Page 275 of 1500
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
.
Page 290 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-290
INSPECTION PROCEDURE H-7: Headlamp and Taillamp: One of the headlamps does not illuminate.
.
TECHNICAL DESCRIPTION (COMMENT)
If one of the headlamps does not illuminate, a
headlamp bulb may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The headlamp bulb may be defective
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
.
Page 301 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-301
STEP 25. Check the wiring harness between headlamp
(RH) connector A-32 (terminals 5 and 1) and ground.
Q: Is the wiring harness between headlamp (RH) connector
A-32 (terminals 5 and 1) and ground 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 illuminate normally.
INSPECTION PROCEDURE H-8: Headlamp and Taillamp: The High-beam indicator lamp does 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."
.
CIRCUIT OPERATION
At the same time that the high beams are illumi-
nated, the ETACS-ECU sends a signal to illuminate
the high beam indicator via the CAN bus line.
.
TECHNICAL DESCRIPTION (COMMENT)
If the high beam indicator does not illuminate nor-
mally, connector(s), wiring harness in the CAN bus
lines, the ETACS-ECU or the combination meter 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
.
Page 305 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-305
INSPECTION PROCEDURE H-9: Headlamp and Taillamp: Headlamp automatic shutoff 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 headlamp automatic
shutdown function according to the following signals:
Ignition switch (IG1): OFF
Driver's door switch: ON
Taillamp switch: ON
Headlamp switch: ON
The ETACS-ECU operates the headlamp automatic
shutdown function under the following conditions:
Ignition key: Other than "ON" position
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, the ETACS-ECU or
the front-ECU may be defective (refer to "CIRCUIT
OPERATION").
.
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
Page 308 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-308
(IG1) P.54B-408."
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" :
Replace the front-ECU. Check that the headlamp
automatic shutdown function works normally.
INSPECTION PROCEDURE H-10: Headlamp and Taillamp: Headlamp dimmer switch automatic
resetting function does not work normally.
.
CIRCUIT OPERATION
The headlamp dimmer switch automatic resetting
function is controlled by the front-ECU.
.
TECHNICAL DESCRIPTION (COMMENT)
If the headlamp dimmer switch automatic resetting
function does not work normally, the front-ECU may
be defective.
.
TROUBLESHOOTING HINT
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The front-ECU may be defective
DIAGNOSIS
Replace the front-ECU.
Check that the headlamp dimmer switch automatic resetting
function works normally.
Page 309 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-309
FLASHER TIMER
GENERAL DESCRIPTION CONCERNING THE FLASHER TIMERM1549023600238
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80The following ECUs affect the functions and control
of the flasher timer.
FLASHER TIMER FUNCTION
.
TURN-SIGNAL LAMP
The turn-signal lamp output (flashing signal) is turned ON when
the ignition switch is ON and the turn-signal lamp switch is ON
(LH or RH). If the front turn-signal lamp or rear turn-signal lamp
bulb has burned out, the flashing speed increases to indicate
that the bulb has burned out.
NOTE: If LH or RH side turn signal lamp bulbs have burned
out, the flashing speed will remain the same.
.
TURN-SIGNAL INDICATORS
At the same time that the turn-signal lamps are illuminated, the
ETACS-ECU sends a signal to illuminate the turn-signal lamp
indicator via the CAN bus line. The combination meter receives
the transmitted signal and turns the turn-signal lamp indicator
on and off.
.
HAZARD WARNING LAMP
Detects the signal where the hazard warning lamp switch input
changes from OFF to ON, and reverse the flashing state
according to this signal. The hazard warning lamps toggle on
and off whenever the hazard warning lamp switch is operated.
NOTE: The hazard warning lamp switch is a push-return type
toggle switch. FUNCTION CONTROL ECU
Turn-signal lamp ETACS-ECU, column switch
Turn-signal indicators ETACS-ECU, column switch
Hazard warning lamp ETACS-ECU
Page 310 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-310
INSPECTION PROCEDURE I-1: Flasher Timer: Turn-signal lamps do not flash when the turn-signal
lamp switch is turned on.
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 turn-signal lamp switch sends a signal
through the column-ECU (incorporated in the col-
umn switch) to the ETACS-ECU. If the col-
umn-ECU sends a turn-signal lamp switch "ON"
signal to the ETACS-ECU, the ETACS-ECU turns
on the flasher timer (incorporated in the
ETACS-ECU), thus causing the turn-signal lamps
to flash.
The ETACS-ECU operates the turn-signal lamps
according to the following signals:
Ignition switch (IG1): ON
Turn-signal lamp switch: ON
The ETACS-ECU flashes the turn-signal lamps
under the following conditions:
Ignition key: "ON" position
Turn-signal lamp switch: Left or right turn-sig-
nal position
.
TECHNICAL DESCRIPTION (COMMENT)
If the turn-signal lamps do not flash normally, the
input circuits from the switches described in "CIR-
CUIT OPERATION" or the ETACS-ECU may be
defective. If the hazard warning lamps do not flash,
the power supply line to the ETACS-ECU (dedicated
to the turn-signal lamps) 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
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 hazard warning lamp.
Q: Do the hazard warning lamps work normally?
YES : Go to Step 7.
NO : Go to Step 2.
Page 314 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-314
STEP 8. Check the input signal by using "FUNCTION
DIAG." menu of the SWS monitor.
If the Ignition switch is turned to the "ON" position and the
turn-signal lamp switch (LH) is turned on, normal conditions
should be displayed for the items described in the table below.
(1) Operate Diagnostic Tool MB991958 according to the
procedure below to display "TURN SIG.LH."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "TURN SIGNAL."
g. Select "TURN SIG.LH."
(2) Check that normal conditions are displayed for the item
described in the table below.
Q: Do the Diagnostic Tool display the item "T/S LH SW" as
normal condition?
YES : Replace the ETACS-ECU. Verify that the turn-signal
lamps illuminate normally.
NO : Refer to Inspection Procedure M-5 "ETACS-ECU
does not receive any signal from the turn-signal lamp
switch P.54B-420."
INSPECTION PROCEDURE I-2: Flasher Timer: Hazard warning lamps do not flash when the hazard
warning lamp switch is turned on.
.
CIRCUIT OPERATION
If the ETACS-ECU receives "ON" signal from the
hazard warning lamp switch, the ETACS-ECU turns
on the flasher timer (incorporated in the
ETACS-ECU), thus causing the turn-signal lamps to
flash.
.
TECHNICAL DESCRIPTION (COMMENT)
If the hazard warning lamps do not flash, the power
supply line to the ETACS-ECU (dedicated to the
turn-signal lamps) or the ETACS-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 ETACS-ECU may be defective ITEM No. ITEM NAME NORMAL CONDITION
ITEM 11 T/S LH SW ON