AIR CONDITIONING SYSTEM, Diagnostic DTC:B1446

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

DESCRIPTION


The No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 (driver side upper air mix) 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 these signals to move the No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 (driver side upper air mix) to the appropriate 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 air conditioning amplifier assembly communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness assembly.

DTC No. Detection Item DTC Detection Condition Trouble Area Memory
B1446 Air Mix Damper Control Servo Motor Circuit (Driver Side)

  • Diagnosis condition: No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 (driver side upper air mix) operation

  • Malfunction status: The damper servo operation request signal is output but the position information of the servo does not change or servo is malfunctioning

  • Detection time: Continuously for 30 seconds or more

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

  • No. 4 air conditioning radiator damper servo sub-assembly*2 (driver side upper air mix)

  • Air conditioning harness assembly

  • Air conditioning amplifier assembly

 Memorized
DTC Detection Condition Combination Table
Vehicle Condition
Pattern 1 Pattern 2
Diagnosis Condition No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 (driver side upper air mix) operation ○ ○
Malfunction Status The damper servo operation request signal is output but the position information of the servo does not change ○ -
The damper servo operation request signal is output but the position information of the servo is malfunctioning - ○
Detection Time Continuously for 30 seconds or more Continuously for 30 seconds or more
Trip Count 1 trip 1 trip

Tech Tips

If the conditions match either of these patterns, a DTC will be output.

WIRING DIAGRAM


  1. for LHD:

    Figure 1. for 4 Zone Type:

    B006AWLE49

    Figure 2. for Dual Type:

    B006AWLE78

  2. for RHD:

    Figure 3. for 4 Zone Type:

    B006AWLE79

    Figure 4. for Dual Type:

    B006AWLE80

CAUTION / NOTICE / HINT

Note


  • 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.

  • When installing the damper servo motor, make sure to install it correctly.

  • When the servo motor is replaced, be sure to perform servo motor initialization.

    Click here

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. CHECK FOR DTC


    1. Check for DTCs.

      Click here


      Body Electrical > Air Conditioner > Trouble Codes
      Result
      Result Proceed to
      DTC B1446 is output A
      DTC B1446 and B1497 are output. B

    B

    GO TO DTC B1497 Click here

    A

  2. CHECK AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY


    1. Check for No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 is installed correctly.

      OK
      No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 is installed correctly.

      • *1: for LHD (for 4 Zone Type)

      • *2: for LHD (for Dual Type), for RHD

      Result
      Result Proceed to
      OK A
      NG (for LHD (for 4 Zone Type)) B
      NG (for LHD (for Dual Type), for RHD) C

    B

    REINSTALL NO. 2 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY Click here

    C

    REINSTALL NO. 4 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY Click here

    A

  3. CHECK AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (MOTOR, LINK, DAMPER)


    1. Check for a wire harness caught between the links of the motors and dampers.

      OK
      No wire harnesses are caught between the links of the motors and dampers.
      Result
      Proceed to
      OK
      NG

    NG

    REMOVE PINCHED WIRE HARNESS

    OK

  4. CHECK AIR CONDITIONING RADIATOR ASSEMBLY (DAMPER)


    1. Remove the No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2.

      Click here


      • *1: for LHD (for 4 Zone Type)

      • *2: for LHD (for Dual Type), for RHD

    2. Operate the dampers by hand.

      OK
      The dampers are easily operated by hand.
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE AIR CONDITIONING RADIATOR ASSEMBLY

    OK

  5. PERFORM ACTIVE TEST USING GTS (COOL A/M SERVO PULSE(D))


    • *1: for LHD (for 4 Zone Type)

    • *2: for LHD (for Dual Type), for RHD

    • *3: Actually operates the No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2.


    1. Remove the No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2.

      Click here

    2. Connect the No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 (driver side lower side air mix) connector to No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 (driver side upper side air mix).

    3. Connect the GTS to the DLC3.

    4. Turn the engine switch on (IG).

    5. Turn the GTS on.

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

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


      Body Electrical > Air Conditioner > Active Test
      Tester Display Measurement Item Control Range Restrict Condition
      Cool A/M Servo Pulse(D)

        for LHD:

      • No. 2 air conditioning radiator damper servo sub-assembly (driver side lower air mix) operation (for 4 Zone Type)*3

      • No. 4 air conditioning radiator damper servo sub-assembly (driver side lower air mix) operation (for Dual Type)*3


        for RHD:

      • No. 4 air conditioning radiator damper servo sub-assembly (driver side lower air mix) operation*3

      Min.: 128

      Max.: 383

        for LHD:

      • Operates between 254 and 358 pulses


        for RHD:

      • Operates between 154 to 258 pulses

      Body Electrical > Air Conditioner > Active Test
      Tester Display
      Cool A/M Servo Pulse(D)
      OK
      No. 2 air conditioning radiator damper servo sub-assembly*1 or No. 4 air conditioning radiator damper servo sub-assembly*2 (driver side upper air mix) is operated.
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE AIR CONDITIONING HARNESS ASSEMBLY Click here

    NG

  6. CHECK AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY


    1. Interchange the driver side upper air mix servo motor with driver side lower air mix servo motor and connect the connectors to them.

      Click here

    2. Clear the DTCs.

      Click here

    3. Check for DTCs.

      Click here

      Result
      Result Proceed to
      DTC B1453 is output (for LHD (for 4 Zone Type)) A
      DTC B1453 is output (for LHD (for Dual Type), for RHD) B
      DTC B1446 is output C
      DTCs are not output D

      Tech Tips

      Codes other than DTC B1446 and B1453 may be output at this time, but they are not related to this check.


    A

    REPLACE NO. 2 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY Click here

    B

    REPLACE NO. 4 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY Click here

    C

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    D

    USE SIMULATION METHOD TO CHECK Click here