Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM1000000026Z3Y
Model Year Start: 2023 Model: Corolla Prod Date Range: [09/2022 -           ]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): B143B7F; Air Inlet Damper Control Servo Motor Actuator Stuck Off; 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]

DTC

B143B7F

Air Inlet Damper Control Servo Motor Actuator Stuck Off

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 No. 1 blower damper servo sub-assembly to the appropriate position to change the air inlet mode (fresh, recirculation/fresh, and recirculation).

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:

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

Memorized

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

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 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): INITIALIZATION

  • 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 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): INITIALIZATION

PROCEDURE

1.

CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Air Conditioner > Trouble Codes

Result

Proceed to

DTC B14037F, B14067F and B143B7F are output

A

DTC B143B7F is output

B
A

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

B

2.

PERFORM ACTIVE TEST USING GTS

(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

This test activates the Air Inlet Damper Control Servo Motor.

(No. 1 blower damper servo sub-assembly)

128: Min

384: Max

Operate with ignition switch ON.

Body Electrical > Air Conditioner > Active Test

Tester Display

Air Inlet Damper Control Servo Motor

OK:

No. 1 blower damper servo sub-assembly is operated.

NG

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

OK

3.

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

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

Click here 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 -        ]; HEATING / AIR CONDITIONING: BLOWER UNIT: REASSEMBLY

OK:

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

NG

REINSTALL NO. 1 BLOWER DAMPER SERVO SUB-ASSEMBLY

OK

4.

CHECK BLOWER DAMPER SERVO SUB-ASSEMBLY NO.1 (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

5.

CHECK BLOWER ASSEMBLY (DAMPER)

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

Click here 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 -        ]; HEATING / AIR CONDITIONING: BLOWER UNIT: DISASSEMBLY

(b) Operate the dampers by hand.

OK:

The dampers are easily operated by hand.

NG

REPAIR OR REPLACE BLOWER ASSEMBLY 2023 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 - 11/2022]; HEATING / AIR CONDITIONING: BLOWER UNIT: REMOVAL 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [11/2022 -        ]; HEATING / AIR CONDITIONING: BLOWER UNIT: REMOVAL

OK

6.

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

REPAIR AIR CONDITIONING HARNESS ASSEMBLY