SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-226
INSPECTION PROCEDURE G-1: Windshield Wiper and Washer: The windshield wiper do not work at
all.
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 windshield wiper and washer switch sends a
signal through the column-ECU (incorporated in
the column switch) to the front-ECU. If the col-
umn-ECU sends a windshield wiper and washer
switch "ON" signal to the front-ECU, the
front-ECU turns on the relay (incorporated in the
front-ECU), thus causing the windshield wiper
and washer motor to be turned on.
If the SWS communication line is defective, the
front-ECU operates windshield wiper motor by
using the other communication lines (wiper
backup circuit) instead of that line. In this case,
the windshield wiper works at low speed regard-
less of the windshield wiper and washer switch
positions ("LO" or "HIGH").
.
TECHNICAL DESCRIPTION (COMMENT)
If the windshield wiper does not work at all, the wind-
shield wiper motor, column switch (windshield wiper
and washer switch) or the front-ECU may be defec-
tive.
.
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 column switch may be defective
The front-ECU may be defective
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
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
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-246
INSPECTION PROCEDURE G-5: Windshield Wiper and Washer: The windshield intermittent wiper
interval cannot be adjusted by using the variable intermittent wiper control switch.
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."
.
TECHNICAL DESCRIPTION (COMMENT)
If the windshield intermittent wiper interval is not
changed by operating the windshield intermittent
wiper interval adjusting knob or according to the
vehicle speed, the column switch, the ETACS-ECU
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 ETACS-ECU 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
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-248
INSPECTION PROCEDURE G-6: Windshield Wiper and Washer: The windshield intermittent wiper
interval is not changed according to the vehicle speed.
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 the windshield intermittent wiper interval does not
change according to the vehicle speed, the
ETACS-ECU or the front-ECU may be defective.
.
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 combination meter may be defective
The ETACS-ECU 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
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-251
INSPECTION PROCEDURE G-7: Windshield Wiper and Washer: The windshield washer does not
work.
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 windshield washer switch sends a signal
through the column-ECU (incorporated in the column
switch) to the front-ECU. If the column-ECU sends a
windshield washer switch "ON" signal to the
front-ECU, the front-ECU turns on the relay (incorpo-
rated in the front-ECU), thus causing the windshield
washer motor to be turned on.
.
TECHNICAL DESCRIPTION (COMMENT)
If the windshield washer does not work normally, the
windshield washer motor, the column switch (wind-
shield 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
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The windshield washer motor may be defective
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
STEP 1. Verify the windshield wiper operation.
Q: Does the windshield wiper operate normally?
YES : Go to Step 2.
NO : Refer to Inspection Procedure G-1 "The windshield
wiper do not work at all P.54B-226."
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-253
STEP 3. Check the input signal by using "FUNCTION
DIAG." menu of the SWS monitor.
Check the input signals from the following switches:
Ignition switch: ACC
Windshield washer switch: ON
(1) Operate the Diagnostic Tool MB991958 according to the
procedure below to display "F.WIPER WASH."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "WIPER."
g. Select "F.WIPER WASH."
(2) Check that normal conditions are displayed for the items
described in the table below.
Q: Are normal conditions displayed for "FRONT
WASH.SW" and "FRONT ECU ACK"?
Normal conditions displayed for all the items : Go to
St e p 4 .
Normal condition is not displayed for the "FRONT
WASH.SW" : Replace the column switch. Verify that the
windshield washer works normally.
Normal condition is not displayed for the "FRONT ECU
ACK" : Replace the front-ECU. Verify that the windshield
washer works normally.
STEP 4. Check windshield washer motor connector A-29
for loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Is windshield washer motor connector A-29 in good
condition?
YES : Go to Step 5.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Verify that the windshield washer works
normally. ITEM NO. ITEM NAME NORMAL
CONDITION
ITEM 09 FRONT WASH.SW ON
ITEM 70 FRONT ECU ACK NORMAL ACK or
HI-BEAM ACK
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-260
INSPECTION PROCEDURE H-1: Headlamp and Taillamp: The taillamps do not illuminate normally.
NOTE: This troubleshooting procedure requires the
use of Diagnostic Tool MB991958 and SWS monitor
kit MB991813. For details on how to connect the
SWS monitor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
When the lighting switch is set to "TAIL" position, the
"TAIL" signal is sent through the column-ECU (incor-
porated in the column switch) to the front-ECU. If the
front-ECU receives the "TAIL" signal through the col-
umn-ECU, the front-ECU turns on the taillamp relay
(incorporated in the front-ECU), thus causing the
taillamps to illuminate.
.
TECHNICAL DESCRIPTION (COMMENT)
If the taillamps do not illuminate normally, the column
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 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