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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
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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
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-99
MB991812: SWS Monitor Harness (For Column-ECU)
MB991822: Test Probe Harness
STEP 1. Use diagnostic tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the following ECUs:
ETACS-ECU
Column switch (column-ECU)
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958. Connect special tool MB991910 before con-
necting special tool MB991812. Be sure to connect special
tool MB991806 after turning on special tool MB991824.
(1) Connect the special tool. Refer to "How to connect SWS
monitor P.54B-13."
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Operate diagnostic tool MB991958 according to the
procedure below to display "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System Select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check."
(4) diagnostic tool MB991958 should show "OK" on the "ECU
COMM Check" menus for both the "ETACS ECU" and the
"COLUMN ECU" menus.
Q: Is "OK" displayed for both the "ETACS ECU" and
"COLUMN ECU" menus?
"OK" is displayed for all the items : Go to Step 2.
"NG" is displayed for the "ETACS ECU" menu : Refer to
Inspection Procedure A-3 "Communication with the
ETACS-ECU is not possible P.54B-74."
"NG" is displayed for the "COLUMN ECU" menu : Refer
to Inspection Procedure A-2 "Communication with the
column switch (column-ECU) is not possible
P.54B-68."
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-100
STEP 2. Check the input signal by using "FUNCTION
DIAG." menu of the SWS monitor.
Check the input signals from the following switches:
Ignition switch: OFF (key removed)
Lighting switch: TAIL or HEAD
Driver’s door: open
Front passenger's door: closed
(1) Operate diagnostic tool MB991958 according to the
procedure below to display "LGT MONI. ALRM."
a. Select "Interactive Diagnosis."
b. Select "System Select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "BUZZER."
g. Select "LGT MONI. ALRM."
(2) Check that normal conditions are displayed for the items
described in the table below.
NOTE: diagnostic tool MB991958 display changes when
the driver's or the front passenger's door is opened. If any of
the doors is open, the system cannot be checked correctly.
Q: Does diagnostic tool MB991958 display "HEADLAMP
SW", "TAILLAMP SW", "IG SW IG1", "FRONT DOOR
SW", "H/L AUTO-CUT" and "BUZZER" as normal
condition?
Normal conditions are displayed for all the items :
Replace the ETACS-ECU. The lamp reminder tone
alarm function should now work normally.
Normal condition is not displayed for "HEADLIGHT SW"
: Refer to Inspection Procedure M-5 "ETACS-ECU
does not receive any signal from the headlamp switch
P.54B-420."
Normal condition is not displayed for "TAILLIGHT SW" :
Refer to Inspection Procedure M-5 "ETACS-ECU
does not receive any signal from the taillamp switch
P.54B-420."
Normal condition is not displayed for "IG SW (IG1)" :
Refer to Inspection Procedure M-2 "ETACS-ECU
does not receive any signal from the ignition switch
(IG1) P.54B-408." ITEM NO. ITEM NAME NORMAL CONDITION
ITEM 00 HEADLAMP SW Either of items is ON
ITEM 01 TAILLAMP SW
ITEM 30 IG SW IG1 OFF
ITEM 32 FRONT DOOR SW ON
ITEM 35 H/L AUTO-CUT OFF
ITEM 43 BUZZER ON
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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
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-102
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. Using diagnostic tool MB991958, diagnose the
CAN bus line.
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
(1) Connect diagnostic tool MB991958. Refer to "How to
connect SWS monitor P.54B-13."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?
YES : Go to Step 2.
NO : Repair the CAN bus line (Refer to GROUP 54C,
Diagnosis P.54C-5).
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-103
STEP 2. Using diagnostic tool MB991958, read the
combination meter diagnostic trouble code.
Check whether the combination meter-related DTC is set.
(1) Turn the ignition switch to the "ON" position.
(2) Check whether the combination meter-related DTC is set.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES : Diagnose the multi center display unit (Refer to
GROUP 54A, Diagnosis P.54A-254).
NO : Go to Step 3.
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-104
STEP 3. Use diagnostic tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the ETACS-ECU.
Connect special tool MB991910 before connecting special
tool MB991812. Be sure to connect special tool MB991806
after turning on special tool MB991824.
(1) Connect the SWS monitor. Refer to "How to connect SWS
monitor P.54B-13."
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Operate diagnostic tool MB991958 according to the
procedure below to display "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System Select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check."
(4) diagnostic tool MB991958 should show "OK" on the "ECU
COMM Check" menu for the "ETACS ECU" menu.
Q: Is "OK" displayed for the "ETACS ECU" menu?
YES : Go to Step 4.
NO : Refer to Inspection Procedure A-3 "Communication
with the ETACS-ECU is not possible P.54B-74."