Last Modified: 07-31-2024 6.11:8.1.0 Doc ID: RM1000000028C3T
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): B144C7F; Front Left Air Mix Damper Control Servo Motor Actuator Stuck Off; 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [11/2022 -        ]

DTC

B144C7F

Front Left Air Mix Damper Control Servo Motor Actuator Stuck Off

DESCRIPTION

The No. 1 air conditioning radiator 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 outlet damper to the appropriate position, which controls the air outlet switching.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

B144C7F

Front Left Air Mix Damper Control Servo Motor Actuator Stuck Off

Diagnosis Condition:

  • No. 1 air conditioning radiator damper servo sub-assembly operating

Malfunction:

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

Detection Time:

  • Continuously for 30 seconds or more
  • No. 1 air conditioning radiator 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 air conditioning radiator damper servo sub-assembly operating

○

○

Malfunction

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

○

-

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

for M20A-FKS:
for G16E-GTS:

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 Hatchback GR Corolla [11/2022 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Gasoline Model with Automatic Air Conditioning System): 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 Hatchback GR Corolla [11/2022 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Gasoline Model with Automatic Air Conditioning System): INITIALIZATION

PROCEDURE

1.

CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Air Conditioner > Trouble Codes

Result

Proceed to

B144C7F is output

A

DTCs in conjunction with No. 1 air conditioning radiator damper servo sub-assembly are output at same time

B
B

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

A

2.

CHECK NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (INSTALLATION CONDITION)

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

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

OK:

No. 1 air conditioning radiator damper servo sub-assembly is installed correctly.

NG

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

OK

3.

CHECK NO. 1 AIR CONDITIONING RADIATOR 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.

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

Front Left Air Mix Damper Control Servo Motor

This test activates the front left air mix damper control servo motor.

(No. 1 air conditioning radiator damper servo sub-assembly (left side air mix))

128: Min

384: Max

Operate with the ignition switch ON.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Inspection Item

Front Left Air Mix Damper Control Servo Motor Actual Pulse

No. 1 air conditioning radiator damper servo sub-assembly (left side air mix) actual pulse

128 to 384
  • MAX COLD: 257 (pulse)
  • MAX HOT: 165 (pulse)

No. 1 air conditioning radiator damper servo sub-assembly (left side air mix) circuit malfunction

Body Electrical > Air Conditioner > Active Test

Active Test Display

Front Left Air Mix Damper Control Servo Motor

Data List Display

Front Left Air Mix Damper Control Servo Motor Actual Pulse

OK:

The value of the Data List changes in accordance with the operation of the Active Test.

NG

GO TO STEP 8

OK

5.

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

Front Left Air Mix Damper Control Servo Motor

This test activates the front left air mix damper control servo motor.

(No. 1 air conditioning radiator damper servo sub-assembly (left side air mix))

128: Min

384: Max

Operate with the ignition switch ON.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Inspection Item

Front Left Air Mix Damper Control Servo Motor Target Pulse

No. 1 air conditioning radiator damper servo sub-assembly (left side air mix) target pulse

128 to 384
  • MAX COLD: 257 (pulse)
  • MAX HOT: 165 (pulse)

No. 1 air conditioning radiator damper servo sub-assembly (left side air mix) circuit malfunction

Front Left Air Mix Damper Control Servo Motor Actual Pulse

No. 1 air conditioning radiator damper servo sub-assembly (left side air mix) actual pulse

128 to 384
  • MAX COLD: 257 (pulse)
  • MAX HOT: 165 (pulse)

No. 1 air conditioning radiator damper servo sub-assembly (left side air mix) circuit malfunction

Body Electrical > Air Conditioner > Active Test

Active Test Display

Front Left Air Mix Damper Control Servo Motor

Data List Display

Front Left Air Mix Damper Control Servo Motor Target Pulse

Front Left Air Mix Damper Control Servo Motor Actual Pulse

OK:

The target pulse value of the Data List matches the actual pulse.

OK

USE SIMULATION METHOD TO CHECK

NG

6.

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

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

NEXT

7.

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

Front Left Air Mix Damper Control Servo Motor

This test activates the front left air mix damper control servo motor.

(No. 1 air conditioning radiator damper servo sub-assembly (left side air mix))

128: Min

384: Max

Operate with the ignition switch ON.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Inspection Item

Front Left Air Mix Damper Control Servo Motor Actual Pulse

No. 1 air conditioning radiator damper servo sub-assembly (left side air mix) actual pulse

128 to 384
  • MAX COLD: 257 (pulse)
  • MAX HOT: 165 (pulse)

No. 1 air conditioning radiator damper servo sub-assembly (left side air mix) circuit malfunction

Body Electrical > Air Conditioner > Active Test

Active Test Display

Front Left Air Mix Damper Control Servo Motor

Data List Display

Front Left Air Mix Damper Control Servo Motor Actual Pulse

OK:

The value of the Data List changes in accordance with the operation of the Active Test.

OK

END
NG

REPLACE AIR CONDITIONING HARNESS ASSEMBLY

8.

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

Front Air Outlet Damper Control Servo Motor

This test activates the front air outlet damper control servo motor.

(No. 1 air conditioning radiator damper servo sub-assembly (front mode))

128: Min

384: Max

Operate with the ignition switch ON.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Inspection Item

Front Air Outlet Damper Control Servo Motor Actual Pulse

No. 1 air conditioning radiator damper servo sub-assembly (front mode) actual pulse

128 to 384
  • FACE: 256 (pulse)
  • B/L: 267 (pulse)
  • FOOT-A: 288 (pulse)
  • FOOT-R (F): 297 (pulse)
  • FOOT-D: 305 (pulse)
  • F/D-R: 320 (pulse)
  • D/F: 339 (pulse)
  • DEF: 348 (pulse)

No. 1 air conditioning radiator damper servo sub-assembly (front mode) circuit malfunction

Body Electrical > Air Conditioner > Active Test

Active Test Display

Front Air Outlet Damper Control Servo Motor

Data List Display

Front Air Outlet Damper Control Servo Motor Actual Pulse

OK:

The value of the Data List changes in accordance with the operation of the Active Test.

OK

GO TO STEP 6

NG

9.

CHECK AIR CONDITIONING RADIATOR ASSEMBLY (DAMPER)

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

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

(b) Operate the dampers by hand.

OK:

The dampers are easily operated by hand.

OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

NG

REPAIR OR REPLACE AIR CONDITIONING RADIATOR ASSEMBLY