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 A/C amplifier. The A/C amplifier activates the motor (normal or reverse) based on these signals to move the rear air mix damper 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 rear is controlled.

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

Tech Tips

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

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

  • Rear air mix control servo motor

  • Rear air conditioning harness

  • Harness or connector between rear air conditioning harness and A/C amplifier

  • A/C amplifier

WIRING DIAGRAM

A01CGIPE19

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the intelligent tester on.

    4. Operate the rear side temperature adjustment switch.

    5. Enter the following menus: Body / 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 (R) Rear air mix servo motor target pulse / Min.: 0, Max.: 255

      MAX. COLD: 21 (pulse)

      MAX. HOT: 66 (pulse)

      		 -
      Air Mix Servo Actual Pulse (R) Rear air mix servo motor actual pulse / Min.: 0, Max.: 255

      MAX. COLD: 21 (pulse)

      MAX. HOT: 66 (pulse)

      		 -
      OK
      The display is as specified in the Normal Condition column.
      Result
      Result Proceed to
      NG A
      OK (When troubleshooting according to Problem Symptoms Table) B
      OK (When troubleshooting according to the DTC) C

    B

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

    C

    REPLACE A/C AMPLIFIER Click here

    A

  2. PERFORM ACTIVE TEST USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the intelligent tester on.

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

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

      Air Conditioner
      Tester Display Test Part Control Range Diagnostic Note
      Rear Air Mix Servo Targ Pulse Rear air mix servo motor pulse Min.: 0, Max.: 255 -
      OK
      Air temperature changes in accordance with each control range.

    NG

    CHECK HARNESS AND CONNECTOR (REAR AIR CONDITIONING HARNESS - A/C AMPLIFIER) Click here

    OK

    REPLACE A/C AMPLIFIER Click here

  3. CHECK HARNESS AND CONNECTOR (REAR AIR CONDITIONING HARNESS - A/C AMPLIFIER)


    1. A01CBT8E05

      Disconnect the rear air conditioning harness connector.

    2. A01CBOZE31

      Disconnect the A/C amplifier connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      M19-3 (RBUS) - G34-1 (RBUS) Always Below 1 Ω
      M19-4 (RBBU) - G34-23 (RBBU) Always Below 1 Ω
      M19-2 (RBUG) - G34-21 (RBUG) Always Below 1 Ω
      G34-1 (RBUS) - Body ground Always 10 kΩ or higher
      G34-23 (RBBU) - Body ground Always 10 kΩ or higher
      G34-21 (RBUG) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT REAR AIR MIX CONTROL SERVO MOTOR


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

      Tech Tips

      Since the rear air mix control servo motor cannot be inspected while it is removed from the vehicle, replace the rear air mix control servo motor with a new or a known good one and check that the condition returns to normal.

    2. Check for the DTC.

      Result
      Result Proceed to
      DTC B1447/47 is output A
      DTC B1447/47 is not output B

    B

    REPLACE REAR AIR MIX CONTROL SERVO MOTOR Click here

    A

  5. INSPECT REAR AIR CONDITIONING HARNESS


    1. Replace the rear air conditioning harness Click here.

      Tech Tips

      Since the rear air conditioning harness cannot be inspected while it is removed from the vehicle, replace the rear air conditioning harness with a new or a known good one and check that the condition returns to normal.

    2. Check for the DTC.

      Result
      Result Proceed to
      DTC B1447/47 is output A
      DTC B1447/47 is not output B

    B

    REPLACE REAR AIR CONDITIONING HARNESS Click here

    A

    REPLACE A/C AMPLIFIER Click here