Lexus NX: Fold Seat Switch Circuit

DESCRIPTION

When the fold seat switch is operated, a switch operation signal is sent to the fold seat control ECU. The ECU receives switch operation signals from each switch and activates the reclining motor and cushion motor.

WIRING DIAGRAM

PROCEDURE

1.

CHECK FOLD SEAT CONTROL ECU (FOLD SEAT SWITCH SIGNAL)

(a) Check the No. 1 fold seat switch signal.

(1) Remove the fold seat control ECU with its connectors still connected.

Click here

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

Standard Voltage:

Rear Right Seat

Tester Connection

Condition

Specified Condition

h3-14 (FLD2) - Body ground

Fold switch of No. 1 fold seat switch (for Rear Right Switch) off → on

11 to 14 V → Below 1 V

h3-13 (RTN2) - Body ground

Return switch of No. 1 fold seat switch (for Rear Right Switch) off → on

11 to 14 V → Below 1 V

Rear Left Seat

Tester Connection

Condition

Specified Condition

i3-14 (FLD2) - Body ground

Fold switch of No. 1 fold seat switch (for Rear Left Switch) off → on

11 to 14 V → Below 1 V

i3-13 (RTN2) - Body ground

Return switch of No. 1 fold seat switch (for Rear Left Switch) off → on

11 to 14 V → Below 1 V

*A

Rear Right Seat

*B

Rear Left Seat

*a

Component with harness connected (Fold Seat Control ECU)

(b) Check No. 2 fold seat switch signal.

(1) Remove the fold seat control ECU with its connectors still connected.

Click here

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

Standard Voltage:

Rear Right Seat

Tester Connection

Condition

Specified Condition

h3-26 (FOLD) - Body ground

Fold switch of No. 2 fold seat switch (for Rear Right Switch) off → on

11 to 14 V → Below 1 V

h3-25 (RTRN) - Body ground

Return switch of No. 2 fold seat switch (for Rear Right Switch) off → on

11 to 14 V → Below 1 V

Rear Left Seat

Tester Connection

Condition

Specified Condition

i3-26 (FOLD) - Body ground

Fold switch of No. 2 fold seat switch (for Rear Left Switch) off → on

11 to 14 V → Below 1 V

i3-25 (RTRN) - Body ground

Return switch of No. 2 fold seat switch (for Rear Left Switch) off → on

11 to 14 V → Below 1 V

Result

Proceed to

OK

A

NG (No. 1 fold seat switch)

B

NG (No. 2 fold seat switch)

C

*A

Rear Right Seat

*B

Rear Left Seat

*a

Component with harness connected (Fold Seat Control ECU)

A

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

C

GO TO STEP 4

B

2.

INSPECT NO. 1 FOLD SEAT SWITCH ASSEMBLY

(a) Remove the No. 1 fold seat switch assembly.

Click here

(b) Inspect the No. 1 fold seat switch assembly.

Click here

NG

REPLACE NO. 1 FOLD SEAT SWITCH ASSEMBLY

OK

3.

CHECK HARNESS AND CONNECTOR (NO. 1 FOLD SEAT SWITCH ASSEMBLY - FOLD SEAT CONTROL ECU AND BODY GROUND)

(a) Disconnect the I17 No. 1 fold seat switch assembly connector.

(b) Disconnect the h3*1 or i3*2 ECU connector.

  • *1: Rear Right Seat
  • *2: Rear Left Seat

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

Standard Resistance:

Rear Right Seat

Tester Connection

Condition

Specified Condition

I17-6 (HFSR) - h3-14 (FLD2)

Always

Below 1 Ω

I17-6 (HFSR) or h3-14 (FLD2) - Body ground

Always

10 kΩ or higher

I17-1 (HRSR) - h3-13 (RTN2)

Always

Below 1 Ω

I17-1 (HRSR) or h3-13 (RTN2) - Body ground

Always

10 kΩ or higher

I17-7 (E) - Body ground

Always

Below 1 Ω

Rear Left Seat

Tester Connection

Condition

Specified Condition

I17-8 (HFSL) - i3-14 (FLD2)

Always

Below 1 Ω

I17-8 (HFSL) or i3-14 (FLD2) - Body ground

Always

10 kΩ or higher

I17-3 (HRSL) - i3-13 (RTN2)

Always

Below 1 Ω

I17-3 (HRSL) or i3-13 (RTN2) - Body ground

Always

10 kΩ or higher

I17-7 (E) - Body ground

Always

Below 1 Ω

OK

REPLACE FOLD SEAT CONTROL ECU

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.

INSPECT NO. 2 FOLD SEAT SWITCH ASSEMBLY

(a) Remove the No. 2 fold seat switch assembly.

Click here

(b) Inspect the No. 2 fold seat switch assembly.

Click here

NG

REPLACE NO. 2 FOLD SEAT SWITCH ASSEMBLY

OK

5.

CHECK HARNESS AND CONNECTOR (NO. 2 FOLD SEAT SWITCH ASSEMBLY - FOLD SEAT CONTROL ECU AND BODY GROUND)

(a) Disconnect the P16 No. 2 fold seat switch assembly connector.

(b) Disconnect the h3*1 or i3*2 fold seat control ECU connector.

  • *1: Rear Right Seat
  • *2: Rear Left Seat

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

Standard Resistance:

Rear Right Seat

Tester Connection

Condition

Specified Condition

P16-6 (FOLD) - h3-26 (FOLD)

Always

Below 1 Ω

P16-6 (FOLD) or h3-26 (FOLD) - Body ground

Always

10 kΩ or higher

P16-1 (RTRN) - h3-25 (RTRN)

Always

Below 1 Ω

P16-1 (RTRN) or h3-25 (RTRN) - Body ground

Always

10 kΩ or higher

P16-7 (E) - Body ground

Always

Below 1 Ω

Rear Left Seat

Tester Connection

Condition

Specified Condition

P16-8 (FOLD) - i3-26 (FOLD)

Always

Below 1 Ω

P16-8 (FOLD) or i3-26 (FOLD) - Body ground

Always

10 kΩ or higher

P16-3 (RTRN) - i3-25 (RTRN)

Always

Below 1 Ω

P16-3 (RTRN) or i3-25 (RTRN) - Body ground

Always

10 kΩ or higher

P16-7 (E) - Body ground

Always

Below 1 Ω

OK

REPLACE FOLD SEAT CONTROL ECU

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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