Toyota Avalon Service & Repair Manual: Air Mix Damper Control Servo Motor Circuit (Passenger Side) (B1441,B1443,B1446)

Toyota Avalon Service & Repair Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System(for Gasoline Model) / Air Mix Damper Control Servo Motor Circuit (Passenger Side) (B1441,B1443,B1446)

DESCRIPTION

  • B1441: The No. 1 air conditioning radiator damper servo sub-assembly (front passenger side air mix) 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 air conditioning radiator damper servo sub-assembly (front passenger side air mix) 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 output air. The air conditioning amplifier assembly communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness assembly.
  • B1443: The No. 1 air conditioning radiator damper servo sub-assembly (mode) 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 outlet damper to the appropriate position, which controls the air outlet switching. The air conditioning amplifier assembly communicates with the servo through a communication/driver IC and wiring assembly called the air conditioning harness assembly.
  • B1446: The No. 1 air conditioning radiator damper servo sub-assembly (driver side air mix) 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 air conditioning radiator damper servo sub-assembly (driver side air mix) to the appropriate 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 driver side is controlled. 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

B1441

Air Mix Damper Control Servo Motor Circuit (Passenger Side)

Air mix damper position sensor value does not change even if air conditioning amplifier assembly operates No. 1 air conditioning radiator damper servo sub-assembly (front passenger side air mix)

  • No. 1 air conditioning radiator damper servo sub-assembly (front passenger side air mix)
  • Air conditioning harness assembly
  • Air conditioning amplifier assembly
  • Air conditioning radiator assembly

Memorized

(30 sec. or more)*

B1443

Air Outlet Damper Control Servo Motor Circuit

Air outlet damper position sensor value does not change even if air conditioning amplifier assembly operates No. 1 air conditioning radiator damper servo sub-assembly (mode)

  • No. 1 air conditioning radiator damper servo sub-assembly (mode)
  • Air conditioning harness assembly
  • Air conditioning amplifier assembly
  • Air conditioning radiator assembly

Memorized

(30 sec. or more)*

B1446

Air Mix Damper Control Servo Motor Circuit (Driver Side)

Air mix damper position sensor value does not change even if air conditioning amplifier assembly operates No. 1 air conditioning radiator damper servo sub-assembly (driver side air mix)

  • No. 1 air conditioning radiator damper servo sub-assembly (driver side air mix)
  • Air conditioning harness assembly
  • Air conditioning amplifier assembly
  • Air conditioning radiator assembly

Memorized

(30 sec. or more)*

  • *: The air conditioning amplifier assembly stores this DTC if the malfunction has occurred for the period of time indicated in the brackets.
DTC Detection Condition Combination Table
 

Vehicle Condition

Pattern 1

Pattern 2

Diagnosis Condition

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

Malfunction

Damper servo operation request signals are output but the damper position sensor value does not change

-

Damper servo operation request signals are output but the damper position sensor value is abnormal

-

Detection Time

Continuously for 30 seconds or more

Continuously for 30 seconds or more

Trip Count

1 trip

1 trip

HINT:

If the conditions of either of these patterns are detected, a DTC will be stored.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

HINT:

  • Confirm that no mechanical problems are present because this DTC can be stored when either a damper link or damper is mechanically locked.
  • When installing a damper servo motor, make sure to install it correctly.

    Click here

  • After replacing a damper servo motor, make sure to perform Servo Motor Initialization.

    Click here

PROCEDURE

1.

CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Air Conditioner > Trouble Codes

Result

Proceed to

Only B1497 is output

A

B1441, B1442, B1443 and B1446 are output

B

B1441, B1443 or B1446 is output

C

A

GO TO DTC B1497

B

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

C

2.

INSPECT NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (INSTALLATION CONDITION)

(a) Check that the No. 1 air conditioning radiator damper servo sub-assembly is installed correctly.

OK:

The No. 1 air conditioning radiator damper servo sub-assembly is installed correctly.

NG

INSTALL NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY CORRECTLY

OK

3.

INSPECT NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (MOTOR, LINK, DAMPER)

(a) 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.

NG

REMOVE PINCHED WIRE HARNESS

OK

4.

INSPECT AIR CONDITIONING RADIATOR ASSEMBLY (DAMPER)

(a) Remove the No. 1 air conditioning radiator damper servo sub-assembly.

Click here

(b) Operate the dampers by hand.

OK:

The dampers are easily operated by hand.

OK

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

NG

REPLACE AIR CONDITIONING RADIATOR ASSEMBLY

    Open in Pressure Sensor Circuit / Abnormal Refrigerant Pressure (B1423)

    Air Inlet Damper Control Servo Motor (B1442)

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