Page 207 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-207
STEP 3. Check trunk lid latch assembly connector F-05
and ETACS-ECU connector C-217 for loose, corroded or
damaged terminals, or terminals pushed back in the
connector.
Q: Is trunk lid latch assembly connector F-05 and
ETACS-ECU connector C-217 in good condition?
YES : Go to Step 4.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Check that the headlamps illuminate
normally.
STEP 4. Check the trunk lid latch assembly.
Remove the trunk lid latch assembly. Refer to GROUP 42,
Trunk lid, Trunk lid latch inspection P.42-65.
Q: Does the windshield washer motor operate normally?
YES : Go to Step 5.
NO : Replace the trunk lid latch assembly. Verify that the
windshield washer works normally.
LEVER POSITION TESTER
CONNECTIONSPECIFIED
CONDITION
ON (Latch open) 2
Ground Less than 2 ohms
OFF (Latch shut) 2
Ground Open circuit
Page 257 of 1500
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
Page 258 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-258
Taillamps and headlamps illumination
.
Taillamps
If the column switch sends a taillamp switch "ON" signal to the
front-ECU, the front-ECU turns on its taillamp relay, causing the
taillamps to illuminate.
NOTE: This description covers the taillamps only. In actual driv-
ing, the taillamps may be turned off due to the headlamp auto-
matic shut-off function. For the details of the headlamp
automatic shut-off function, refer to .
.
Headlamps
If the column switch sends a headlamp switch "ON"
signal to the front-ECU, the front-ECU turns on its
headlamp relay (LOW), causing the low-beam
headlamps to illuminate. If the dimmer switch is
turned on while the headlamp relay (LOW) is on, the
front-ECU turns on the headlamp relay (HIGH),
causing the high-beam headlamps to illuminate.NOTE: This description covers the headlamps only.
In actual driving, the headlamps may be turned off
due to the headlamp automatic shut-off function. For
the details of the headlamp automatic shut-off func-
tion, refer to .
High-beam indicator lamp
At the same time that the high-beams are illuminated, the
ETACS-ECU sends a signal to illuminate the high beam indica-
tor via the CAN bus line. The combination meter receives the
transmitted signal and turns the high-beam indicator on and off.
Page 259 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-259
Headlamp automatic-shutdown function
Even if the lighting switch (taillamps switch or headlamp switch)
is ON, the headlamps (including the taillamps) will automati-
cally go off in the following conditions to prevent the battery
from discharging as a result of forgetting to turn off lamps.
If the ignition key is turned from "ON" to "LOCK" (OFF) or
"ACC" position with the lighting switch turned ON, and this
state continues for three minutes, the headlamps will automati-
cally be turned off. If the driver's seat door is opened during
these three minutes, the headlamps will go off one second
later.
NOTE: The headlamp automatic-shutoff function can be cus-
tomized on vehicles equipped with a multi center display (mid-
dle grade type). Refer to P.54B-486.
Dimmer automatic reset function
If the headlamp switch is turned off while the high-beam
headlamps are on, the dimmer switch will be reset. Because of
this, the headlamps will illuminate at low beam the next time
that they are turned on. The dimmer switch will be also reset if
the dimmer switch is turned on unintentionally while the pass-
ing switch is operated.
Page 260 of 1500

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
Page 262 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-262
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: ON
Lighting switch: TAIL
NOTE: Turn the ignition switch to the "ON" position in order to
disable the headlamp automatic shutdown function.
(1) Operate Diagnostic Tool MB991958 according to the
procedure below to display "TAILLAMP."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "LIGHTING."
g. Select "TAILLAMP."
(2) Check that normal conditions are displayed for the items
described in the table below.
Q: Does the Diagnostic Tool MB991958 display the items
"TAILLAMP SW", "H/L AUTO-CUT" and "FRONT ECU
ACK" as normal condition?
Normal conditions are displayed for all the items : Go to
St e p 3 .
Normal condition is not displayed for "TAILLAMP 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 "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 "FRONT ECU
ACK" : Replace the front-ECU. Verify that the taillamps
illuminate normally. ITEM NO. ITEM NAME NORMAL CONDITION
ITEM 01 TAILLAMP SW ON
ITEM 35 H/L AUTO-CUT OFF
ITEM 70 FRONT ECU ACK NORMAL ACK
Page 264 of 1500

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
Page 266 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-266
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: ON
Lighting switch: HEAD
(1) Operate Diagnostic Tool MB991958 according to the
procedure below to display "HEADLAMP LO."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "LIGHTING."
g. Select "HEADLAMP LO."
(2) Check that normal conditions are displayed for the items
described in the table below.
Q: Does the Diagnostic Tool MB991958 display the items
"HEADLAMP SW", "H/L AUTO-CUT" and "FRONT ECU
ACK" as normal condition?
Normal conditions are displayed for all the items : Go to
St e p 3 .
Normal condition is not displayed for "HEADLAMP 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 "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 "FRONT ECU
ACK" : Replace the front-ECU. Verify that the headlamps
(low-beam) illuminate normally. ITEM NO. ITEM NAME NORMAL
CONDITION
ITEM 00 HEADLAMP SW ON
ITEM 35 H/L AUTO-CUT OFF
ITEM 70 FRONT ECU ACK NORMAL ACK