOR DRIVER SIDE)


    1. Replace the No. 1 air conditioning radiator damper servo sub-assembly (air mix for driver side) Click here.

      Tech Tips

      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 the DTC.

      Result
      Result Proceed to
      DTC B1446/46 is output A
      DTC B1446/46 is not output B

    B

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

    A

  9. REPLACE AIR CONDITIONING HARNESS ASSEMBLY


    1. Replace the air conditioning harness assembly Click here.

      Tech Tips

      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 the DTC.

      Result
      Result Proceed to
      DTC B1446/46 is output A
      DTC B1446/46 is not output B

    B

    END (AIR CONDITIONING HARNESS ASSEMBLY WAS DEFECTIVE)

    A

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here