Toyota Avalon Service & Repair Manual: Air Inlet Damper Control Servo Motor (B1442)

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

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 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 blower damper servo sub-assembly operating

Malfunction

Air inlet damper servo operation request signals are output but the air inlet damper position sensor value does not change

-

Air inlet damper servo operation request signals are output but the air inlet 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

Only B1442 is output

C

A

GO TO DTC B1497

B

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

C

2.

INSPECT NO. 1 BLOWER DAMPER SERVO SUB-ASSEMBLY (INSTALLATION CONDITION)

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

OK:

The No. 1 blower damper servo sub-assembly is installed correctly.

NG

INSTALL NO. 1 BLOWER DAMPER SERVO SUB-ASSEMBLY

OK

3.

INSPECT NO. 1 BLOWER 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 NO. 1 BLOWER DAMPER SERVO SUB-ASSEMBLY (DAMPER)

(a) Remove the No. 1 blower damper servo sub-assembly.

Click here

(b) Operate the air inlet dampers by hand.

OK:

The air inlet dampers are easily operated by hand.

NG

REPLACE BLOWER ASSEMBLY

OK

5.

INSPECT AIR CONDITIONING HARNESS ASSEMBLY

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A-6 (STE2) - B-3 (sigB)

Always

Below 1 Ω

A-5 (STE1) - B-2 (sigA)

Always

Below 1 Ω

A-8 (M-) - B-5 (M-)

Always

Below 1 Ω

A-7 (M+) - B-4 (M+)

Always

Below 1 Ω

A-4 (GND) - B-1 (GND)

Always

Below 1 Ω

A-6 (STE2) or B-3 (sigB) - Other terminals and Body ground

Always

10 kΩ or higher

A-5 (STE1) or B-2 (sigA) - Other terminals and Body ground

Always

10 kΩ or higher

A-8 (M-) or B-5 (M-) - Other terminals and Body ground

Always

10 kΩ or higher

A-7 (M+) or B-4 (M+) - Other terminals and Body ground

Always

10 kΩ or higher

NG

REPLACE AIR CONDITIONING HARNESS ASSEMBLY

OK

6.

PERFORM ACTIVE TEST USING TECHSTREAM

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

(b) Remove the No. 2 air conditioning radiator damper servo sub-assembly.

Click here

(c) Connect the No. 1 blower damper servo sub-assembly connector to the No. 2 air conditioning radiator damper servo sub-assembly.

(d) Connect the Techstream to the DLC3.

(e) Turn the engine switch on (IG).

(f) Turn the Techstream on.

(g) Enter the following menus: Body Electrical / Air Conditioner / Active Test.

(h) Perform the Active Test according to the display on the Techstream.

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 and 256 pulses

  • *: Though this Active Test is for the No. 1 blower damper servo sub-assembly, in this case it is used to check the operation of the No. 2 air conditioning radiator damper servo sub-assembly.
Body Electrical > Air Conditioner > Active Test

Tester Display

Air Inlet Damper Targ Pulse

OK:

The No. 2 air conditioning radiator damper servo sub-assembly operates.

OK

REPLACE NO. 1 BLOWER DAMPER SERVO SUB-ASSEMBLY

NG

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

    Air Mix Damper Control Servo Motor Circuit (Passenger Side) (B1441,B1443,B1446)

    Air Outlet Damper Control Servo Motor Circuit (Rear) (B1449)

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