Toyota Prius: Window Defogger System

• Precaution
• Parts Location
• System Diagram
• How To Proceed With Troubleshooting
• Operation Check
• Problem Symptoms Table
• Terminals Of Ecu
• Data List / Active Test
• Rear Window Defogger System does not Operate

Precaution

PRECAUTION

PRECAUTIONS FOR DISCONNECTING CABLE FROM NEGATIVE (-) AUXILIARY BATTERY TERMINAL

NOTICE:

After the ignition switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.

Click here

HINT:

When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.

Click here

Parts Location

PARTS LOCATION

ILLUSTRATION

*1	BACK DOOR GLASS - REAR WINDOW DEFOGGER WIRE	*2	AIR CONDITIONING AMPLIFIER ASSEMBLY
*3	AIR CONDITIONING CONTROL ASSEMBLY - REAR WINDOW DEFOGGER SWITCH	*4	MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)
*5	POWER DISTRIBUTION BOX ASSEMBLY	*6	DLC3

System Diagram

SYSTEM DIAGRAM

How To Proceed With Troubleshooting

CAUTION / NOTICE / HINT

PROCEDURE

1.	Toyota Prius Vehicle BROUGHT TO WORKSHOP

NEXT

2.	CUSTOMER PROBLEM ANALYSIS

NEXT

3.

PRE-CHECK

(a) Measure the auxiliary battery voltage with the ignition switch off.

Standard Voltage:

11 to 14 V

If the voltage is below 11 V, recharge or replace the auxiliary battery before proceeding to the next step.

(b) Check the fuses and relays.

(c) Check the connector connections and terminals to make sure that there are no abnormalities such as loose connections, deformation, etc.

(d) Check the Toyota Prius vehicle specifications.

NEXT

4.	INSPECT COMMUNICATION FUNCTION OF CAN COMMUNICATION SYSTEM*

(a) Using the GTS, check for CAN communication system DTCs.

for HEV Model: Click here

for PHEV Model: Click here

Result	Proceed to
CAN DTCs are not output	A
CAN DTCs are output	B

B

GO TO CAN COMMUNICATION SYSTEM for HEV Model: Click here for PHEV Model: Click here

A

5.	INSPECT COMMUNICATION FUNCTION OF CXPI COMMUNICATION SYSTEM*

(a) Using the GTS, check for CXPI communication system DTCs.

Result	Proceed to
CXPI DTCs are not output	A
CXPI DTCs are output	B

B

GO TO CXPI COMMUNICATION SYSTEM

A

6.	PROBLEM SYMPTOMS TABLE

(a) Refer to Problem Symptoms Table.

Click here

Result	Proceed to
Fault is not listed in Problem Symptoms Table	A
Fault is listed in Problem Symptoms Table	B

B

GO TO STEP 8

A

7.	OVERALL ANALYSIS AND TROUBLESHOOTING*

(a) Operation Check

Click here

(b) Terminals of ECU

Click here

(c) Data List / Active Test

Click here

NEXT

8.	REPAIR OR REPLACE

NEXT

9.	CONFIRMATION TEST

NEXT

END

Operation Check

OPERATION CHECK

CHECK WINDOW DEFOGGER SYSTEM

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 Toyota Prius vehicle control history (RoB) of the power steering system and check that "Battery Voltage Drop: X208F" is not stored before proceeding with troubleshooting.

Click here

(a) Turn the ignition switch to ON.

(b) Check that the rear window defogger wire becomes warm by operating the rear window defogger switch of the air conditioning control assembly.

(c) When the Toyota Prius vehicle is stopped, confirm that the window defogger system operation stops after approximately 15 minutes.

Problem Symptoms Table

PROBLEM SYMPTOMS TABLE

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 Toyota Prius vehicle control history (RoB) of the power steering system and check that "Battery Voltage Drop: X208F" is not stored before proceeding with troubleshooting.

Click here

HINT:

Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.

Window Defogger System

Symptom	Suspected Area	Link
Window defogger system does not operate	Proceed to the "Rear Window Defogger System does not Operate"

Terminals Of Ecu

TERMINALS OF ECU

CHECK POWER DISTRIBUTION BOX ASSEMBLY

(a) Measure the voltage according to the value (s) in the table below.

Tester Connection	Terminal Description	Condition	Specified Condition
R17-43 - Body ground	Rear window defogger signal (output)	Rear window defogger switch off	Below 1 V
		Rear window defogger switch on	11 to 14 V

CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY, AIR CONDITIONING CONTROL ASSEMBLY

for HEV Model: Click here

for PHEV Model: Click here

Data List / Active Test

DATA LIST / ACTIVE TEST

DATA LIST

NOTICE:

In the following table, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.

HINT:

Using the GTS to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.

(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	-
Rear Defogger Output Signal	Window defogger output condition	OFF or ON	OFF: Window defogger does not operate ON: Window defogger operates	-
Rear Defogger Output Current	Window defogger current	Min.: 0, Max.: 255 A	Current window defogger current displayed	Window defogger current when output is on
Rear Defogger Fuse Shut Off Status	Window defogger fuse condition	OFF or ON	OFF: Fuse shut off ON: Fuse not shut off	-
Rear Defogger Fuse Shut Off Count	Window defogger fuse shut off times	Min.: 0, Max.: 255 Times	0 Times	-

Body Electrical > Air Conditioner > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Rear Defogger Relay	Window defogger operation condition	OFF or ON	OFF: Window defogger does not operate ON: Window defogger operates	-

ACTIVE TEST

HINT:

Using the GTS to perform Active Tests allows relays, VSVs, actuators and other items to be operated without removing any parts. This non-intrusive functional inspection can be very useful because intermittent operation may be discovered before parts or wiring is disturbed. Performing Active Tests early in troubleshooting is one way to save diagnostic time. Data List information can be displayed while performing Active Tests.

(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	-

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

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 4

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.

NG

REPLACE POWER DISTRIBUTION BOX ASSEMBLY

OK

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

(a) Disconnect the W10 and W11 back door glass (rear window defogger wire) connectors.

(b) Disconnect the R17 power distribution box assembly connector.

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

Standard Resistance:

Click Location & Routing(W10,R17,W11) Click Connector(W10) Click Connector(R17) Click Connector(W11)

Tester Connection	Condition	Specified Condition
W10-2 (B) - R17-43	Always	Below 1 Ω
W10-2 (B) or R17-43 - Body ground	Always	10 kΩ or higher
W11-1 (E) - Body ground	Always	Below 1 Ω

OK

REPLACE BACK DOOR GLASS (REAR WINDOW DEFOGGER WIRE)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK AIR CONDITIONING SYSTEM

(a) Check the air conditioning system.

for HEV Model: Click here

for PHEV Model: 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 HEV Model: Click here for PHEV Model: Click here

OK

5.	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

6.	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 (Back door glass)	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