AIR CONDITIONING SYSTEM, Diagnostic DTC:B1442/42

DTC Code DTC Name
B1442/42 Air Inlet Damper Control Servo Motor Circuit

DESCRIPTION

The air inlet 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 air inlet mode selection air inlet control damper to any position, which controls the intake air settings (FRESH, FRESH/RECIRCULATION, and RECIRCULATION).

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

Tech Tips

Confirm that no mechanical problem is present because this DTC can be stored when either a damper link or the damper is mechanically locked.

DTC No. DTC Detection Condition Trouble Area
B1442/42 Air inlet damper position sensor value does not change even if A/C amplifier operates air inlet control servo motor

  • Air inlet control servo motor

  • Air conditioning harness

  • A/C amplifier

WIRING DIAGRAM

A01NE4QE21

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the intelligent tester on.

    4. Operate the R/F (Recirculation/Fresh) 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 Inlet Damper Targ Pulse Air inlet servo motor target pulse / Min.: 0, Max.: 255

      RECIRCULATION: 7 (pulse)

      FRESH: 28 (pulse)

      		 -
      Air Inlet Damper Actual Pulse Air inlet servo motor actual pulse / Min.: 0, Max.: 255

      RECIRCULATION: 7 (pulse)

      FRESH: 28 (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 power 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
      Air Inlet Damper Targ Pulse Air inlet damper target pulse Min.: 0, Max.: 255 -
      OK
      Recirculation damper position changes in accordance with each control range.

    NG

    INSPECT AIR INLET CONTROL SERVO MOTOR Click here

    OK

    REPLACE A/C AMPLIFIER Click here

  3. INSPECT AIR INLET CONTROL SERVO MOTOR


    1. Replace the air inlet control servo motor 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.

      Result
      Result Proceed to
      DTC B1442/42 is output A
      DTC B1442/42 is not output B

    B

    END (AIR INLET CONTROL SERVO MOTOR WAS DEFECTIVE)

    A

  4. INSPECT AIR CONDITIONING HARNESS


    1. Replace the air conditioning harness Click here.

      Tech Tips

      Since the air conditioning harness cannot be inspected while it is removed from the vehicle, replace the 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 B1442/42 is output A
      DTC B1442/42 is not output B

    B

    END (AIR CONDITIONING HARNESS WAS DEFECTIVE)

    A

    REPLACE A/C AMPLIFIER Click here