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

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Vehicle Interior / Seat / Front Power Seat Control System (w/ Memory) / Terminals Of Ecu

TERMINALS OF ECU

CHECK POSITION CONTROL ECU AND SWITCH ASSEMBLY LH

(a) Disconnect the c5 and c6 position control ECU and switch assembly LH connectors.

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

HINT:

Measure the values on the wire harness side with the connector disconnected.

Tester Connection

Wiring Color

Terminal Description

Condition

Specified Condition

c5-2 (GND) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

c5-7 (+B) - c5-2 (GND)

W*1, R*2 - W-B

Battery power supply

Always

11 to 14 V

c6-12 (SYSB) - c5-2 (GND)

P - W-B

System power source

Always

11 to 14 V

c6-3 (IG) - c5-2 (GND)

R - W-B

Ignition power supply

Engine switch on (IG)

11 to 14 V

c6-3 (IG) - c5-2 (GND)

R - W-B

Ignition power supply

Engine switch off

Below 1 V

c6-10 (DBCL) - Body ground

GR - Body ground

Driver seat belt buckle switch signal

Driver seat belt fastened

Below 1 Ω

c6-10 (DBCL) - Body ground

GR - Body ground

Driver seat belt buckle switch signal

Driver seat belt unfastened

10 kΩ or higher
  • *1: w/o Seat VariableCushion Switch
  • *2: w/ Seat VariableCushion Switch

(c) Reconnect the c5 and c6 position control ECU and switch assembly LH connectors.

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

Tester Connection

Wiring Color

Terminal Description

Condition

Specified Condition

c5-6 (+B2) - c5-2 (GND)

SB - W-B

Lumbar support adjuster power source

Always

11 to 14 V

c5-1 (GND2) - Body ground

W-B - Body ground

Lumbar support adjuster ground

Always

Below 1 Ω

c5-3 (SLD+) - c5-2 (GND)

L - W-B

Slide motor signal (forward)

Slide switch off

Below 1 V

Slide switch on (Forward)

11 to 14 V

c5-4 (SLD-) - c5-2 (GND)

GR - W-B

Slide motor signal (rearward)

Slide switch off

Below 1 V

Slide switch on (Rearward)

11 to 14 V

c5-5 (FRV-) - c5-2 (GND)

R - W-B

Front vertical motor signal (downward)

Front vertical switch off

Below 1 V

Front vertical switch on (Downward)

11 to 14 V

c5-8 (FRV+) - c5-2 (GND)

B - W-B

Front vertical motor signal (upward)

Front vertical switch off

Below 1 V

Front vertical switch on (Upward)

11 to 14 V

c5-9 (RCL+) - c5-2 (GND)

P - W-B

Reclining motor signal (forward)

Reclining switch off

Below 1 V

Reclining switch on (Forward)

11 to 14 V

c5-11 (RCL-) - c5-2 (GND)

LG - W-B

Reclining motor signal (rearward)

Reclining switch off

Below 1 V

Reclining switch on (Rearward)

11 to 14 V

c5-10 (LFT+) - c5-2 (GND)

V - W-B

Lifter motor signal (upward)

Lifter switch off

Below 1 V

Lifter switch on (Upward)

11 to 14 V

c5-12 (LFT-) - c5-2 (GND)

G - W-B

Lifter motor signal (downward)

Lifter switch off

Below 1 V

Lifter switch on (Downward)

11 to 14 V

c6-1 (SGND) - c5-2 (GND)

BR - W-B

Position sensor ground

Always

Below 1 Ω

c6-5 (SSRS) - c6-1 (SGND)

G- BR

Slide position signal

Slide function operating

4.8 to 5.1 V

CHECK OUTER MIRROR CONTROL ECU ASSEMBLY (DRIVER DOOR)

(a) Disconnect the N4 outer mirror control ECU assembly (driver door) connector.

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

HINT:

Measure the values on the wire harness side with the connector disconnected.

Tester Connection

Wiring Color

Terminal Description

Condition

Specified Condition

N4-6 (CPUB) - N4-7 (GND)

L - W-B

Battery power supply

Always

11 to 14 V

N4-14 (BDR) - N4-7 (GND)

L - W-B

Battery power supply

Always

11 to 14 V

N4-5 (SIG) - N4-7 (GND)

Y - W-B

Ignition power supply

Engine switch on (IG)

11 to 14 V

N4-5 (SIG) - N4-7 (GND)

Y - W-B

Ignition power supply

Always

Below 1 V

N4-7 (GND) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

(c) Reconnect the N4 outer mirror control ECU assembly (driver door) connector.

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

Tester Connection

Wiring Color

Terminal Description

Condition

Specified Condition

N4-1 (MM) - N4-7 (GND)

W - W-B

SET switch signal for seat memory switch LH

SET switch on

Below 1 V

SET switch off

11 to 14 V

N4-2 (M1) - N4-7 (GND)

G - W-B

M1 switch signal for seat memory switch LH

M1 switch on

Below 1 V

M1 switch off

11 to 14 V

N4-3 (M2) - N4-7 (GND)

V - W-B

M2 switch signal for seat memory switch LH

M2 switch on

Below 1 V

M2 switch off

11 to 14 V

N4-4 (M3) - N4-7 (GND)

R - W-B

M3 switch signal for seat memory switch LH

M3 switch on

Below 1 V

M3 switch off

11 to 14 V

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

(a) Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

Click here

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

HINT:

Measure the values on the wire harness side with the connector disconnected.

Tester Connection

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

-

Ignition power supply

Engine switch on (IG)

11 to 14 V

MB-32 (IG) - Body ground

-

Ignition power supply

Engine switch off

Below 1 V

MB-30 (ACC) - Body ground

-

Ignition power supply

Engine switch on (ACC)

11 to 14 V

MB-30 (ACC) - Body ground

-

Ignition power supply

Engine switch off

Below 1 V

MB-11 (GND1) - Body ground

-

Ground

Always

Below 1 Ω

J8-6 (FLCY) - Body ground

P - Body ground

Front door courtesy light switch assembly (driver door) input

Front door LH closed (OFF) → open (ON)

10 kΩ or higher → Below 1 Ω

If the result is not as specified, there may be a malfunction in the wire harness.

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