Lexus RX300 (MCU15). Manual - part 381

I15499

N2

N3

DI–754

–

DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

LEXUS RX300   (RM785E)

NAVIGATION ECU

Symbols

Condition

STD Voltage (V)

Problem symptom when

open circuit is detected.

Symbols

(Terminals NO. )

Condition

STD Voltage (V)

Problem symptom when

short circuit is detected.

AUI+ ↔ GND

(N2–1 ↔ N2–17)

Radio switch ON

5 – 7 V

Driver’s side speaker does not

sound.

AUO+ ↔ GND

(N2–2 ↔ N2–17)

Radio switch ON

5 – 7 V

Driver’s side speaker does not

sound.

SPD ↔ GND

(N2–5 ↔ N2–17)

Ignition switch ON and driving

wheel rotated slowly

Repeatedly changes from below 1

to 9 V

Navigation operation is available

during, or a cursor on present site

does not move.

+B ↔ GND

(N2–9 ↔ N2–17)

Constant

10 – 14 V

The set route can not be memo-

rized. (The route disappears by

turning the ignition switch OFF.)

Fuse is blown.

AUI– ↔ GND

(N2–10 ↔ N2–17)

Radio switch ON

5 – 7 V

Driver’s side speaker does not

sound.

AUO– ↔ GND

(N2–11 ↔ N2–17)

Radio switch ON

5 – 7 V

Driver’s side speaker does not

sound.

REV ↔ GND

(N2–14 ↔ N2–17)

A/T shift position R

5 V

The direction of advance of the ve-

hicle is different from that of the

cursor.

GND ↔ Body ground

(N2–17 ↔ Body ground)

Constant

Below 1 V

Audio system is normal.

ACC ↔ GND

(N2–18 ↔ N2–17)

Ignition switch ACC or ON

10 – 14 V

Audio system does not sound.

VR ↔ VG

(N3–1 ↔ N3–6)

Constant

Continuity

Screen noise or other types of

noise occur.

(N3 1 ↔ N3 6)

Navigation system does not op-

eration.

R ↔ VG

(N3–2 ↔ N3–6)

Diagnosis display check screen is

white (Using an oscilloscope)

0.7 V ± 0.1 V*1

Screen color turns to blue.

I15531

GND

Oscilloscope

*1: wave1

D Measure terminal: SYNC ↔ GND1
D Measure set: 500 mV/DIV 10 µs/DIV
D Condition: Navigation display is displayed

I15532

GND

*2: wave2

D Measure terminal: R, G, B ↔ GND1
D Measure set: 200 mV/DIV 10 µs/DIV
D Condition: Navigation map is switched

–

DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

DI–755

LEXUS RX300   (RM785E)

+B ↔ GND

(N3–3 ↔ N2–17)

Constant

10 – 14 V

The set route can not be memo-

rized. (The route disappears by

turning the ignition switch OFF.)

Fuse is blown.

B ↔ VG

(N3–3 ↔ N3–6)

Diagnosis display check screen is

white (Using an oscilloscope)

0.7 ± 0.1 V*2

Screen color turns to yellow. 

TX1+ ↔ GND

(N3–5 ↔ N2–17)

Ignition switch ACC or ON

2 – 3 V

Navigation system does not oper-

ate.

VG ↔ GND

(N3–6 ↔ N2–17)

Constant

Continuity

Screen noise or other types of

noise occur.

(N3 6 ↔ N2 17)

Navigation system does not op-

eration.

G ↔ VG

(N3–7 ↔ N3–6)

Diagnosis display check screen is

white (Using an oscilloscope)

0.7 ± 0.1 V*2

Screen color turns to red–purple.

SYNC ↔ VG

(N3–8 ↔ N3–6)

Display ON 

(Using an oscilloscope)

0.5 - 1.3 V*1

Screen is in disorder.

TX1– ↔ GND

(N3–10 ↔ N2–17)

Ignition switch ACC or ON

2 – 3 V

Navigation system does not oper-

ate.

DI282–07

DI–756

–

DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

LEXUS RX300   (RM785E)

PROBLEM SYMPTOMS TABLE

Flow chart No.

Symptom

See page

1

Black screen (Nothing displayed)

DI–757

2

No sound with POWER switch pressed. (”Audio OFF” on audio screen)

DI–758

3

No navigation screen displayed when ”MAP”, ”Menu”, or ”DEST” switch pressed.

(Screen cannot be switched.)

DI–759

4

No corresponding screen displayed when ”Audio” or ”Information” switch pressed.

DI–762

5

No navigation displayed, ”Audio OFF” on audio screen and no audio sound.

DI–763

6

Screen cannot be dimmed in night time.

DI–765

7

Navigation screen not stabilized. (Synchronous error)

DI–767

8

Color on navigation screen is unusual (RGB signal error)

DI–768

9

Black screen appears when ”MAP”, ”Menu” or ”DEST” switch pressed.

DI–770

10

Sound of radio, cassette tape or CD only cannot be heard from speaker.

DI–771

11

No sound (radio, cassette tape, CD) can be heard from driver side door speaker

only.

DI–772

12

Map DISC cannot be inserted.

DI–774

13

MAP screen display does not appear. 

(Disc Caution screen does not change.)

DI–776

14

Map is displayed in white or blue screen. (Switches and vehicle position mark is

displayed.)

DI–777

15

Touch switch does not function. (Navigation screen only)

DI–778

16

The screen cannot change to the night mode color.

DI–780

17

Vehicle position is deviated from correct point badly.

DI–781

18

GPS mark does not appear.

DI–784

19

No voice navigation.

DI–786

20

Vehicle position rotates without control. (Map rotates without control)

DI–787

21

Driving direction is opposite to moving direction of vehicle position mark.

DI–789

22

Radio reception poor.

DI–790

23

Cassette tape cannot be inserted.

DI–791

24

Cassette tape cannot be eject.

DI–792

25

CD cannot be inserted.

DI–794

26

CD cannot be eject.

DI–795

27

No AM. FM or CD screen is displayed.

DI–796

DI7OU–03

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DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

DI–757

LEXUS RX300   (RM785E)

CIRCUIT INSPECTION

1. Black screen (Nothing displayed)

INSPECTION PROCEDURE

1

Check the RADIO No. 2 and DOME fuse.

NG

Replace the fuse.

OK

2

Check multi display.

PREPARATION:
Disconnect the multi display connector.
CHECK:
Check voltage terminals +B.
OK:

+B: 10 – 14 V

CHECK:
Check voltage terminal ACC when turn ignition switch ACC or ON position.
OK:

ACC: 10 – 14 V

CHECK:
Check continuity terminal GND.
OK:

GND: Continuity

NG

Replace or repair wire harness or connector.

OK

Replace the multi display.