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Lexus RX300 (MCU15). Service manual - part 152

I10177

Function Switch

DISC Switch

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BODY ELECTRICAL

AUDIO SYSTEM (Except Europe)

BE–155

LEXUS RX300 (RM785E)

DIAGNOSIS FUNCTION

Error codes over tuner and connected equipment are displayed on the screen of tuner.
HINT:
Press the function switch instead of TRACK TUNE APS switch.
(a)

Diagnosis start–up
For shifting to diagnosis mode, push ”DISC” switch 3 times with pressing ”1” and ”6”,”7” or ”8” of function
switch at the same time while the audio power is OFF and ACC is ON.
To exit from diagnosis mode, press ”DISC” switch for 2 seconds or turn the ignition key OFF.
(When ”1–190” is displayed, the mode is transferred to LAN check mode.)

(b)

LAN check
When starting up the diagnosis mode, the mode turns to LAN check mode, the screen displays the
code numbers (physical address) of tuner and connected equipment. Smaller codes are displayed in
order, displayed code numbers are switched by operating TUNE ”UP” or ”DOWN” switch. In LAN check
mode, by pressing ”5” of function switch for more than 2 secs., diagnosis memory of each equipment
can be deleted, when deletion is completed, the mode returns to LAN check mode.

Code No. (physical address) List

Code No. (physical address)

Equipment name

190

Radio receiver assembly (Audio head unit)

1c4

Center Cluster Integration Switch

1d4

Multi Display

240

CD changer (in Luggage room)

360

CD changer(in center console and glove compartment box)

440

Power amplifier

H: This shows the equipment has a diagnosis code.

190: Physical address

1: This is the number allotted to the diagnosis code
that occurred.

21: DTC No.

Last Code No.

: NO DTC No.

Pressing TURN ”DOWN”

Pressing TURN ”UP”

1: This is the number allotted to the diagnosis code
that occurred.

BE–156

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BODY ELECTRICAL

AUDIO SYSTEM (Except Europe)

LEXUS RX300 (RM785E)

(c)

System check
When pressing ”1” of function switch in LAN check mode, the mode turns to the system check mode,
the system performs self diagnosis of connected equipment and displays the results.(”SYS” (showing
the system is under detection) is displayed.)

Perform the operation shown in the following illustration, then read the result of the inspection.
HINT:

It sometimes takes approx. 40 secs. till the system inspection is completed.

The chart below is an example of when diagnosis code ”21” appears on the physical address (190)
equipment. (ROM error occurs on the radio receiver.)

The smaller code numbers (physical address) are displayed in order (code No., diagnosis code, sup-
port code of diagnosis code (object equipment)).

When no error is detected in the system, ”00” is displayed.

When an error code is detected, up to 6 codes per one system are displayed. Pressing TUNE ”UP”
or ”DOWN” switches the display.

In the system check mode, when pressing ”8” of function switch the mode returns to LAN check mode.

(d)

Diagnosis memory
(1)

In LAN check mode, when pressing ”2” of TRACK TUNE APS switch the mode turns to the diag-
nosis memory mode. (”CODE” is displayed.)
The results of self diagnosis performed over tuner and connected equipment are memorized and
displayed.

(2)

Perform the operation shown in the following illustration, then read the result of the inspection.

HINT:

The smaller code numbers (physical address) are displayed in order (code No. , periodic communica-
tion number when error occurs, diagnosis code, and support code of diagnosis code (object equip-
ment)).

When no error is detected in the system, ”00” is displayed. When an error code is detected, up to 6
codes per one system are displayed. Pressing TUNE ”UP” or ”DOWN” switches the display. Each diag-
nosis code is same as code in the system check mode.

When pressing ”8” of function switch, the mode returns to LAN check mode.

H: This shows the equipment has a diagnosis code.
190: Physical address

1: This is the number allotted to the diagnosis code
that occurred.

Last Code No.

06: Periodic communication number of when
occurring in the diagnosis memory code.

Pressing TURN ”DOWN”

Pressing TURN ”UP”

21: Periodic communication number of when
occurring in the diagnosis memory code.

1: This is the number allotted to the diagnosis code
that occurred.
d1: DTC No.

1: This is the number allotted to the diagnosis code
that occurred.
360: Physical address

(Equipment that is communicating code)

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BODY ELECTRICAL

AUDIO SYSTEM (Except Europe)

BE–157

LEXUS RX300 (RM785E)

The following illustration below is an example of when diagnosis code ”D1” appears on the code (190)
and (240 or 360) equipment. (Communication error occurs between the radio receiver and CD chang-
er.)

(e)

Diagnosis memory clear
(1)

After error is fixed, start up the diagnosis mode.

(2)

Continue pressing TRACK TURN APS switch ”5” for 2 secs. (CLr is displayed.)

(3)

Press the TRACK TURN APS switch ”2” and transfer to the diagnosis memory mode and check
that the normal code (00) is output.

DTC

Diagnosis item

Diagnosis content

Countermeasure
and inspected parts

AM tuner error

There is an error in AM tuner.Radio receiver check.

FM tuner error

50 Cassette error

Transmitter error

Periodic
communication error

Diagnosis no response

CD error

61 EJECT error

DISC inside out/flaw

Pickup temperature
detection
Excessive current
detection

Tray insertion/
discharging error

There is an error in FM tuner.

There is an error in cassette
deck.

Communication with the
equipment that is
communicating has failed
successively.

Connection confirmation
has not come from the
equipment that is
communicating

Result of diagnosis is not
issued from start to finish.

Error codes other than
61–69 are detected.

CD is not ejected.

CD is inserted inside
out or it has a flaw.

High temperature of CD
changer is detected.

Excessive current to
CD changer is detected.

An error occurs in insertion
and discharging operation of
CD changer tray.

Radio receiver check.

CD changer check.

CD changer check.
Magazine check.

CD check.

CD changer check.

CD changer check.
Magazine check.

Radio receiver check.
Wire harness and
connecter check.

CD
(240)
(360)

System
Check

Diagnosis

memory

Head
Unit
(190)

Parts
Name

ROM error

RAM error

There is an error on
internal ROM.

There is an error on
internal RAM.

51 Cassette eject error

Cassette can not be ejected
from Head Unit.

ROM error

RAM error

There is an error on
internal ROM.

There is an error on
internal RAM.

Periodic
communication
no response

Error in periodic
communication.

D Wire harness and
connector

D Radio receiver check.
D Wire harness check.

BE–158

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BODY ELECTRICAL

AUDIO SYSTEM (Except Europe)

LEXUS RX300 (RM785E)

DIAGNOSIS CODE LIST

If there is ”O” in the column of system check, an error can be detected when the mode is switched to
the system check mode.

If there is ”O” in the column of diagnosis mode, each unit is monitring whether or not it has failure. In
case of detecting failure, it memorizes DTC.

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