Toyota Yaris: Air Conditioning System / Air Inlet Damper Control Servo Motor Actuator Stuck Off (B143B7F)

Toyota Yaris XP210 (2020-2024) Reapir and Service Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System / Air Inlet Damper Control Servo Motor Actuator Stuck Off (B143B7F)

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, which controls the air inlet switching.

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
B143B7F	Air Inlet Damper Control Servo Motor Actuator Stuck Off	Diagnosis Condition: No. 1 blower damper servo sub-assembly operating Malfunction Status: Damper servo operation request signals are output but the damper position sensor value does not change or abnormal Detection Time: Continuously for 30 seconds or more	No. 1 blower damper servo sub-assembly Air conditioning harness assembly Air conditioning radiator assembly	Memorized

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

B143B7F

Air Inlet Damper Control Servo Motor Actuator Stuck Off

Diagnosis Condition:

No. 1 blower damper servo sub-assembly operating

Malfunction Status:

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

Detection Time:

Continuously for 30 seconds or more

No. 1 blower damper servo sub-assembly
Air conditioning harness assembly
Air conditioning radiator assembly

Memorized

DTC Detection Condition Combination Table

		Vehicle Condition
		Pattern 1	Pattern 2
Diagnosis Condition	No. 1 blower damper servo sub-assembly operating	○	○
Malfunction	Damper servo operation request signals are output but the damper position sensor value does not change	○	-
Malfunction	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

NOTICE:

This DTC is also output for the damper link, damper lock, etc. Before performing inspection, perform servomotor initialization and check that there are no mechanical malfunctions.
Click here
This DTC is also output when servomotor initialization has failed. When servomotor initialization has failed, repair any malfunctions and perform servomotor initialization again.
Click here

PROCEDURE

1.	CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Air Conditioner > Trouble Codes

Result	Proceed to
B14037F, B14067F and B143B7F are output	A
Only B143B7F is output	B

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

2.	PERFORM ACTIVE TEST USING GTS (AIR INLET DAMPER CONTROL SERVO MOTOR)

(a) 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 Control Servo Motor	No. 1 blower damper servo sub-assembly pulse	Min.: 128 Max.: 384	-

Tester Display

Measurement Item

Control Range

Diagnostic Note

Air Inlet Damper Control Servo Motor

No. 1 blower damper servo sub-assembly pulse

Min.: 128

Max.: 384

Body Electrical > Air Conditioner > Active Test

Tester Display
Air Inlet Damper Control Servo Motor

Result	Proceed to
No. 1 air conditioning radiator damper servo sub-assembly operates	A
No. 1 air conditioning radiator damper servo sub-assembly does not operate at all	B

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

3.	CHECK NO. 1 BLOWER DAMPER SERVO SUB-ASSEMBLY

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

Click here

OK:

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

INSTALL NO. 1 BLOWER DAMPER SERVO SUB-ASSEMBLY

4.	CHECK 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.

REMOVE PINCHED WIRE HARNESS

5.	CHECK BLOWER ASSEMBLY

(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.

REPLACE BLOWER ASSEMBLY

6.	INSPECT AIR CONDITIONING HARNESS ASSEMBLY

(a) Disconnect the h7 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
h7-1 (M-) - h4-5 (M-)	Always	Below 1 Ω
h7-2 (M+) - h4-4 (M+)	Always	Below 1 Ω
h7-3 (STE2) - h4-3 (sigB)	Always	Below 1 Ω
h7-4 (STE1) - h4-2 (sigA)	Always	Below 1 Ω
h7-5 (GND) - h4-1 (GND)	Always	Below 1 Ω
h7-1 (M-) or h4-5 (M-) - Other terminals and body ground	Always	10 kΩ or higher
h7-2 (M+) or h4-4 (M+) - Other terminals and body ground	Always	10 kΩ or higher
h7-3 (STE2) or h4-3 (sigB) - Other terminals and body ground	Always	10 kΩ or higher
h7-4 (STE1) or h4-2 (sigA) - Other terminals and body ground	Always	10 kΩ or higher

REPLACE NO. 1 BLOWER DAMPER SERVO SUB-ASSEMBLY

REPAIR OR REPLACE AIR CONDITIONING HARNESS ASSEMBLY

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