AIR CONDITIONING SYSTEM, Diagnostic DTC:B1449

DTC Code DTC Name
B1449 Air Outlet Damper Control Servo Motor Circuit (Rear)

DESCRIPTION


The No. 1 rear cooling unit damper servo sub-assembly (MODE LH)*1 or No. 1 rear cooling unit damper servo sub-assembly (MODE RH)*2 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. 1 rear cooling unit damper servo sub-assembly (MODE LH)*1 or No. 1 rear cooling unit damper servo sub-assembly (MODE RH)*2 to the appropriate position, which controls the air outlet switching.

DTC No. Detection Item DTC Detection Condition Trouble Area Memory
B1449 Air Outlet Damper Control Servo Motor Circuit (Rear)

  • Diagnosis condition: During No. 1 rear cooling unit damper servo sub-assembly (MODE LH)*1 or No. 1 rear cooling unit damper servo sub-assembly (MODE RH)*2 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. 1 rear cooling unit damper servo sub-assembly (MODE LH)*1

  • No. 1 rear cooling unit damper servo sub-assembly (MODE RH)*2

  • Air conditioning harness assembly

  • Air conditioning amplifier assembly

 Memorized
DTC Diagnosis Condition Combination Table
Vehicle Condition
Pattern 1 Pattern 2
Diagnosis Condition During No. 1 rear cooling unit damper servo sub-assembly (MODE LH)*1 or No. 1 rear cooling unit damper servo sub-assembly (MODE RH)*2 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

Figure 1. for LHD:

B006AC0E23

Figure 2. for RHD:

B006AC0E22

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 B1448 is output A
      DTC B1448 and B149A are output. B

    B

    GO TO DTC B149A Click here

    A

  2. CHECK NO. 1 REAR COOLING UNIT DAMPER SERVO SUB-ASSEMBLY


    1. Check for No. 1 rear cooling unit damper servo sub-assembly is installed correctly.

      OK
      No. 1 rear cooling unit damper servo sub-assembly is installed correctly.
      Result
      Proceed to
      OK
      NG

    NG

    REINSTALL NO. 1 REAR COOLING DAMPER SERVO SUB-ASSEMBLY Click here

    OK

  3. CHECK NO. 1 REAR COOLING 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 REAR COOLING UNIT ASSEMBLY (DAMPER)


    1. Remove the No. 1 rear cooling unit damper servo sub-assembly.

      Click here

    2. Operate the dampers by hand.

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

    NG

    REPAIR OR REPLACE REAR COOLING UNIT ASSEMBLY

    OK

  5. CHECK HARNESS AND CONNECTOR (NO. 2 AIR CONDITIONING HARNESS ASSEMBLY - AIR CONDITIONING AMPLIFIER ASSEMBLY)


    1. Disconnect the L134 No. 2 air conditioning harness assembly connector.

    2. Disconnect the G63 air conditioning amplifier assembly connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      L134-12 (BRRG) - G63-2 (RBUG) Always Below 1 Ω
      L134-11 (BURR) - G63-22 (RBUS) Always Below 1 Ω
      L134-10 (BRRB) - G63-3 (RBBU) Always Below 1 Ω
      L134-12 (BRRG) or G63-2 (RBUG) - Other terminals and body ground Always 10 kΩ or higher
      L134-11 (BURR) or G63-22 (RBUS) - Other terminals and body ground Always 10 kΩ or higher
      L134-10 (BRRB) or G63-3 (RBBU) - Other terminals and body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. PERFORM ACTIVE TEST USING GTS (FOOT A/O SERVO PULSE(D))


    • *1: for LHD

    • *2: for RHD

    • *3: Actually operates the No. 1 rear cooling unit damper servo sub-assembly (MODE LH)*1 or No. 1 rear cooling unit damper servo sub-assembly (MODE RH)*2.


    1. Remove the No. 1 rear cooling unit damper servo sub-assembly.

      Click here

    2. for LHD:


      1. Connect the No. 1 rear cooling unit damper servo sub-assembly (MODE LH) connector to No. 1 rear cooling unit damper servo sub-assembly (MODE rH).

    3. for RHD:


      1. Connect the No. 1 rear cooling unit damper servo sub-assembly (MODE RH) connector to No. 1 rear cooling unit damper servo sub-assembly (MODE LH).

    4. Connect the GTS to the DLC3.

    5. Turn the engine switch on (IG).

    6. Turn the GTS on.

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

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


      Body Electrical > Air Conditioner > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      A/O Servo Pulse(Rr P)

        for LHD:

      • No. 1 rear cooling unit damper servo sub-assembly (MODE RH) operation*3


        for RHD:

      • No. 1 rear cooling unit damper servo sub-assembly (MODE LH) operation*3

      Min.: 128

      Max.: 383

        for LHD:

      • Operates between 237 and 275 pulses


        for RHD:

      • Operates between 234 and 278 pulses

      Body Electrical > Air Conditioner > Active Test
      Tester Display
      A/O Servo Pulse(Rr P)
      OK
      No. 1 rear cooling unit damper servo sub-assembly (MODE LH)*1 or No. 1 rear cooling unit damper servo sub-assembly (MODE RH)*2 is operated.
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NO. 2 AIR CONDITIONING HARNESS ASSEMBLY Click here

    NG

  7. CHECK NO. 1 REAR COOLING DAMPER SERVO SUB-ASSEMBLY


    1. Interchange the MODE LH servo motor with MODE RH 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 B1489 is output A
      DTC B1449 is output B
      DTCs are not output C

      Tech Tips

      Codes other than DTC B1449 and B1489 may be output at this time, but they are not related to this check.


    A

    REPLACE NO. 1 REAR COOLING DAMPER SERVO SUB-ASSEMBLY Click here

    B

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    C

    USE SIMULATION METHOD TO CHECK Click here