Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Park / Neutral Position Switch Circuit

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

DESCRIPTION

Each fold seat control ECU receives the driving condition signal and engine switch signal from the main body ECU (multiplex network body ECU) to determine the driving state of the vehicle and enable or disable the fold and return functions.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Before replacing the main body ECU (multiplex network body ECU), refer to registration.
  • When a fold seat control ECU (RH/LH seat) is replaced, it is necessary to perform initialization.

    Click here

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 4

C

GO TO STEP 6

A

2.

CHECK HARNESS AND CONNECTOR (FOLD SEAT CONTROL ECU (RH/LH SEAT) - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))

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

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

(c) Disconnect the J9 main body ECU (multiplex network body ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

x15-17 (P) or y15-17 (P) - J9-16 (SFTP)

Always

Below 1 Ω

x15-17 (P), y15-17 (P) or J9-16 (SFTP) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

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

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

(c) Reconnect the J9 main body ECU (multiplex network body ECU) connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

J9-16 (SFTP) - Body ground

Any of the following conditions are met:

  • Engine switch off
  • Engine switch on (IG) and vehicle speed 5 km/h (3.1 mph) or more
  • Engine switch on (IG), shift lever not in P, brake pedal not depressed and parking brake released

11 to 14 V

Engine switch is on (IG) and any of the following conditions are met:

  • Vehicle speed below 5 km/h (3.1 mph) and shift lever in P
  • Vehicle speed below 5 km/h (3.1 mph) and brake pedal depressed
  • Vehicle speed below 5 km/h (3.1 mph) and parking brake applied

Below 1 V

*a

Component with harness connected

(Main Body ECU (Multiplex Network Body ECU))
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

4.

CHECK FOLD SEAT CONTROL ECU (RH SEAT)

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

(b) Disconnect the J9 main body ECU (multiplex network body ECU) connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

J9-16 (SFTP) - Body ground

Always

11 to 14 V
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

5.

CHECK HARNESS AND CONNECTOR (FOLD SEAT CONTROL ECU (RH SEAT) - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))

(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

x15-17 (P) - J9-16 (SFTP)

Always

Below 1 Ω
OK

REPLACE FOLD SEAT CONTROL ECU (RH SEAT)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.

CHECK FOLD SEAT CONTROL ECU (LH SEAT)

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

(b) Disconnect the J9 main body ECU (multiplex network body ECU) connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

J9-16 (SFTP) - Body ground

Always

11 to 14 V
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

7.

CHECK HARNESS AND CONNECTOR (FOLD SEAT CONTROL ECU (LH SEAT) - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))

(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

y15-17 (P) - J9-16 (SFTP)

Always

Below 1 Ω
OK

REPLACE FOLD SEAT CONTROL ECU (LH SEAT)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
    IG Signal Circuit
    DESCRIPTION Based on the engine switch signal, each fold seat control ECU determines the driving condition of the vehicle and enables or disables the fold and return functions. WIRING DIAGRAM CAUTION ...

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