Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Back Door Courtesy Switch Circuit

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

DESCRIPTION

Each fold seat control ECU receives back door courtesy light switch input signal to determine the state of the back door and enable or disable the fold and return functions.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • 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 POWER BACK DOOR SYSTEM (w/ Outside Door Control Switch)

(a) Check if the power back door system (w/ outside door control switch) operates normally.

Click here

OK:

Power back door system (w/ outside door control switch) operates normally.

NG

GO TO LIGHTING SYSTEM (BACK DOOR COURTESY SWITCH CIRCUIT)

OK

3.

CHECK HARNESS AND CONNECTOR (FOLD SEAT CONTROL ECU (RH/LH SEAT) - BACK DOOR LOCK ASSEMBLY)

(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 Z7 back door lock assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

x15-19 (BDCY) or y15-19 (BDCY) - Z7-8 (CTY)

Always

Below 1 Ω

x15-19 (BDCY), y15-19 (BDCY) or Z7-8 (CTY) - Body ground

Always

10 kΩ or higher
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.

CHECK FOLD SEAT CONTROL ECU (RH SEAT)

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

(b) Disconnect the Z7 back door lock assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

Z7-8 (CTY) - 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) - BACK DOOR LOCK ASSEMBLY)

(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

x15-19 (BDCY) - Z7-8 (CTY)

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 Z7 back door lock assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

Z7-8 (CTY) - 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) - BACK DOOR LOCK ASSEMBLY)

(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

y15-19 (BDCY) - Z7-8 (CTY)

Always

Below 1 Ω
OK

REPLACE FOLD SEAT SWITCH ASSEMBLY (LH SEAT)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
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