Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Folding Motor Circuit

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

DESCRIPTION

HINT:

  • The rear power seat switch is a collective term for the rear power seat switch RH and the rear power seat switch LH.
  • The rear seatback frame sub-assembly is a collective term for the rear seatback frame sub-assembly RH and the rear seatback frame sub-assembly LH.

The fold seat control ECU receives switch operation signals from the rear power seat switch and fold seat switch assembly operates the fold motor according to the received signal. While the fold motor is operating, its built-in Hall IC detects the position of the rear seatback and sends a fold motor position sensor signal to the fold seat control ECU. The fold seat control ECU uses the Hall IC to detect abnormalities, such as if the rear seatback is jammed.

WIRING DIAGRAM

PROCEDURE

1.

INSPECT REAR SEATBACK FRAME SUB-ASSEMBLY (FOLD MOTOR)

(a) Remove the rear seatback frame sub-assembly.

  • for Rear LH Seat: Click here
  • for Rear RH Seat: Click here

(b) Inspect the rear seatback frame sub-assembly (fold motor).

  • for Rear LH Seat: Click here
  • for Rear RH Seat: Click here
NG

REPLACE REAR SEATBACK FRAME SUB-ASSEMBLY

OK

2.

CHECK HARNESS AND CONNECTOR (FOLD SEAT CONTROL ECU - FOLD MOTOR)

(a) Disconnect the x3*1 or y3*2 and x4*1 or y4*2 fold seat control ECU (rear RH seat) connectors.

  • *1: for Rear RH Seat
  • *2: for Rear LH Seat

(b) Disconnect the x2*1 or y1*2 fold motor connector.

  • *1: for Rear RH Seat
  • *2: for Rear LH Seat

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

Standard Resistance:

for Rear RH Seat

Tester Connection

Condition

Specified Condition

x3-11 (SV1) - x2-5 (HLV)

Always

Below 1 Ω

x3-11 (SV1) or x2-5 (HLV) - Body ground

Always

10 kΩ or higher

x3-10 (SFLD) - x2-2 (HLS)

Always

Below 1 Ω

x3-10 (SFLD) or x2-2 (HLS) - Body ground

Always

10 kΩ or higher

x3-8 (SG1) - x2-6 (HLG)

Always

Below 1 Ω

x3-8 (SG1) or x2-6 (HLG) - Body ground

Always

10 kΩ or higher

x4-4 (FLD+) - x2-3 (FWD)

Always

Below 1 Ω

x4-4 (FLD+) or x2-3 (FWD) - Body ground

Always

10 kΩ or higher

x4-8 (FLD-) - x2-4 (BACK)

Always

Below 1 Ω

x4-8 (FLD-) or x2-4 (BACK) - Body ground

Always

10 kΩ or higher

for Rear LH Seat

Tester Connection

Condition

Specified Condition

y3-11 (SV1) - y1-5 (HLV)

Always

Below 1 Ω

y3-11 (SV1) or y1-5 (HLV) - Body ground

Always

10 kΩ or higher

y3-10 (SFLD) - y1-2 (HLS)

Always

Below 1 Ω

y3-10 (SFLD) or y1-2 (HLS) - Body ground

Always

10 kΩ or higher

y3-8 (SG1) - y1-6 (HLG)

Always

Below 1 Ω

y3-8 (SG1) or y1-6 (HLG) - Body ground

Always

10 kΩ or higher

y4-4 (FLD+) - y1-3 (FWD)

Always

Below 1 Ω

y4-4 (FLD+) or y1-3 (FWD) - Body ground

Always

10 kΩ or higher

y4-8 (FLD-) - y1-4 (BACK)

Always

Below 1 Ω

y4-8 (FLD-) or y1-4 (BACK) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK REAR SEATBACK FRAME SUB-ASSEMBLY (POSITION SENSOR)

(a) Temporarily replace the rear seatback frame sub-assembly with a new or known good one.

  • for Rear LH Seat: Click here
  • for Rear RH Seat: Click here

(b) Check the operation of the rear power seat.

Click here

OK

END (REAR SEATBACK FRAME SUB-ASSEMBLY WAS DEFECTIVE)
NG

REPLACE FOLD SEAT CONTROL ECU

    Power Source Circuit
    DESCRIPTION Power is supplied to the fold seat control ECU through the ECU-DCC NO. 2, P/SEAT R/R*1, P/SEAT R/L*2 and ECU-IG1 NO. 4 fuses. *1: for Rear Right Seat *2: for Rear Left Seat WIRING ...

    Reclining Motor Circuit
    DESCRIPTION HINT: The rear power seat switch is a collective term for the rear power seat switch RH and the rear power seat switch LH. The rear seatback frame sub-assembly is a collective term fo ...

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