Page 194 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-194
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
STEP 1. Verify the keyless entry system.
Q: Does the keyless entry system work normally?
YES : Go to Step 2.
NO : Refer to Inspection Procedure E-1 "Keyless entry
system does not operate P.54B-191."
STEP 2. Check the configuration function.
Q: Has the answerback function been enabled by means of
the adjustment function?
YES : Go to Step 3.
NO : Enable the answerback function by means of the
adjustment function. Verify that the answerback
functions work normally.
STEP 3. Verify trouble symptom.
Q: Which answerback function is defective?
Only the dome lamp : Go to Step 4.
Only the turn-signal lamps : Go to Step 5.
Only the horn : Go to Step 6.
Dome lamp, turn-signal lamps and horn : Replace the
ETACS-ECU. Verify that the answerback functions
work normally.
STEP 4. Verify the dome lamp.
Q: Does the dome lamp illuminate normally?
YES : Replace the ETACS-ECU. Verify that the answerback
functions work normally.
NO : Refer to Inspection Procedure K-1 "The dome lamp
do not illuminate and go out normally P.54B-359."
STEP 5. Verify the hazard warning lamp.
Q: Does the hazard warning lamp work normally?
YES : Replace the ETACS-ECU. Verify that the answerback
functions work normally.
NO : Refer to Inspection Procedure I-2 "Hazard warning
lamps do not flash when the hazard warning lamp
switch is turned on P.54B-314."
Page 202 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-202
INSPECTION PROCEDURE E-3: Keyless Entry System: Encrypted code cannot be registered.
.
CIRCUIT OPERATION
The ETACS-ECU operates the encrypted code regis-
ter mode according to the following signals:
Key reminder switch
Hazard warning lamp switch
.
TECHNICAL DESCRIPTION (COMMENT)
If the encrypted code register mode cannot be set,
the input circuits from the switches described in
"CIRCUIT OPERATION" or the ETACS-ECU may be
defective.
If the encrypted code register mode can be set but
the transmitter cannot be registered, the transmitter
or the ETACS-ECU may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The key reminder switch may be defective
The hazard warning lamp switch may be defec-
tive
The transmitter may be defective
The ETACS-ECU may be defective
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
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
STEP 1. Verify trouble symptom.
Q: Can the encrypted code register mode be set?
YES : Go to Step 3.
NO : Go to Step 2.
Page 205 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-205
INSPECTION PROCEDURE E-4: Keyless Entry System: The trunk is not opened when the keyless
entry transmitter "TRUNK" button is operated.
.
CIRCUIT OPERATION
A receiver is incorporated in the ETACS-ECU. This
receiver receives a lock or unlock signal from the
transmitter.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The RKE transmitter may be defective
The ETACS-ECU may be defective
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
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
STEP 1. Check that the doors can be locked and unlocked
by using the keyless entry transmitter.
Q: Can the doors be locked and unlocked normally when
the keyless entry transmitter is operated?
YES : Go to Step 2.
NO : Refer to Inspection Procedure E-1 "Keyless entry
system does not operate P.54B-191."
Page 219 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-219
INSPECTION PROCEDURE F-2: Sunroof: Any of the sunroof switch positions is defective.
.
TECHNICAL DESCRIPTION (COMMENT)
The sunroof switch or the sunroof motor assembly
may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The sunroof switch may be defective
The sunroof motor assembly may be defective
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
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
Check the input signal (by using the pulse check mode of
the monitor).
Check the input signals from the sunroof switch.
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) Operate the diagnostic tool MB991958 according to the
procedure below to display "Pulse check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "Pulse Checking."
(3) When each function of the sunroof switch is operated
(turned on), check that diagnostic tool MB991958 sounds.
Q: Does diagnostic tool MB991958 sound when the
sunroof switch is operated?
YES : Replace the sunroof motor assembly. Check that the
sunroof works at all positions normally.
NO : Refer to Inspection Procedure M-8 "ETACS-ECU
does not receive any signal from the up, open or
close/down switch P.54B-429."
Page 220 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-220
INSPECTION PROCEDURE F-3: Sunroof: Sunroof Timer Function does not Work Normally.
NOTE: This troubleshooting requires use of
diagnostic tool MB991958 and SWS monitor kit
MB991813. For details of how to use the SWS moni-
tor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
The sunroof timer function works according to the
signals from the following switches:
Ignition switch (IG1): OFF
Front door switch: OFF
Vehicle condition
Ignition switch: LOCK position
Front door: Closed
When the driver’s door is opened and closed
while the sunroof timer function is on, the sunroof
operative duration will be changed.
.
TECHNICAL DESCRIPTION (COMMENT)
Is the sunroof timer function does not work normally,
the input circuits from the switches described in
"CIRCUIT OPERATION", the sunroof motor assem-
bly, the ETACS-ECU or the SWS communication line
may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The front door switch may be defective
The sunroof motor assembly may be defective
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
DIAGNOSIS
Required Special Tools:
MB991223: Test 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
Page 227 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-227
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
Page 234 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-234
INSPECTION PROCEDURE G-2: Windshield Wiper and Washer: The windshield wipers do not work
when the windshield wiper switch is at "INT" or "MIST" position or the windshield washer switch is at
"ON" position. However, the wipers work at low speed when the windshield wiper switch is at "LO" or
"HI."
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."
.
TECHNICAL DESCRIPTION (COMMENT)
This system may be at fail-safe mode as the SWS
communication line is defective.
If the system cannot receive any signal from the col-
umn switch (windshield wiper and washer switch)
due to a open circuit in the SWS communication line
or other reasons, the system will enter the fail-safe
mode when the ignition switch is at the "ACC" posi-
tion.
.
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 column switch may be defective
The front-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
Page 236 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-236
INSPECTION PROCEDURE G-3: Windshield Wiper and Washer: All of the windshield wiper switch
positions are defective.
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."
.
TECHNICAL DESCRIPTION (COMMENT)
If either of the windshield wiper switch positions is
defective, the windshield wiper motor, column switch
(windshield wiper and washer switch) or the
front-ECU 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 wiper motor may be defective
The front-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