Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM1000000028C3Q
Model Year Start: 2023 Model: GR Corolla Prod Date Range: [11/2022 -           ]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Gasoline Model with Automatic Air Conditioning System): B143A87; Lost Communication with Air Inlet Damper Control Servo Motor LIN Missing Message; 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [11/2022 -        ]

DTC

B143A87

Lost Communication with Air Inlet Damper Control Servo Motor LIN Missing Message

DESCRIPTION

for M20A-FKS:

  • The air conditioning harness assembly connects the air conditioning amplifier assembly and No. 1 blower damper servo sub-assembly.

    The No. 1 blower damper servo sub-assembly sends damper position information to the air conditioning amplifier assembly.

for G16E-GTS:

  • The air conditioning harness assembly connects the air conditioning amplifier assembly and No. 5 air conditioning radiator damper servo sub-assembly.

    The No. 5 air conditioning radiator damper servo sub-assembly sends damper position information to the air conditioning amplifier assembly.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

B143A87

Lost Communication with Air Inlet Damper Control Servo Motor LIN Missing Message

Diagnosis Condition:

  • Ignition switch ON

Malfunction:

  • Error or open in communication line between air conditioning amplifier assembly and No. 1 blower damper servo sub-assembly*1
  • Error or open in communication line between air conditioning amplifier assembly and No. 5 air conditioning radiator damper servo sub-assembly*2

Detection Time:

  • Continuously for 10 seconds or more
  • Air conditioning harness assembly
  • No. 1 blower damper servo sub-assembly*1
  • No. 5 air conditioning radiator damper servo sub-assembly*2

Memorized

DTC Detection Condition Combination Table

 

Vehicle Condition

Pattern 1

Pattern 2

Diagnosis Condition

Ignition switch ON

Malfunction

  • Error in communication line between air conditioning amplifier assembly and No. 1 blower damper servo sub-assembly*1
  • Error in communication line between air conditioning amplifier assembly and No. 5 air conditioning radiator damper servo sub-assembly*2

-

  • Open in communication line between air conditioning amplifier assembly and No. 1 blower damper servo sub-assembly*1
  • Open in communication line between air conditioning amplifier assembly and No. 5 air conditioning radiator damper servo sub-assembly*2

-

Detection Time

Continuously for 10 seconds or more

Continuously for 10 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.

  • *1: for M20A-FKS
  • *2: for G16E-GTS

WIRING DIAGRAM

for M20A-FKS:
for G16E-GTS:

PROCEDURE

1.

CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Air Conditioner > Trouble Codes

Result

Proceed to

DTC B142A88 is output

A

DTC B142A88 is not output

B

A

GO TO DTC B142A88

B

2.

CONFIRM MODEL

Result

Proceed to

for M20A-FKS

A

for G16E-GTS

B

B

GO TO STEP 4

A

3.

INSPECT AIR CONDITIONING HARNESS ASSEMBLY

(a) Disconnect the m4 No. 1 air conditioning radiator damper servo sub-assembly connector.

(b) Disconnect the m1 No. 1 blower damper servo sub-assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

m4-1 (M-) - m1-5 (M-)

Always

Below 1 Ω

m4-2 (M+) - m1-4 (M+)

Always

Below 1 Ω

m4-3 (STE2) - m1-3 (STE2)

Always

Below 1 Ω

m4-4 (STE1) - m1-2 (STE1)

Always

Below 1 Ω

m4-5 (GND) - m1-1 (GND)

Always

Below 1 Ω

m4-1 (M-) or m1-5 (M-) - Other terminals and body ground

Always

10 kΩ or higher

m4-2 (M+) or m1-4 (M+) - Other terminals and body ground

Always

10 kΩ or higher

m4-3 (STE2) or m1-3 (STE2) - Other terminals and body ground

Always

10 kΩ or higher

m4-4 (STE1) or m1-2 (STE1) - Other terminals and body ground

Always

10 kΩ or higher

OK

REPLACE NO. 1 BLOWER DAMPER SERVO SUB-ASSEMBLY

NG

REPLACE AIR CONDITIONING HARNESS ASSEMBLY

4.

INSPECT AIR CONDITIONING HARNESS ASSEMBLY

(a) Disconnect the m4 No. 1 air conditioning radiator damper servo sub-assembly connector.

(b) Disconnect the m1 No. 5 air conditioning radiator damper servo sub-assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

m4-1 (M-) - m1-5 (M-)

Always

Below 1 Ω

m4-2 (M+) - m1-4 (M+)

Always

Below 1 Ω

m4-3 (STE2) - m1-3 (STE2)

Always

Below 1 Ω

m4-4 (STE1) - m1-2 (STE1)

Always

Below 1 Ω

m4-5 (GND) - m1-1 (GND)

Always

Below 1 Ω

m4-1 (M-) or m1-5 (M-) - Other terminals and body ground

Always

10 kΩ or higher

m4-2 (M+) or m1-4 (M+) - Other terminals and body ground

Always

10 kΩ or higher

m4-3 (STE2) or m1-3 (STE2) - Other terminals and body ground

Always

10 kΩ or higher

m4-4 (STE1) or m1-2 (STE1) - Other terminals and body ground

Always

10 kΩ or higher

OK

REPLACE NO. 5 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY

NG

REPLACE AIR CONDITIONING HARNESS ASSEMBLY