| Last Modified: 07-31-2024 | 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](/t3Portal/stylegraphics/info.gif)
for Gasoline Model: Click here
-
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
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 |
|
|
|
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 |
|
| C |
|
|
|
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 |
|
| 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 |
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
5. |
CHECK AIR CONDITIONING SYSTEM |
(a) Check the air conditioning system.
for HV Model: Click here
for Gasoline Model, with Automatic Air Conditioning System: Click here
for Gasoline Model, with Manual Air Conditioning System for Electrical Control Type: Click here
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
for Gasoline Model, with Automatic Air Conditioning System: Click here
for Gasoline Model, with Manual Air Conditioning System for Electrical Control Type: Click here
|
|
|
6. |
CHECK AIR CONDITIONING CONTROL ASSEMBLY |
(a) Check that the indicator illuminates when the window defogger switch is on.
OK:
Defogger indicator illuminates.
| NG |
|
|
|
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 |
|
| NG |
|
|
|