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-257
HEADLAMP AND TAILLAMP
GENERAL DESCRIPTION CONCERNING THE HEADLAMPS AND TAILLAMPSM1549021300264
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80The following ECUs affect the functions and control
of the headlamps and the taillamps.
FUNCTION CONTROL ECU
Taillamps Front-ECU, column switch
Headlamps ETACS-ECU, front-ECU, column switch
High-beam indicator lamp ETACS-ECU, column switch
Headlamp automatic-shutoff function ETACS-ECU, front-ECU, column switch
Dimmer automatic reset function Front-ECU, column switch
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
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-264
STEP 5. Check the wiring harness between front-ECU
connector A-11X (terminal 7) and the battery.
Q: Is the wiring harness between front-ECU connector
A-11X (terminal 7) and the battery in good condition?
YES : No action is necessary and testing is complete.
NO : The wiring harness may be damaged or the
connector(s) may have loose, corroded or damaged
terminals, or terminals pushed back in the connector.
Repair the wiring harness as necessary. Verify that
the taillamps illuminate normally.
INSPECTION PROCEDURE H-2: Headlamp and Taillamp: The headlamps (low-beam) 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 use the SWS
monitor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
When the lighting switch is set to "HEAD" posi-
tion, the "HEAD" signal is sent through the col-
umn-ECU (incorporated in the column switch) to
the front-ECU. If the front-ECU receives the
"HEAD" signal through the column-ECU, the
front-ECU turns on the headlamp relay (incorpo-
rated in the front-ECU), thus causing the
headlamps to illuminate. The headlamps always
illuminate at low-beam by the headlamp dimmer
switch automatic resetting function.
If the SWS communication line is defective, the
front-ECU operates the headlamps by using the
other communication lines (headlamp backup cir-
cuit) instead of that line.
.
TECHNICAL DESCRIPTION (COMMENT)
If the headlamps (low-beam) do not illuminate nor-
mally, 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
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-268
STEP 5. Check the wiring harness between front-ECU
connector A-11X (terminals 8 and 9) and the battery.
Q: Is the wiring harness between front-ECU connector
A-11X (terminals 8 and 9) and the battery in good
condition?
YES : No action is necessary and testing is complete.
NO : The wiring harness may be damaged or the
connector(s) may have loose, corroded or damaged
terminals, or terminals pushed back in the connector.
Repair the wiring harness as necessary. Verify that
the headlamps (low-beam) illuminate normally.
INSPECTION PROCEDURE H-3: Headlamp and Taillamp: The headlamps (high-beam) 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 use the SWS
monitor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
When the dimmer switch is turned on, the column
switch sends a signal to the front-ECU. Then the
front-ECU switches the headlamps from low-beam to
high beam or vice versa.
.
TECHNICAL DESCRIPTION (COMMENT)
If the headlamps (high beam) do not illuminate nor-
mally, 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
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-271
INSPECTION PROCEDURE H-4: Headlamp and Taillamp: When the passing switch is turned "ON," the
headlamps (low-beam or high-beam) do not illuminate.
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 both of the headlamps (low-beam and high-beam)
do not illuminate, the input circuit from the passing
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
STEP 1. Check the headlamps.
Q: Do the headlamps (low-beam and high-beam) illuminate
normally?
The headlamps illuminate normally. : Go to Step 2.
Headlamps (low-beam) do not illuminate normally :
Refer to Inspection Procedure H-2 "The headlamps
(low-beam) do not illuminate normally P.54B-264.
Headlamps (high-beam) do not illuminate normally :
Refer to Inspection Procedure H-3 "The headlamps
(high-beam) do not illuminate normally P.54B-268.
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-273
INSPECTION PROCEDURE H-5: Headlamp and Taillamp: Headlamps do not illuminate when the
lighting switch is at "TAIL," and "PASSING" position, but illuminate at low-beam when the switch is at
"HEAD" position. At this position, the headlamps cannot be changed to high beam by operating the
dimmer 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 headlamps illuminate at low-beam regardless
of the lighting switch positions, the headlamp opera-
tion is in fail-safe mode.
.
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 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-275
INSPECTION PROCEDURE H-6: Headlamp and Taillamp: The front park lamps, taillamps or the
licence plate lamps do not illuminate.
.
TECHNICAL DESCRIPTION (COMMENT)
If the front park lamps, taillamps or the licence plate
lamp do not illuminate, their bulb may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The front park lamp bulb may be defective
The stop/taillamp bulb may be defective
The licence plate lamp bulb may be defective
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
.