Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Terminals Of Ecu

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

TERMINALS OF ECU

CHECK FOLD SEAT CONTROL ECU RH

(a) Disconnect the x3 and x4 fold seat control ECU RH connectors.

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

Terminal No.

(Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

x3-1 (ECUB) - Body ground

W - Body ground

Battery power supply

Always

11 to 14 V

x3-3 (IG) - Body ground

B - Body ground

IG power supply

Engine switch on (IG)

11 to 14 V

Engine switch off

Below 1 V

x3-40 (IND2) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

x4-1 (IND1) - Body ground

B - Body ground

Battery power supply

Always

11 to 14 V

x4-2 (+B) - Body ground

W - Body ground

Battery power supply

Always

11 to 14 V

x4-9 (GND2) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

x4-10 (GND) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

(c) Reconnect the x3 and x4 fold seat control ECU RH connectors.

(d) Measure the resistance and voltage and check for pulses according to the value(s) in the table below.

Terminal No.

(Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

x3-7 (RCLR) - Body ground

SB - Body ground

Rear power seat switch RH (return switch) signal

Rear power seat switch RH off → on (return)

11 to 14 V → Below 1 V

x3-8 (SG1) - Body ground

G - Body ground

Ground

Always

Below 1 Ω

x3-10 (SFLD) - x3-8 (SG1)

P - G

Fold motor position sensor signal

Motor operating

Pulse generation

x3-11 (SV1) - x3-8 (SG1)

R - G

Fold motor position sensor power supply

Engine switch off → on (IG)

Below 1 V → 5.5 to 8 V

x3-12 (RCLF) - Body ground

G - Body ground

Rear power seat switch RH (fold switch) signal

Rear power seat switch RH off → on (fold)

11 to 14 V → Below 1 V

x3-17 (P) - Body ground

GR - Body ground

Driving condition signal
  • Engine switch on (IG), shift lever in P → not in P
  • Engine switch on (IG), stop light switch assembly on → off
  • Engine switch on (IG), parking brake applied → released

11 to 14 V → Below 1 V

Engine switch off

11 to 14 V

x3-18 (R CL) - Body ground

P - Body ground

Rear door courtesy light switch assembly RH signal

Rear door RH opened → closed

11 to 14 V → Below 1 V

x3-19 (BDCY) - Body ground

R - Body ground

Back door courtesy light switch assembly signal

Back door opened → closed

11 to 14 V → Below 1 V

x3-25 (RTRN) - Body ground

B - Body ground

Fold seat switch assembly (return switch) signal (for Rear Right Seat)

Fold seat switch assembly (for Rear Right Seat) off → on (return)

11 to 14 V → Below 1 V

x3-26 (FOLD) - Body ground

L - Body ground

Fold seat switch assembly (fold switch) signal (for Rear Right Seat)

Fold seat switch assembly (for Rear Right Seat) off → on (fold)

11 to 14 V → Below 1 V

x4-3 (RCL+) - Body ground

P - Body ground

Reclining motor operation signal

Rear power seat switch RH off → on (fold)

Below 1 V → 11 to 14 V

x4-4 (FLD+) - Body ground

L - Body ground

Fold motor operation signal

Rear power seat switch RH or Fold seat switch assembly (for Rear Right Seat) off → on (fold)

Below 1 V → 11 to 14 V

x4-7 (RCL-) - Body ground

LG - Body ground

Reclining motor operation signal

Rear power seat switch RH off → on (return)

Below 1 V → 11 to 14 V

x4-8 (FLD-) - Body ground

SB - Body ground

Return motor operation signal

Rear power seat switch RH or Fold seat switch assembly (for Rear Right Seat) off → on (return)

Below 1 V → 11 to 14 V

CHECK FOLD SEAT CONTROL ECU LH

(a) Disconnect the y3 and y4 fold seat control ECU LH connectors.

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

Terminal No.

(Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

y3-1 (ECUB) - Body ground

W - Body ground

Battery power supply

Engine switch on (IG)

11 to 14 V

y3-3 (IG) - Body ground

B - Body ground

IG power supply

Engine switch on (IG)

11 to 14 V

Engine switch off

Below 1 V

y3-40 (IND2) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

y4-1 (IND1) - Body ground

B - Body ground

Battery power supply

Always

11 to 14 V

y4-2 (+B) - Body ground

W - Body ground

Battery power supply

Always

11 to 14 V

y4-9 (GND2) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

y4-10 (GND) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

(c) Reconnect the y3 and y4 fold seat control ECU LH connectors.

(d) Measure the resistance and voltage and check for pulses according to the value(s) in the table below.

Terminal No.

(Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

y3-7 (RCLR) - Body ground

SB - Body ground

Rear power seat switch signal LH (return switch) signal

Rear power seat switch LH off → on (return)

11 to 14 V → Below 1 V

y3-8 (SG1) - Body ground

G - Body ground

Ground

Always

Below 1 Ω

y3-10 (SFLD) - y3-8 (SG1)

P - G

Fold motor position sensor signal

Motor operating

Pulse generation

y3-11 (SV1) - y3-8 (SG1)

R - G

Fold motor position sensor power supply

Engine switch off → on (IG)

Below 1 V → 5.5 to 8 V

y3-12 (RCLF) - Body ground

G - Body ground

Rear power seat switch LH (fold switch) signal

Rear power seat switch LH off → on (fold)

11 to 14 V → Below 1 V

y3-17 (P) - Body ground

GR - Body ground

Driving condition signal
  • Engine switch on (IG), shift lever in P → not in P
  • Engine switch on (IG), stop light switch assembly on → off
  • Engine switch on (IG), parking brake applied → released

11 to 14 V → Below 1 V

Engine switch off

11 to 14 V

y3-18 (R CL) - Body ground

P - Body ground

Rear door courtesy light switch assembly LH signal

Rear door LH opened → closed

11 to 14 V → Below 1 V

y3-19 (BDCY) - Body ground

R - Body ground

Back door courtesy light switch assembly signal

Back door opened → closed

11 to 14 V → Below 1 V

y3-25 (RTRN) - Body ground

B - Body ground

Fold seat switch assembly (fold switch) signal (for Rear Left Seat)

Fold seat switch assembly (for Rear Left Seat) off → on (return)

11 to 14 V → Below 1 V

y3-26 (FOLD) - Body ground

L - Body ground

Fold seat switch assembly (fold switch) signal (for Rear Left Seat)

Fold seat switch assembly (for Rear Left Seat) off → on (fold)

11 to 14 V → Below 1 V

y4-3 (RCL+) - Body ground

P - Body ground

Reclining motor operation signal

Rear power seat switch LH off → on (fold)

Below 1 V → 11 to 14 V

y4-4 (FLD+) - Body ground

L - Body ground

Fold motor operation signal

Rear power seat switch LH or Fold seat switch assembly (for Rear Left Seat) off → on (fold)

Below 1 V → 11 to 14 V

y4-7 (RCL-) - Body ground

LG - Body ground

Reclining motor operation signal

Rear power seat switch LH off → on (return)

Below 1 V → 11 to 14 V

y4-8 (FLD-) - Body ground

SB - Body ground

Return motor operation signal

Rear power seat switch LH or Fold seat switch assembly (for Rear Left Seat) off → on (return)

Below 1 V → 11 to 14 V
    Operation Check
    OPERATION CHECK CHECK BASIC FUNCTION HINT: The rear power seat switch is a collective term for the rear power seat switch RH and the rear power seat switch LH. (a) Operate the rear power seat switch, ...

    Back Door Courtesy Switch Circuit
    DESCRIPTION The fold seat control ECU receives switch operation signals, the driving condition signal and back door courtesy light switch assembly signal and operates the rear power seat according to ...

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