Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual: Terminals Of Ecu

Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual / Vehicle Interior / Seat / Rear Power Seat Control System(for Third Row) / Terminals Of Ecu

TERMINALS OF ECU

CHECK FOLD SEAT CONTROL ECU (RH SEAT)

(a) Disconnect the x15 and x16 fold seat control ECU (RH seat) 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

x16-2 (+B) - Body ground

W - Body ground

Battery power supply

Always

11 to 14 V

x16-1 (IND1) - Body ground

B - Body ground

Battery power supply

Always

11 to 14 V

x15-1 (ECUB) - Body ground

W - Body ground

System power source

Always

11 to 14 V

x15-3 (IG) - Body ground

B - Body ground

IG switch signal

Engine switch off

Below 1 V

IG switch signal

Engine switch on (IG)

11 to 14 V

x16-10 (GND) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

x16-9 (GND2) - Body ground

W-B - Body ground

IG switch signal

Always

Below 1 Ω

x15-40 (IND2) - Body ground

W-B - Body ground

System ground

Always

Below 1 Ω

(c) Reconnect the x15 and x16 fold seat control ECU (RH seat) connectors.

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

(e) Using an oscilloscope, check the waveform.

Terminal No.

(Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

x16-4 (FLD+) - Body ground

L - Body ground

Lifter motor operation signal

(Fold)

Fold switch (RH) of fold seat switch assembly or No. 1 fold seat switch assembly released → pushed (Fold operation)

Below 1 V → 11 to 14 V

x16-8 (FLD-) - Body ground

SB - Body ground

Lifter motor operation signal

(Return)

Return switch (RH) of fold seat switch assembly or No. 1 fold seat switch assembly released → pushed (Return operation)

Below 1 V → 11 to 14 V

x15-11 (SV1) - x15-8 (SG1)

R - G

Lifter motor position sensor power source

Engine switch off → Engine switch on (IG)

Below 1 V → 5.5 to 10 V

x15-10 (SFLD) - x15-8 (SG1)

P - G

Lifter motor position sensor signal

Lifter motor (RH) operating (Fold/return operation)

Pulse generation

(Hi: 5.5 to 10 V, Lo: Below 1 V)

x15-8(SG1) - Body ground

G - Body ground

Lifter motor position sensor ground

Always

Below 1 Ω

x16-3 (RCL+) - Body ground

L - Body ground

Reclining motor operation signal

(Fold)

Fold switch (RH) of fold seat switch assembly or No. 1 fold seat switch assembly released → pushed (Fold operation)

Below 1 V → 11 to 14 V

x16-7 (RCL-) - Body ground

SB - Body ground

Reclining motor operation signal

(Fold)

Return switch (RH) of fold seat switch assembly or No. 1 fold seat switch assembly released → pushed (Return operation)

Below 1 V → 11 to 14 V

x15-31 (SV2) - x15-28 (SG2)

R - G

Reclining motor position sensor power source

Engine switch off → Engine switch on (IG)

Below 1 V → 5.5 to 10 V

x15-9 (SRCL) - x15-28 (SG2)

P - G

Reclining motor position sensor signal

Reclining motor (RH) operating (Fold/return operation)

Pulse generation

(Hi: 5.5 to 10 V, Lo: Below 1 V)

x15-28 (SG2) - Body ground

G - Body ground

Reclining motor position sensor ground

Always

Below 1 Ω

x15-25 (RCLR) - Body ground

B - Body ground

Fold seat switch assembly (return switch (RH)) operation signal

Return switch (RH) of fold seat switch assembly released → pushed

11 to 14 V → Below 1 V

x15-26 (RCLF) - Body ground

L - Body ground

Fold seat switch assembly (fold switch (RH)) operation signal

Fold switch (RH) of fold seat switch assembly released → pushed

11 to 14 V → Below 1 V

x15-7 (RTRN) - Body ground

B - Body ground

Fold seat switch assembly (return switch (RH)) operation signal

Return switch (RH) of No. 1 fold seat switch assembly released → pushed

11 to 14 V → Below 1 V

x15-12 (FOLD) - Body ground

L - Body ground

Fold seat switch assembly (fold switch (RH)) operation signal

Fold switch (RH) of No. 1 fold seat switch assembly released → pushed

11 to 14 V → Below 1 V

x15-17 (P) - Body ground

GR - Body ground

Driving condition signal

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

x15-18 (R CL) - Body ground

P - Body ground

Rear door courtesy light switch assembly (RH) input signal

Rear door RH open → closed

Below 1 V → 11 to 14 V

x15-19 (BDCY) - Body ground

R - Body ground

Back door courtesy light switch assembly input signal

Back door open → closed

Below 1 V → 11 to 14 V

CHECK FOLD SEAT CONTROL ECU (LH SEAT)

(a) Disconnect the y15 and y16 fold seat control ECU (LH seat) 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

y16-2 (+B) - Body ground

W - Body ground

Battery power supply

Always

11 to 14 V

y16-1 (IND1) - Body ground

B - Body ground

Battery power supply

Always

11 to 14 V

y15-1 (ECUB) - Body ground

W - Body ground

System power source

Always

11 to 14 V

y15-3 (IG) - Body ground

B - Body ground

IG switch signal

Engine switch off

Below 1 V

Engine switch on (IG)

11 to 14 V

y16-10 (GND) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

y16-9 (GND2) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

y15-40 (IND2) - Body ground

W-B - Body ground

System ground

Always

Below 1 Ω

(c) Reconnect the y15 and y16 fold seat control ECU (LH seat) connectors.

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

(e) Using an oscilloscope, check the waveform.

Terminal No.

(Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

y16-4 (FLD+) - Body ground

L - Body ground

Lifter motor operation signal

(Fold)

Fold switch (LH) of fold seat switch assembly or No. 1 fold seat switch assembly released → pushed (Fold operation)

Below 1 V → 11 to 14 V

y16-8 (FLD-) - Body ground

SB - Body ground

Lifter motor operation signal

(Return)

Return switch (LH) of fold seat switch assembly or No. 1 fold seat switch assembly released → pushed (Return operation)

Below 1 V → 11 to 14 V

y15-11 (SV1) - y15-8 (SG1)

R - G

Lifter motor position sensor power source

Engine switch off → Engine switch on (IG)

Below 1 V → 5.5 to 10 V

y15-10 (SFLD) - y15-8 (SG1)

P - G

Lifter motor position sensor signal

Lifter motor (LH) operating (Fold/return operation)

Pulse generation

(Hi: 5.5 to 10 V, Lo: Below 1 V)

y15-8(SG1) - Body ground

G - Body ground

Lifter motor position sensor ground

Always

Below 1 Ω

y16-3 (RCL+) - Body ground

L - Body ground

Reclining motor operation signal

(Fold)

Fold switch (LH) of fold seat switch assembly or No. 1 fold seat switch assembly released → pushed (Fold operation)

Below 1 V → 11 to 14 V

y16-7 (RCL-) - Body ground

SB - Body ground

Reclining motor operation signal

(Fold)

Return switch (LH) of fold seat switch assembly or No. 1 fold seat switch assembly released → pushed (Return operation)

Below 1 V → 11 to 14 V

y15-31 (SV2) - y15-28 (SG2)

R - B

Reclining motor position sensor power source

Engine switch off → Engine switch on (IG)

Below 1 V → 5.5 to 10 V

y15-9 (SRCL) - y15-28 (SG2)

P - B

Reclining motor position sensor signal

Reclining motor (LH) operating (Fold/return operation)

Pulse generation

(Hi: 5.5 to 10 V, Lo: Below 1 V)

y15-28 (SG2) - Body ground

B - Body ground

Reclining motor position sensor ground

Always

Below 1 Ω

y15-25 (RCLR) - Body ground

B - Body ground

Fold seat switch assembly (return switch (LH)) operation signal

Return switch (LH) of fold seat switch assembly released → pushed

11 to 14 V → Below 1 V

y15-26 (RCLF) - Body ground

L - Body ground

Fold seat switch assembly (fold switch (LH)) operation signal

Fold switch (LH) of fold seat switch assembly released → pushed

11 to 14 V → Below 1 V

y15-7 (RTRN) - Body ground

B - Body ground

Fold seat switch assembly (return switch (LH)) operation signal

Return switch (LH) of No. 1 fold seat switch assembly released → pushed

11 to 14 V → Below 1 V

y15-12 (FOLD) - Body ground

L - Body ground

Fold seat switch assembly (fold switch (LH)) operation signal

Fold switch (LH) of No. 1 fold seat switch assembly released → pushed

11 to 14 V → Below 1 V

y15-17 (P) - Body ground

GR - Body ground

Driving condition signal

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

y15-18 (R CL) - Body ground

P - Body ground

Rear door courtesy light switch assembly (RH) input signal

Rear door RH open → closed

Below 1 V → 11 to 14 V

y15-19 (BDCY) - Body ground

R - Body ground

Back door courtesy light switch assembly input signal

Back door open → closed

Below 1 V → 11 to 14 V

CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) AND INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

(a) Disconnect the MB main body ECU (multiplex network body ECU) connector.

Click here

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

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

MB-31 (BECU) - Body ground

-

Battery power supply

Always

11 to 14 V

MB-32 (IG) - Body ground

-

IG power supply

Engine switch off

Below 1 V

Engine switch on (IG)

11 to 14 V

MB-11 (GND1) - Body ground

-

Ground

Always

Below 1 Ω

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

Click here

(d) Check for pulses according to the value(s) in the table below.

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

J9-16 (SFTP) - Body ground

-

Driving condition signal

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
    Problem Symptoms Table
    PROBLEM SYMPTOMS TABLE NOTICE: When the fold seat control ECU (RH/LH seat) is replaced , it is necessary to perform initialization. Click here HINT: Use the table below to help determine the caus ...

    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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