AIR CONDITIONING SYSTEM(for Automatic Air Conditioning System with Side-mounted Air Conditioner Pressure Sensor), Diagnostic DTC:B1442

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

DESCRIPTION

The No. 1 blower damper servo sub-assembly 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 air inlet damper to the appropriate position to change the air inlet mode (fresh, recirculation/fresh, and recirculation).

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
B1442 Air Inlet Damper Control Servo Motor Circuit Air inlet damper position sensor value does not change even if air conditioning amplifier assembly operates No. 1 blower damper servo sub-assembly

  • No. 1 blower damper servo sub-assembly

  • No. 1 air conditioning radiator damper servo sub-assembly

  • Air conditioning harness assembly

  • Air conditioning amplifier assembly

  • Blower assembly

Memorized

(30 seconds or more)*

WIRING DIAGRAM

A005Q17E19

CAUTION / NOTICE / HINT

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.

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

    Click here

PROCEDURE


  1. CHECK FOR DTC


    1. Check for DTCs.

      Click here


      Body Electrical > Air Conditioner > Trouble Codes
      Result
      Result Proceed to
      DTC B1497 is output A
      DTC B1441, B1442, B1443 and B1446 are output B
      DTC B1442 is output C

    A

    GO TO DTC B1497 Click here

    B

    REPLACE NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY Click here

    C

  2. INSPECT BLOWER ASSEMBLY


    1. Remove the No. 1 blower damper servo sub-assembly.

      Click here

    2. Operate the air inlet control dampers by hand.

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

    NG

    REPLACE BLOWER ASSEMBLY Click here

    OK

  3. INSPECT AIR CONDITIONING HARNESS ASSEMBLY


    1. Disconnect the No. 1 air conditioning radiator damper servo sub-assembly connector.

    2. Disconnect the No. 1 blower damper servo sub-assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      6 (STE2) - 3 (sigB) Always Below 1 Ω
      5 (STE1) - 2 (sigA) Always Below 1 Ω
      8 (M-) - 5 (M-) Always Below 1 Ω
      7 (M+) - 4 (M+) Always Below 1 Ω
      4 (GND) - 1 (GND) Always Below 1 Ω
      6 (STE2) or 3 (sigB) - Body ground Always 10 kΩ or higher
      5 (STE1) or 2 (sigA) - Body ground Always 10 kΩ or higher
      8 (M-) or 5 (M-) - Body ground Always 10 kΩ or higher
      7 (M+) or 4 (M+) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE AIR CONDITIONING HARNESS ASSEMBLY Click here

    OK

  4. PERFORM ACTIVE TEST USING GTS (AIR INLET DAMPER TARG PULSE)


    1. Reconnect the No. 1 air conditioning radiator damper servo sub-assembly connector.

    2. Reconnect the No. 1 blower damper servo sub-assembly connector.

    3. Connect the GTS to the DLC3.

    4. Turn the ignition switch to ON.

    5. Turn the GTS on.

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

    7. Perform the Active Test according to the display on the GTS.


      Body Electrical > Air Conditioner > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Air Inlet Damper Targ Pulse No. 1 blower damper servo sub-assembly pulse

      Min.: 128

      Max.: 383

      		 Operates between 220 to 256 pulses

      Body Electrical > Air Conditioner > Active Test
      Tester Display
      Air Inlet Damper Targ Pulse
      OK
      No. 1 blower damper servo sub-assembly pulse operates smoothly.
      Result
      Result Proceed to
      No. 1 blower damper servo sub-assembly pulse are malfunctioning A
      No. 1 blower damper servo sub-assembly pulse is normal B

    B

    INSPECT NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY Click here

    A

  5. CHECK HARNESS AND CONNECTOR (NO. 1 BLOWER DAMPER SERVO SUB-ASSEMBLY - BODY GROUND)


    1. Disconnect the No. 1 blower damper servo sub-assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY Click here

    OK

  6. INSPECT NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY


    1. Measure the voltage according to the value(s) in the table below.

      Tester Connection Condition Specified Condition
      4 (M+) - Body ground

      • Ignition switch ON

      • No. 1 blower damper servo sub-assembly operating (fresh)

      		 11 to 14 V ←→ Below 1 V
      5 (M-) - Body ground

      • Ignition switch ON

      • No. 1 blower damper servo sub-assembly operating (recirculation)

      		 11 to 14 V ←→ Below 1 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NO. 1 BLOWER DAMPER SERVO SUB-ASSEMBLY Click here

    NG

    REPLACE NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY Click here

  7. INSPECT NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY


    1. A005OWLC06
      *a

      Component with harness connected

      (No. 1 Blower Damper Servo Sub-assembly)

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      2 (sigA) - Body ground Ignition switch ON 4.75 V to 5.25 V
      3 (sigB) - Body ground Ignition switch ON 4.75 V to 5.25 V
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY Click here

    OK

  8. INSPECT NO. 1 BLOWER DAMPER SERVO SUB-ASSEMBLY


    1. Turn the ignition switch ON.

    2. A005OCTC01
      *a

      Component with harness connected

      (No. 1 blower damper servo sub-assembly)
      *b Fresh wave form
      *c Recirculation wave form

      Connect an oscilloscope to terminals 2 (sig A) and 3 (sig B) of the air conditioning amplifier assembly and check the waveform.

      OK
      Waveform is similar to that shown in the illustration.
      Item Content
      Tool Setting 2.5 V/DIV., 200 ms./DIV.
      Vehicle Condition

      • Ignition switch ON

      • No. 1 blower damper servo sub-assembly operating
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY Click here

    NG

    REPLACE NO. 1 BLOWER DAMPER SERVO SUB-ASSEMBLY Click here