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 control servo motor (for driver side) sends pulse signals to indicate the damper position to the A/C amplifier. The A/C amplifier activates the motor (normal or reverse) based on these signals to move the air mix damper (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 side is controlled.

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

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 (for driver side)

  • Air mix control servo motor (for driver side)

  • Air conditioning harness

  • A/C amplifier

WIRING DIAGRAM

A01EJNDE08

INSPECTION PROCEDURE

Tech Tips

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

PROCEDURE


  1. READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Operate the driver side temperature adjustment switch.

    5. Enter the following menus: Body Electrical / 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 Targ Pulse(D) Air mix control servo motor (for driver side) target pulse / Min.: 0, Max.: 255

      MAX. COLD: 5 (pulse)

      MAX. HOT: 103 (pulse)

      		 -
      Air Mix Servo Actual Pulse(D) Air mix control servo motor (for driver side) actual pulse / Min.: 0, Max.: 255

      MAX. COLD: 5 (pulse)

      MAX. HOT: 103 (pulse)

      		 -
      OK
      When the driver side temperature adjustment switch is turned from MAX COLD to MAX HOT, the actual pulse changes following the target pulse.
      Result
      Result Proceed to
      Target pulse changes but actual pulse dose not change A
      Target pulse and actual pulse do not change B
      Actual pulse changes following the target pulse (When troubleshooting according to the DTC) C
      Actual pulse changes following the target pulse (When troubleshooting according to the DTC) D

    B

    REPLACE AIR MIX CONTROL SERVO MOTOR (FOR DRIVER SIDE) Click here

    C

    RECHECK FOR DTC Click here

    D

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

    A

    REPLACE A/C AMPLIFIER Click here

  2. REPLACE AIR MIX CONTROL SERVO MOTOR (FOR DRIVER SIDE)


    1. Replace the air mix control servo motor (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 DTCs.

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

    B

    END (AIR MIX CONTROL SERVO MOTOR (FOR DRIVER SIDE) WAS DEFECTIVE)

    A

  3. REPLACE 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 new or known good one and check that the condition returns to normal.

    2. Check for DTCs.

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

    B

    END (AIR CONDITIONING HARNESS WAS DEFECTIVE)

    A

    REPLACE A/C AMPLIFIER Click here

  4. RECHECK FOR DTC


    1. Clear the DTCs.

    2. Check for DTCs.

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

    B

    USE SIMULATION METHOD TO CHECK Click here

    A

    REPLACE A/C AMPLIFIER Click here