AIR CONDITIONING SYSTEM, Diagnostic DTC:B1446/46

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

DESCRIPTION

The air mix damper servo sends pulse signals to inform the A/C amplifier of the damper position. The A/C amplifier activates the motor (normal, reverse) based on the signals to move the air mix damper (driver seat) 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 A/C amplifier communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness.

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 Air mix damper position sensor value does not change even if A/C amplifier operates air mix control servo motor

  • Air mix control servo motor

  • Air conditioning harness

  • A/C amplifier

WIRING DIAGRAM

A01616FE05

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the intelligent tester on.

    4. Operate the driver side temperature adjustment switch.

    5. Select the item below in the Data List, and read the display on the intelligent tester.

      Data List / Air Conditioner
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note

      Air Mix Servo Targ Pulse(D)

      (Air Mix Pulse-D)

      		 Driver side air mix servo motor target pulse / Min.: 0, Max.: 255

      LHD:

      MAX COLD: 5 (pulse)

      MAX HOT: 104 (pulse)

      RHD:

      MAX COLD: 105 (pulse)

      MAX HOT: 6 (pulse)

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

    B

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    C

    REPLACE A/C AMPLIFIER Click here

    A

  2. INSPECT AIR MIX CONTROL SERVO MOTOR


    1. Replace the air mix control servo motor Click here.

      Tech Tips

      Since the servo motor cannot be inspected while it is removed from the vehicle, replace the servo motor with a 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

    REPLACE AIR MIX CONTROL SERVO MOTOR Click here

    A

  3. INSPECT AIR CONDITIONING HARNESS


    1. Replace the air conditioning harness Click here.

      Tech Tips

      Since the air conditioning harness cannot be inspected while it is removed from the vehicle, replace the air conditioning harness with a 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

    REPLACE AIR CONDITIONING HARNESS Click here

    A

    REPLACE A/C AMPLIFIER Click here