Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Power Source Circuit

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Vehicle Interior / Seat / Rear Power Seat Control System(for Third Row) / Power Source Circuit

DESCRIPTION

Power is supplied to each fold seat control ECU through fuses.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

CHECK REAR POWER SEAT CONTROL SYSTEM (for Third Row)

(a) Check that the rear power seat control system (for Third Row) function operates normally.

Result

Proceed to

Fold/Return functions of both rear No .2 power seats do not operate normally.

A

Fold/Return functions of rear No. 2 power seat RH do not operate normally.

B

Fold/Return functions of rear No. 2 power seat LH do not operate normally.

C
B

GO TO STEP 5

C

GO TO STEP 8

A

2.

CHECK HARNESS AND CONNECTOR (BATTERY POWER SUPPLY)

(a) Disconnect the 2C instrument panel junction block assembly connector

*a

Front view of wire harness connector

(Instrument panel junction block assembly)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

2C-1 - Body ground

Always

11 to 14 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK HARNESS AND CONNECTOR (BATTERY POWER SUPPLY)

(a) Disconnect the x15 fold seat control ECU (RH seat) connector.

*A

for RH seat

*B

for LH seat

*a

Front view of wire harness connector

(Fold Seat Control ECU (RH/LH Seat))

(b) Disconnect the y15 fold seat control ECU (LH seat) connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

x15-1 (ECUB) - Body ground

Always

11 to 14 V

y15-1 (ECUB) - Body ground

Always

11 to 14 V
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

4.

CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - FOLD SEAT CONTROL ECU (RH/LH SEAT))

(a) Disconnect the 2B and 2D instrument panel junction block assembly connector

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

2B-22 or x15-1 (ECUB) - Body ground

Always

10 kΩ or higher

2D-29 or y15-1 (ECUB) - Body ground

Always

10 kΩ or higher
OK

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.

INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

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

*a

Component with harness connected

(Instrument Panel Junction Block Assembly)

-

-

Standard Voltage:

Tester Connection

Condition

Specified Condition

2B-22 - Body ground

Always

11 to 14 V
NG

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

OK

6.

CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - FOLD SEAT CONTROL ECU (RH SEAT))

(a) Disconnect the x15 fold seat control ECU (RH seat) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

2B-22 - x15-1 (ECUB)

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

7.

CHECK HARNESS AND CONNECTOR (FOLD SEAT CONTROL ECU (RH SEAT) - BATTERY POWER SUPPLY AND BODY GROUND)

(a) Disconnect the x16 fold seat control ECU (RH seat) connector.

*a

Front view of wire harness connector

(Fold Seat Control ECU (RH Seat))

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

x16-1 (IND1) - Body ground

Always

11 to 14 V

x16-2 (+B) - Body ground

Always

11 to 14 V

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

x15-40 (IND2) - Body ground

Always

Below 1 Ω

x16-9 (GND2) - Body ground

Always

Below 1 Ω

x16-10 (GND) - Body ground

Always

Below 1 Ω
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

8.

INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

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

*a

Component with harness connected

(Instrument Panel Junction Block Assembly)

-

-

Standard Voltage:

Tester Connection

Condition

Specified Condition

2D-29 - Body ground

Always

11 to 14 V
NG

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

OK

9.

CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - FOLD SEAT CONTROL ECU (LH SEAT))

(a) Disconnect the y15 fold seat control ECU (LH seat) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

y15-1 (ECUB) - 2D-29

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

10.

CHECK HARNESS AND CONNECTOR (FOLD SEAT CONTROL ECU (LH SEAT) - BATTERY POWER SUPPLY AND BODY GROUND)

(a) Disconnect the y16 fold seat control ECU (LH seat) connector.

*a

Front view of wire harness connector

(Fold Seat Control ECU (LH Seat))

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

y16-1 (IND1) - Body ground

Always

11 to 14 V

y16-2 (+B) - Body ground

Always

11 to 14 V

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

y15-40 (IND2) - Body ground

Always

Below 1 Ω

y16-9 (GND2) - Body ground

Always

Below 1 Ω

y16-10 (GND) - Body ground

Always

Below 1 Ω
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
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