Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM1000000028LUN
Model Year Start: 2023 Model: GR Corolla Prod Date Range: [11/2022 -           ]
Title: WINDOW / GLASS: WINDOW DEFOGGER SYSTEM: Rear Window Defogger System does not Operate; 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [11/2022 -        ]

Rear Window Defogger System does not Operate

DESCRIPTION

When the rear defogger switch on the air conditioning control assembly is operated, an operation request signal is sent to the air conditioning amplifier assembly via CAN communication. When the air conditioning amplifier assembly receives an operation request signal, an operation request signal is sent to the main body ECU (multiplex network body ECU) via CAN communication. The main body ECU (multiplex network body ECU) turns on the RR DEF relay through the IC of the power distribution box assembly and the window defogger operates.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • If the window defogger system is operated when the auxiliary battery voltage is low, due to the electrical load limit control that gives voltage supply priority to the power steering system, the window defogger system may not operate. In this case, check the vehicle control history (RoB) of the power steering system and check that "Battery Voltage Drop: X208F" is not stored before proceeding with troubleshooting.

    for HV Model: Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; POWER ASSIST SYSTEMS: POWER STEERING SYSTEM (for HV Model): VEHICLE CONTROL HISTORY

    for Gasoline Model: Click here 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [11/2022 -        ]; POWER ASSIST SYSTEMS: POWER STEERING SYSTEM (for Gasoline Model): VEHICLE CONTROL HISTORY

  • The window defogger system uses the CAN communication system and CXPI communication system. First, confirm that there are no malfunctions in the CAN communication system and CXPI communication system. Refer to How to Proceed with Troubleshooting.

    Click here 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [11/2022 -        ]; WINDOW / GLASS: WINDOW DEFOGGER SYSTEM: HOW TO PROCEED WITH TROUBLESHOOTING

PROCEDURE

1.

READ VALUE USING GTS (REAR DEFOGGER INPUT SIGNAL)

(a) Read the Data List according to the display on the GTS.

Body Electrical > Power Distribution Box > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Rear Defogger Input Signal

Window defogger switch signal input condition

OFF or ON

OFF: Window defogger switch is off

ON: Window defogger switch is on

-

Body Electrical > Power Distribution Box > Data List

Tester Display

Rear Defogger Input Signal

OK:

On the GTS screen, ON or OFF is displayed accordingly.

NG

GO TO STEP 5

OK

2.

READ VALUE USING GTS (REAR DEFOGGER OUTPUT SIGNAL)

(a) Read the Data List according to the display on the GTS.

Body Electrical > Power Distribution Box > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Rear Defogger Output Signal

Window defogger output condition

OFF or ON

OFF: Window defogger does not operate

ON: Window defogger operates

-

Body Electrical > Power Distribution Box > Data List

Tester Display

Rear Defogger Output Signal

OK:

On the GTS screen, ON or OFF is displayed accordingly.

Result

Proceed to

OK (except Sedan)

A

OK (for Sedan)

B

NG

C

B

GO TO STEP 4

C

REPLACE POWER DISTRIBUTION BOX ASSEMBLY

A

3.

CHECK HARNESS AND CONNECTOR (REAR WINDOW DEFOGGER WIRE (BACK DOOR GLASS) - POWER DISTRIBUTION BOX ASSEMBLY AND BODY GROUND)

(a) Disconnect the V20 and V21 rear window defogger wire (back door glass) connectors.

(b) Disconnect the 8H power distribution box assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

V20-1 (B) - 8H-43

Always

Below 1 Ω

V20-1 (B) or 8H-43 - Body ground

Always

10 kΩ or higher

V21-1 (E) - Body ground

Always

Below 1 Ω

OK

REPLACE REAR WINDOW DEFOGGER WIRE (BACK DOOR GLASS)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.

CHECK HARNESS AND CONNECTOR (REAR WINDOW DEFOGGER WIRE (BACK WINDOW GLASS) - POWER DISTRIBUTION BOX ASSEMBLY AND BODY GROUND)

(a) Disconnect the O114 and w1 rear window defogger wire (back window glass) connectors.

(b) Disconnect the 8H power distribution box assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

O114-1 (B) - 8H-43

Always

Below 1 Ω

O114-1 (B) or 8H-43 - Body ground

Always

10 kΩ or higher

w1-1 (E) - Body ground

Always

Below 1 Ω

OK

REPLACE REAR WINDOW DEFOGGER WIRE (BACK WINDOW GLASS)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.

CHECK AIR CONDITIONING SYSTEM

(a) Check the air conditioning system.

for HV Model: Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): HOW TO PROCEED WITH TROUBLESHOOTING

for Gasoline Model, with Automatic Air Conditioning System: 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): HOW TO PROCEED WITH TROUBLESHOOTING

for Gasoline Model, with Manual Air Conditioning System for Electrical Control Type: Click here 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [11/2022 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Gasoline Model with Manual Air Conditioning System): HOW TO PROCEED WITH TROUBLESHOOTING

HINT:

Both the window defogger system operation signal and air conditioning system operation signal are transmitted to the air conditioning amplifier assembly via the same communication line.

OK:

The air conditioning system operates normally.

NG

GO TO AIR CONDITIONING SYSTEM

for HV Model: Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): HOW TO PROCEED WITH TROUBLESHOOTING

for Gasoline Model, with Automatic Air Conditioning System: 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): HOW TO PROCEED WITH TROUBLESHOOTING

for Gasoline Model, with Manual Air Conditioning System for Electrical Control Type: Click here 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [11/2022 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Gasoline Model with Manual Air Conditioning System): HOW TO PROCEED WITH TROUBLESHOOTING

OK

6.

CHECK AIR CONDITIONING CONTROL ASSEMBLY

(a) Check that the indicator illuminates when the window defogger switch is on.

OK:

Defogger indicator illuminates.

NG

REPLACE AIR CONDITIONING CONTROL ASSEMBLY

OK

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

Rear Defogger Relay

Rear window defogger wire

OFF or ON

-

Body Electrical > Air Conditioner > Active Test

Tester Display

Rear Defogger Relay

OK:

The window defogger system operates normally.

OK

REPLACE AIR CONDITIONING CONTROL ASSEMBLY

NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY