Page 87 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-87
INSPECTION PROCEDURE A-5: Communication with the Sunroof-ECU is not Possible.
.
CIRCUIT OPERATION
Power to the sunroof motor assembly is supplied
through fusible link (5).
When the ignition switch (IG2) signal is on, the
sunroof motor assembly is ready to operate.
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
.
TECHNICAL DESCRIPTION (COMMENT)
The power supply circuit or the communication circuit
to the sunroof motor assembly or the sunroof motor
assembly may be defective.
.
TROUBLESHOOTING HINTS
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The sunroof motor assembly may be defective
The ETACS-ECU may be defective
Page 97 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-97
Door ajar warning buzzer
The buzzer is sounded 4 times by the ETACS-ECU to warn the
driver if any door is open when the ignition is switched ON and
the vehicle speed reaches 8 km/h (5 mph) or faster. The buzzer
will continue to sound for 4 times even if the ignition, door sta-
tus, or vehicle speed requirements are not maintained.
NOTE: The warning buzzer can be customized on vehicles
equipped with a multi center display. Refer to P.54B-486.
Multi center display operation tone
center display >
The ETACS-ECU sounds the buzzer when the buzzer signal is
sent from the center display.
Turn-signal lamp buzzer
The ETACS-ECU sounds the buzzer in sync with the turn-sig-
nal lamps or hazard warning lamps.
NOTE: The turn-signal lamp buzzer can be customized on
vehicles equipped with a multi center display (middle grade
type). Refer to P.54B-486.
General circuit diagram for lamp reminder tone alarm function. P.90-111
General circuit diagram for seat belt tone alarm function. P.90-113
Page 98 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-98
54B
INSPECTION PROCEDURE B-2: Tone Alarm: Light Reminder Tone Alarm Function does not Work
Normally.
NOTE: This troubleshooting procedure requires the
use of diagnostic tool MB991958 and SWS monitor
kit MB991813. For details on how to use the SWS
monitor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
The ETACS-ECU operates the light reminder tone
alarm function according to the following signals:
Ignition switch (IG1): OFF
Ignition key reminder switch: ON
Front door switch (RH): ON
Taillamp switch: ON
Headlamp switch: ON
The ETACS-ECU operates the lamp reminder tone
alarm function under the following conditions:
Ignition switch: "LOCK" (OFF) position
Ignition key: Removed from the ignition key cylin-
der
Driver’s door: open
Taillamps or headlamps: ON
.
TECHNICAL DESCRIPTION (COMMENT)
If the function does not work normally, the input cir-
cuit system from the switches or the ETACS-ECU
may be defective (refer to "CIRCUIT OPERATION").
.
TROUBLESHOOTING HINTS
Trouble in input signal system
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The ETACS-ECU may be defective
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
DIAGNOSIS
Required Special Tools:
MB991223: Harness Set
MB991958: diagnostic tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.)
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
MB991813: SWS Monitor Kit
MB991806: SWS Monitor Cartridge
Page 101 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-101
Normal condition is not displayed for "FRONT DOOR
SW" : Refer to Inspection Procedure M-4 "ETACS-ECU
does not receive any signal from the front door
switches P.54B-413."
Normal condition is not displayed for "H/L AUTO-CUT" :
Refer to Inspection Procedure H-9 "Headlamp
automatic shutoff function does not work normally
P.54B-305."
Normal condition is not displayed for "BUZZER" :
Replace the ETACS-ECU. The lamp reminder tone
alarm function should now work normally.
INSPECTION PROCEDURE B-3: Tone Alarm: Seat Belt Tone Alarm Function does not Work Normally.
NOTE: This troubleshooting procedure requires the
use of diagnostic tool MB991958 and SWS monitor
kit MB991813. For details on how to use the SWS
monitor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
The ETACS-ECU receives the driver's seat belt
switch ON signal from the ignition switch (IG1) and
the combination meter, and then controls the seat
belt tone alarm function.
The ETACS-ECU operates the seat belt tone alarm
function under the following conditions:
Ignition switch: "ON" position
Driver's seat belt: Unfastened
.
TECHNICAL DESCRIPTION (COMMENT)
If the seat belt tone alarm does not work, connec-
tor(s), wiring harness in the CAN bus lines, the com-
bination meter, the ETACS-ECU or the input signal
circuit may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Trouble in input signal system
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The ETACS-ECU may be defective
Page 106 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-106
INSPECTION PROCEDURE B-4: Tone Alarm: Door ajar Warning Buzzer Function does not Work
Normally.
NOTE: This troubleshooting procedure requires the
use of diagnostic tool MB991958 and SWS monitor
kit MB991813. For details on how to use the SWS
monitor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
The ETACS-ECU controls the door-ajar warning tone
alarm, based on the signals from the switches and
sensors below.
Ignition switch (IG1): ON
One of the door switches: ON
Vehicle speed signal: 8 km/h (5 mph) or more
.
TECHNICAL DESCRIPTION (COMMENT)
If the door-ajar warning tone alarm does not work,
connector(s), wiring harness in the CAN bus lines,
the combination meter, the ETACS-ECU or the input
signal circuit may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Trouble in input signal system
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The combination meter may be defective
The ETACS-ECU may be defective
Page 112 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-112
INSPECTION PROCEDURE B-5: Tone Alarm: The Multi center Display does not Sound Normally When
it is Operated.
NOTE: This troubleshooting procedure requires the
use of diagnostic tool MB991958 and SWS monitor
kit MB991813. For details on how to use the SWS
monitor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
The ETACS-ECU sounds the buzzer when it
receives buzzer signal from the multi center display
(MID).
.
TECHNICAL DESCRIPTION (COMMENT)
If this function does not work normally, connector(s),
wiring harness in the CAN bus lines, the mid-
dle-grade multi center display unit or the
ETACS-ECU may be defective.
.
TROUBLESHOOTING HINTS
Trouble in input signal system
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The ETACS-ECU may be defective
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
DIAGNOSIS
Required Special Tools:
MB991223: Harness Set
MB991958: diagnostic tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.)
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
MB991813: SWS Monitor Kit
MB991806: SWS Monitor Cartridge
MB991812: SWS Monitor Harness (For Column-ECU)
MB991822: Test Probe Harness
STEP 1. Check the operation of the multi center display
(MID).
Q: Does the multi center display work normally?
YES : Go to Step 2.
NO : First, replace the multi center display unit.
Page 116 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-116
INSPECTION PROCEDURE B-6: Tone Alarm: Turn-signal Lamp Buzzer Function does not Work
Normally.
NOTE: This troubleshooting procedure requires use
of diagnostic tool MB991958 and SWS monitor kit
MB991813. For details on how to use the SWS mon-
itor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
The ETACS-ECU controls the turn-signal lamp
buzzer function, based on the switch signals below:
Turn-signal lamp switch: ON
Hazard switch: ON
.
TECHNICAL DESCRIPTION (COMMENT)
If the turn-signal lamp buzzer function does not work
normally, connector(s), wiring harness, the column
switch, the ETACS-ECU or the input signal circuit
may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Trouble in input signal system
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The ETACS-ECU may be defective
DIAGNOSIS
Required Special Tools:
MB991223: Harness Set
MB991958: diagnostic tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.)
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
MB991813: SWS Monitor Kit
MB991806: SWS Monitor Cartridge
MB991812: SWS Monitor Harness (For Column-ECU)
MB991822: Test Probe Harness
STEP 1. Check the adjustment function.
Q: Has the turn-signal lamp buzzer function been enabled
by the adjustment function?
YES : Go to Step 2.
NO : Enable the turn-signal lamp buzzer function.
Page 122 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-122
INSPECTION PROCEDURE C-1: Central Door Locking System: The Central Door Locking System
does not Work at all.
NOTE: This troubleshooting procedure requires the
use of diagnostic tool MB991958 and SWS monitor
kit MB991813. For details on how to use the SWS
monitor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
The ETACS-ECU controls the central door lock
system, locking or unlocking all the doors by acti-
vating the central door lock relay (built into the
ETACS-ECU). The ETACS-ECU uses inputs from
the following components:
Front door lock actuator
Front door lock key cylinder switch
Door lock switch, which is incorporated in the
power window main switch or front power win-
dow sub switch
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The ETACS-ECU may be defective