Lexus ES: Wiper Switch Signal Mismatch between LIN and Line (B1372)

DESCRIPTION

Under normal operation, the windshield wiper motor assembly receives operation signals from the windshield wiper switch assembly via LIN communication.

The windshield wiper motor assembly and windshield wiper switch assembly are also connected via direct line in order to operate the front wipers in HI in an emergency. If the operation signals sent via LIN communication and direct line do not match, this DTC is stored.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Memory	DTC Output from
B1372	Wiper Switch Signal Mismatch between LIN and Line	Auxiliary battery voltage is 9.5 V or more The operation signals sent via LIN communication and direct line do not match 10 seconds or more	Windshield wiper motor assembly Main body ECU (multiplex network body ECU) Steering sensor Harness or connector	○	Wiper

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Before replacing the main body ECU (multiplex network body ECU), refer to Registration.

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PROCEDURE

1.

CLEAR DTC

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Wiper / Trouble Codes.

(e) Clear the DTCs.

Body Electrical > Wiper > Clear DTCs

NEXT

2.	CHECK FOR DTC

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Wait 10 seconds or more.

(d) Turn the Techstream on.

(e) Enter the following menus: Body Electrical / Wiper / Trouble Codes.

(f) Check for DTCs.

Body Electrical > Wiper > Trouble Codes

Result	Proceed to
DTC B1372 is not output	A
DTC B1372 is output	B

A

USE SIMULATION METHOD TO CHECK

B

3.	READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Wiper / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Wiper > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Wiper Switch HI (Line)	Front wiper switch HI position signal (direct line)	OFF or ON	OFF: Front wiper switch not in HI position ON: Front wiper switch in HI position	-

Body Electrical > Wiper > Data List

Tester Display
Wiper Switch HI (Line)

OK:

The Techstream display is normal.

NG

GO TO STEP 7

OK

4.	READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Chassis / Steering Angle Sensor / Data List.

(e) Read the Data List according to the display on the Techstream.

Chassis > Steering Angle Sensor > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Wiper Hi Switch	Front wiper switch HI position signal	OFF or ON	OFF: Front wiper switch not in HI position ON: Front wiper switch in HI position	-

Chassis > Steering Angle Sensor > Data List

Tester Display
Wiper Hi Switch

OK:

The Techstream display is normal.

NG

REPLACE STEERING SENSOR

OK

5.	CHECK HARNESS AND CONNECTOR (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) - WINDSHIELD WIPER MOTOR ASSEMBLY)

(a) Disconnect the G36 main body ECU (multiplex network body ECU) connector.

(b) Disconnect the A38 windshield wiper motor assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
G36-3 (LIN3) - A38-2 (LIN)	Always	Below 1 Ω
G36-3 (LIN3) or A38-2 (LIN) - Body ground	Always	10 kΩ Higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

6.	CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

*a	Component without harness connected (Main Body ECU (Multiplex Network Body ECU)

(a) Check for voltage and pulses according to the value(s) in the table below.

Standard Voltage:

Tester Connection	Condition	Specified Condition
G36-3 (LIN3) - Body ground	Power switch off	Below 1 V
	Power switch on (IG)	Pulse generation

OK

REPLACE WINDSHIELD WIPER MOTOR ASSEMBLY

NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

7.	CHECK HARNESS AND CONNECTOR (STEERING SENSOR - WINDSHIELD WIPER MOTOR ASSEMBLY)

(a) Disconnect the G62 steering sensor connector.

(b) Disconnect the A38 windshield wiper motor assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
G62-2 (2S) - A38-3 (2S)	Always	Below 1 Ω
G62-2 (2S) or A38-3 (2S) - Body ground	Always	10 kΩ Higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

8.	INSPECT STEERING SENSOR

*a

Component without harness connected (Steering Sensor)

-

-

(a) Remove the steering sensor.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
G62-2 (2S) - z10-27 (+2)	Always	Below 1 Ω

OK

REPLACE WINDSHIELD WIPER MOTOR ASSEMBLY

NG

REPLACE STEERING SENSOR

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