AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System), Diagnostic DTC:B1447/47

DTC Code DTC Name
B1447/47 Rear Air Mix Damper Control Servo Motor Circuit

DESCRIPTION

The rear air mix control servo motor sends pulse signals to indicate the damper position to the air conditioning amplifier. The air conditioning amplifier activates the motor (normal or reverse) based on these signals to move the rear air mix damper to the appropriate position. This adjusts the amount of air passing through the heater core after passing the evaporator and controls the temperature of the blown air.

Tech Tips

Confirm that there are no mechanical problems because this DTC can be set if either a damper link or damper is mechanically locked.

DTC No. DTC Detection Condition Trouble Area
B1447/47 Rear air mix damper position does not change even if air conditioning amplifier operates rear air mix control servo motor

  • Rear air mix control servo motor

  • Rear air conditioning harness

  • Wire harness between rear air conditioning harness and air conditioning amplifier

  • Air conditioning amplifier

WIRING DIAGRAM

A017ELPE12

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (AIR MIX PULSE-R)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch on (IG) and turn the intelligent tester main switch on.

    3. Select the item below in the Data List, and read the value displayed on the intelligent tester.

      Data List / Air Conditioner:
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Air Mix Pulse-R

      Rear air mix control servo motor target pulse /

      Min.: 0, Max.: 255

      • LHD:

        MAX COLD: 9 (pulse)

        MAX HOT: 54 (pulse)


      • RHD:

        MAX COLD: 9 (pulse)

        MAX HOT: 54 (pulse)

      		 -
      OK
      The display is as specified in the normal condition column.
      Result
      Result Proceed to
      NG A
      OK (Checking from PROBLEM SYMPTOMS TABLE) B
      OK (Checking from DTC) C

    B

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

    C

    REPLACE AIR CONDITIONING AMPLIFIER Click here

    A

  2. CHECK HARNESS AND CONNECTOR (REAR AIR CONDITIONING HARNESS - AIR CONDITIONING AMPLIFIER)


    1. A017B7BE08

      Disconnect the N11 rear air conditioning harness connector.

    2. Disconnect the D34 amplifier connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      N11-2 (RBUG) - D34-1 (RBUG) Always Below 1 Ω
      N11-3 (RBUS) - D34-23 (RBUS) Always Below 1 Ω
      N11-4 (RBBU) - D34-21 (RBBU) Always Below 1 Ω
      D34-1 (RBUG) - Body ground Always 10 kΩ or higher
      D34-23 (RBUS) - Body ground Always 10 kΩ or higher
      D34-21 (RBBU) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. REPLACE REAR AIR MIX CONTROL SERVO MOTOR


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


    NEXT

  4. CHECK DTC OUTPUT


    1. Clear the DTC Click here.

    2. Check for DTC Click here.

      OK
      DTC B1447/47 is not output.

    NG

    REPAIR OR REPLACE REAR AIR CONDITIONING HARNESS

    OK

    END (REAR AIR MIX CONTROL SERVO MOTOR IS DEFECTIVE)