AIR CONDITIONING SYSTEM, Diagnostic DTC:B1446/46

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

DESCRIPTION

The No. 3 air conditioning radiator damper servo sub-assembly (air mix servo motor 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 air mix servo motor to any position. As a result, the air mix servo motor varies the mixture of hot air from the heater core and cold air from the evaporator so that the temperature of the air blowing toward the driver side is as requested.

Tech Tips

Confirm that no mechanical problem is present because this trouble code may be stored when either a damper link or damper is mechanically locked.

DTC No. DTC Detection Condition Trouble Area
B1446/46 The air mix damper position does not change when the air conditioning amplifier assembly operates the No. 3 air conditioning radiator damper servo sub-assembly (air mix servo motor for driver side).

  • No. 3 air conditioning radiator damper servo sub-assembly (air mix servo motor for driver side)

  • Air conditioning harness assembly

  • Air conditioning amplifier assembly

WIRING DIAGRAM

A01UZSDE12

PROCEDURE


  1. READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON (IG).

    3. Turn the GTS on.

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

    5. According to the display on the GTS, read the Data List.

      Air Conditioner
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Air Mix Servo Targ Pulse (D)

      Air mix servo motor target pulse (driver side) /

      Min.: 0

      Max.: 255

      • MAX COOL: 4 (pulse)

      • MAX HOT: 93 (pulse)

      		 -
      Air Mix Servo Actual Pulse (D)

      Air mix servo motor actual pulse (driver side) /

      Min.: 0

      Max.: 255

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

    B

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

    C

    PERFORM ACTIVE TEST USING GTS Click here

    A

  2. CHECK FOR DTC


    1. Clear the DTCs Click here.

    2. Check for DTCs Click here.

      OK
      DTC B1446/46 is not output

    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

  3. PERFORM ACTIVE TEST USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON (IG).

    3. Turn the GTS on.

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

    5. According to the display on the GTS, perform the Active Test.

      Air Conditioner
      Tester Display Test Part Control Range Diagnostic Note
      Air Mix Servo Targ Pulse (D) Air mix servo motor pulse (driver side) Min.: 0, Max.: 255 Perform Active Test when value between 4 and 93 displayed
      OK
      No. 3 air conditioning radiator damper servo sub-assembly (air mix servo motor for driver side) operates normally.

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

  4. REPLACE NO. 3 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (AIR MIX SERVO MOTOR FOR DRIVER SIDE)


    1. Replace the No. 3 air conditioning radiator damper servo sub-assembly (air mix 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 a known good one and check that the condition returns to normal.

    2. Check for the DTC Click here.

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

    A

    END (NO. 3 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (AIR MIX SERVO MOTOR FOR DRIVER SIDE) WAS DEFECTIVE)

    B

  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 a known good one and check that the condition returns to normal.

    2. Check for the DTC Click here.

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

    A

    END (AIR CONDITIONING HARNESS ASSEMBLY WAS DEFECTIVE)

    B

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here