DTC B143A-87: Lost Communication with Air Inlet Damper Control Servo Motor LIN Missing Message [11/2021 - ]: Procedure

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CHECK FOR DTC

Check for DTCs.

Body Electrical > Air Conditioner > Trouble Codes

Result

Result	Proceed to
DTC B142A-88 is output	A
DTC B142A-88 is not output	B

Result:

GO TO DTC B142A-88. Refer to DTC B142A-88: Servo Motor LIN Communication Bus off [11/2021 - ]

Result:

See step 2

INSPECT AIR CONDITIONING HARNESS ASSEMBLY

Disconnect the A No. 1 air conditioning radiator damper servo sub-assembly connector.
Disconnect the B No. 3 air conditioning radiator damper servo sub-assembly connector.

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

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Front view of wire harness connector
(to No. 1 Air Conditioning Radiator Damper Servo Sub-assembly)

Front view of wire harness connector
(to No. 3 Air Conditioning Radiator Damper Servo Sub-assembly)

Standard Resistance

Tester Connection	Condition	Specified Condition
A-1 (M-) - B-5 (M-)	Always	Below 1 Ω
A-2 (M+) - B-4 (M+)	Always	Below 1 Ω
A-3 (STE2) - B-3 (STE2)	Always	Below 1 Ω
A-4 (STE1) - B-2 (STE1)	Always	Below 1 Ω
A-5 (GND) - B-1 (GND)	Always	Below 1 Ω
A-1 (M-) or B-5 (M-) - Other terminals and body ground	Always	10 kΩ or higher
A-2 (M+) or B-4 (M+) - Other terminals and body ground	Always	10 kΩ or higher
A-3 (STE2) or B-3 (STE2) - Other terminals and body ground	Always	10 kΩ or higher
A-4 (STE1) or B-2 (STE1) - Other terminals and body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

Result:

REPLACE NO. 3 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY. Refer to DISASSEMBLY [11/2021 - ]

Result:

REPLACE AIR CONDITIONING HARNESS ASSEMBLY. Refer to DISASSEMBLY [11/2021 - ]