Lexus RX300 (MCU15). Manual - part 385

DI–770

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DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

LEXUS RX300   (RM785E)

9. Black screen appears when ”Present Location”, ”Menu” or ”Set
Designation” switch pressed.

INSPECTION PROCEDURE

1

Check the navigation ECU.

CHECK:
Check terminals +B.
OK:

+B: 10 – 14 V

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

ACC: 10 – 14 V

CHECK:
Check terminal R, G, B, VR or VG.
OK:

R, G, B, VR or VG: See ”Navigation ECU” of ”TERMINAL OF ECU”

NG

Replace the wire harness when all terminals are
faulty. Replace the wire harness when SYNC ter-
minal is faulty.

OK

Replace the multi display.

DI7P2–02

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DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

DI–771

LEXUS RX300   (RM785E)

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

INSPECTION PROCEDURE

1

Check the radio receiver assembly.

PREPARATION:
Disconnect the radio receiver assembly 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 radio receiver assembly.

DI7P3–02

DI–772

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DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

LEXUS RX300   (RM785E)

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

INSPECTION PROCEDURE

1

Service check mode.

NG

Troubleshoot for each diagnosis.

OK

2

Check wire harness (between navigation ECU and radio receiver assembly).

PREPARATION:
Disconnect the navigation ECU and radio receiver assembly connector.
CHECK:
(a)

Check continuity between terminal AUI+ of navigation ECU connector and terminal FL+ of radio receiv-
er assembly.

(b)

Check continuity between terminal AUI– of navigation ECU connector and terminal FL– of radio receiv-
er assembly.

OK:

Continuity

NG

Replace or repair wire harness.

OK

3

Check the navigation system voice.

OK

Go to step 6.

NG

DI7P4–02

–

DIAGNOSTICS

LEXUS NAVIGATION SYSTEM

DI–773

LEXUS RX300   (RM785E)

4

Check wire harness (between navigation ECU and driver side door speaker).

PREPARATION:
Disconnect the navigation ECU and driver side door speaker connector.
CHECK:
(a)

Check continuity between terminal AUO+ of navigation ECU connector and terminal 1 of driver side
door speaker.

(b)

Check continuity between terminal AUO– of navigation ECU connector and terminal 2 of driver side
door speaker.

OK:

Continuity

NG

Replace or repair wire harness.

OK

5

Check the driver side door speaker.

NG

Replace the speaker.

OK

Replace the navigation ECU.

6

Check the navigation ECU.

CHECK:
Check terminal AUO+, AUO–, AUI+ and AUI–.
OK:

AUO+, AUO–, AUI+ and AUI–: See ”Navigation ECU” of ”TERMINAL OF ECU”.

NG

Replace the navigation ECU.

OK

Replace the radio receiver assembly.