Lexus NX: Terminals Of Ecu

TERMINALS OF ECU

CHECK WINDSHIELD WIPER RELAY ASSEMBLY (w/ Rain Sensor)

(a) Disconnect the I56 windshield wiper relay assembly 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.

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

I56-2 (IG) - Body ground

L - Body ground

IG power supply

Power switch on (IG)

11 to 14 V

Power switch off

Below 1 V

I56-8 (VR2) - I56-21 (VR1)

Y - W

Adjusting volume circuit

Windshield wiper switch assembly adjusting ring changed

0 to 231 Ω

I56-12 (E) - Body ground

W-B - Body ground

Body ground

Always

Below 1 Ω

I56-16 (WIG) - Body ground

L - Body ground

IG power supply

Power switch on (IG)

11 to 14 V

Power switch off

Below 1 V

(c) Reconnect the I56 windshield wiper relay assembly connector.

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

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

I56-1 (+SM) - Body ground

G - Body ground

Front wiper motor operation signal

Front wiper motor in low or high operating

11 to 14 V

Front wiper motor not operating

Below 1 V

I56-3 (C1) - I56-5 (C0)

GR - L

Front wiper switch AUTO position signal

Power switch on (IG), windshield wiper switch assembly in AUTO position

Below 1 V

Power switch on (IG), windshield wiper switch assembly in not AUTO position

11 to 14 V

I56-10 (+1) - Body ground

G - Body ground

Front wiper motor low speed signal

Power switch on (IG), front wiper motor in low operating

11 to 14 V

Power switch on (IG), front wiper motor not operating

Below 1 V

I56-11 (+2) - Body ground

R - Body ground

Front wiper motor high speed signal

Power switch on (IG), front wiper motor in high operating

11 to 14 V

Power switch on (IG), front wiper motor not operating

Below 1 V

I56-14 (MPX1) - Body ground

V - Body ground

LIN communication signal

Power switch on (IG)

Pulse generation

Power switch off

Below 1 V

I56-24 (SPD) - Body ground

B - Body ground

Vehicle speed signal

Driving at approximately 20 km/h (12 mph)

Pulse generation (See waveform 1)

I56-25 (W) - Body ground

LA-L - Body ground

Front washer motor signal

Power switch on (IG), front washer switch off

11 to 14 V

Power switch on (IG), front washer switch on

Below 1 V

(1) Waveform 1 (Reference):

Item

Condition

Tester Connection

I56-24 (SPD) - Body ground

Tool Setting

5 V/DIV., 20 ms/DIV.

Vehicle Condition

Driving at approximately 20 km/h (12 mph)

HINT:

When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by A in the illustration narrows.

CHECK RAIN SENSOR (w/ Rain Sensor)

(a) Disconnect the T8 rain sensor connector.

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

HINT:

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

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

T8-4 (SIG) - Body ground

GR - Body ground

IG power supply

Power switch on (IG)

11 to 14 V

Power switch off

Below 1 V

T8-2 (ES) - Body ground

W - Body ground

Body ground

Always

Below 1 Ω

(c) Reconnect the T8 rain sensor connector.

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

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

T8-1 (MPX) - Body ground

V - Body ground

LIN communication signal

Power switch on (IG)

Pulse generation

Power switch off

Below 1 V

CHECK COMBINATION METER ASSEMBLY

(a) Disconnect the I10 combination meter assembly 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.

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

I10-22 (B) - Body ground

Y - Body ground

Auxiliary battery power supply

Power switch off

11 to 14 V

I10-21 (IG+) - Body ground

B - Body ground

IG power supply

Power switch on (IG)

11 to 14 V

Power switch off

Below 1 V

I10-31 (ES) - Body ground

W-B - Body ground

Body ground

Always

Below 1 Ω

(c) Reconnect the I10 combination meter assembly connector.

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

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

I10-16 (WLVL) - Body ground

LG - Body ground

Washer fluid level signal

Power switch on (IG), washer fluid level not low

11 to 14 V

Power switch on (IG), washer fluid level low

Below 1 V

(e) Measure the waveform according to the value(s) in the table below.

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

I10-19 (+S) - Body ground

V - Body ground

Speed signal for other system (Output)

Driving at approximately 20 km/h (12 mph)

Pulse generation (See waveform 1)

(1) Waveform 1 (Reference):

Item

Condition

Tester Connection

I10-19 (+S) - Body ground

Tool Setting

5 V/DIV., 20 ms/DIV.

Vehicle Condition

Driving at approximately 20 km/h (12 mph)

HINT:

When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by A in the illustration narrows.

HEADLIGHT ECU SUB-ASSEMBLY RH (w/ Headlight Cleaner System, for Triple Beam Headlight)

(a) Disconnect the A20 headlight ECU sub-assembly RH connector.

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

HINT:

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

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

A20-4 (IG) - Body ground

G - Body ground

IG power supply

Power switch off

Below 1 V

Power switch on (IG)

11 to 14 V

A20-12 (GND) - Body ground

W-B - Body ground

Body ground

Always

Below 1 Ω

(c) Reconnect the A20 headlight ECU sub-assembly RH connector.

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

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

A20-7 (HLC) - Body ground

R - Body ground

Headlight cleaner motor operation signal

Headlight cleaner motor not operating

11 to 14 V

Headlight cleaner motor operating

Below 1 V

A20-18 (FRWA) - Body ground

B - Body ground

Front washer switch signal

Power switch on (IG), front washer switch on

11 to 14 V

Power switch on (IG), front washer switch off

Below 1 V

CHECK HEADLIGHT CLEANER CONTROL RELAY (w/ Headlight Cleaner System, for Single Beam Headlight)

(a) Disconnect the A65 headlight cleaner control relay 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.

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

A65-1 (HDLO) - Body ground

LG - Body ground

Low beam headlight operation signal

Low beam headlights not operating

11 to 14 V

Low beam headlights operating

Below 1 V

A65-3 (IG) - A65-4 (E)

B - W-B

IG power supply

Power switch on (IG)

11 to 14 V

Power switch off

Below 1 V

A65-4 (E) - Body ground

W-B - Body ground

Body ground

Always

Below 1 Ω

(c) Reconnect the A65 headlight cleaner control relay connector.

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

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

A65-5 (FRWA) - A65-4 (E)

W - W-B

Front washer switch signal

Power switch on (IG), front washer switch on

11 to 14 V

Power switch on (IG), front washer switch off

Below 1 V

A65-6 (+B) - A65-4 (E)

L - W-B

Headlight cleaner motor operation signal

Headlight cleaner motor not operating

11 to 14 V

Headlight cleaner motor operating

Below 1 V

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

*1

Main Body ECU (Multiplex Network Body ECU)

-

-

(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.

Tester Connection

Wiring Color

Terminal Description

Condition

Specified Condition

A-11 (GND1) - Body ground

None - Body ground

Body ground

Always

Below 1 Ω

A-31 (BECU) - Body ground

None - Body ground

Auxiliary battery power supply

Power switch off

11 to 14 V

A-30 (ACC) - Body ground

None - Body ground

ACC power supply

Power switch on (ACC)

11 to 14 V

Power switch off

Below 1 V

A-32 (IG) - Body ground

None - Body ground

IG power supply

Power switch on (IG)

11 to 14 V

Power switch off

Below 1 V

(c) Install the main body ECU (multiplex network body ECU) to the instrument panel junction block assembly.

Click here

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

Tester Connection

Wiring Color

Terminal Description

Condition

Specified Condition

4B-53 (HRLY) - Body ground

L - Body ground

Low beam headlight signal

Light control switch in head position

Below 1 V

Light control switch off

11 to 14 V

READ NEXT:

 Fail-safe Chart

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