Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual: Wiper Switch Signal Mismatch between LIN and Line (B1372)

Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual / Vehicle Exterior / Wiper / Washer / Wiper And Washer System / Wiper Switch Signal Mismatch between LIN and Line (B1372)

DESCRIPTION

Under normal operation, the front wiper motor and link assembly (wiper ECU) receives operation signals from the windshield wiper switch assembly via LIN communication.

The windshield front wiper motor and link assembly (wiper ECU) 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

When the battery voltage is 9.5 V or more, the operation signals sent via LIN communication and direct line do not match for 10 seconds or more.
  • Front wiper motor and link assembly (wiper ECU)
  • Windshield wiper switch assembly
  • Harness or connector

○

Front wiper motor and link assembly (wiper ECU)

WIRING DIAGRAM

PROCEDURE

1.

READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine 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 LO

Front wiper control switch LO position signal

ON or OFF

ON: Front wiper control switch in LO position

OFF: Front wiper control switch not in LO position

-

Wiper Switch HI

Front wiper control switch HI position signal

ON or OFF

ON: Front wiper control switch in HI position

OFF: Front wiper control switch not in HI position

-

Wiper Switch AUTO

Front wiper control switch AUTO position signal*1

ON or OFF

ON: Front wiper control switch in AUTO position

OFF: Front wiper control switch not in AUTO position

The AUTO position of the front wiper control switch can be changed between AUTO and INT operation using a customize setting

Wiper Switch MIST

Front wiper control switch MIST position signal

ON or OFF

ON: Front wiper control switch in MIST position

OFF: Front wiper control switch not in MIST position

-

Wiper Switch INT

Front wiper control switch INT position signal*2

ON or OFF

ON: Front wiper control switch in INT position

OFF: Front wiper control switch not in INT position

-

Wiper Switch HI (Line)

Front wiper control switch HI position signal

ON or OFF

ON: Front wiper control switch in HI position

OFF: Front wiper control switch not in HI position

-
  • *1: w/ Auto Wiper System
  • *2: w/o Auto Wiper System
Body Electrical > Wiper > Data List

Tester Display

Wiper Switch LO

Wiper Switch HI

Wiper Switch AUTO

Wiper Switch MIST

Wiper Switch INT

Wiper Switch HI (Line)

Result

Proceed to

Data List item "Wiper Switch HI (Line)" only is always ON.

A

Data List item "Wiper Switch HI (Line)" only is always OFF.

Data List item "Wiper Switch HI (Line)" changes correctly according to the wiper switch operation, but other Data List items do not change correctly.

B

All of the Data List items change according to the wiper switch operation.

C
B

GO TO STEP 4

C

USE SIMULATION METHOD TO CHECK

A

2.

CHECK HARNESS AND CONNECTOR (FRONT WIPER MOTOR AND LINK ASSEMBLY - WINDSHIELD WIPER SWITCH ASSEMBLY)

(a) Disconnect the J31 windshield wiper switch assembly connector.

(b) Disconnect the i1 front wiper motor and link assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J31-9 (2S) - i1-1 (2S)

Always

Below 1 Ω

J31-9 (2S) or i1-1 (2S) - Body ground

Always

10 kΩ Higher
OK

GO TO STEP 5

NG

3.

CHECK WIPER MOTOR WIRE

(a) Remove the wiper motor wire.

Click here

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

i1-1 (2S) - iA1-4

Always

Below 1 Ω

*a

Front view of wire harness connector

(to Front Wiper Motor and Link Assembly)

*b

Front view of wire harness connector

(to Wire Harness)
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR
NG

REPLACE WIPER MOTOR WIRE

4.

CHECK HARNESS AND CONNECTOR (FRONT WIPER MOTOR AND LINK ASSEMBLY - WINDSHIELD WIPER SWITCH ASSEMBLY)

(a) Disconnect the J31 windshield wiper switch assembly connector.

(b) Disconnect the i1 front wiper motor and link assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J31-7 (MPX1) - i1-2 (MPX1)

Always

Below 1 Ω

J31-7 (MPX1) or i1-2 (MPX1) - Body ground

Always

10 kΩ Higher
NG

GO TO STEP 6

OK

5.

REPLACE WINDSHIELD WIPER SWITCH ASSEMBLY

(a) Replace the windshield wiper switch assembly with a new or known good one.

Click here

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

(c) Check for DTCs.

Click here

Body Electrical > Wiper > Trouble Codes

Result

Proceed to

DTC B1372 is not output.

A

DTC B1372 is output.

B
A

END
B

REPLACE FRONT WIPER MOTOR AND LINK ASSEMBLY

6.

CHECK WIPER MOTOR WIRE

(a) Remove the wiper motor wire.

Click here

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

i1-2 (MPX1) - iA1-1

Always

Below 1 Ω

*a

Front view of wire harness connector

(to Front Wiper Motor and Link Assembly)

*b

Front view of wire harness connector

(to Wire Harness)
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR
NG

REPLACE WIPER MOTOR WIRE

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