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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 306 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-306
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 adjustment function.
Q: Has a setting other than "No auto-shutoff" been
selected for the headlamp automatic shutdown
function?
YES : Go to Step 2.
NO : Set the headlamp automatic shutdown function to
another setting other than "No auto-shutoff".
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-307
STEP 2. Check the input signal by using "DATA LIST"
menu of the SWS monitor.
Check the input signals from the following switches:
Ignition switch: "ON" to "OFF"
Lighting switch: "TAIL" or "HEAD"
To prevent damage to Diagnostic Tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting Diagnostic Tool
MB991958. Connect special tool MB991910 before con-
necting special tool MB991812. Be sure to connect special
tool MB991806 after turning on special tool MB991824.
(1) Connect the special tool. Refer to "How to connect SWS
monitor P.54B-13."
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Operate Diagnostic Tool MB991958 according to the
procedure below to display "H/L AUTO-CUT."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "LIGHTING."
g. Select "H/L AUTO-CUT."
(4) Check that normal conditions are displayed for the items
described in the table below.
(5) When the driver's door is opened, 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", "IG SW IG1", "FRONT DOOR SW" and
"H/L AUTO-CUT" as normal condition?
Normal conditions are displayed for all the items :
Replace the front-ECU. Verify that the headlamp
automatic shutdown function works normally.
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 "IG SW (IG1)" :
Refer to Inspection Procedure M-2 "ETACS-ECU
does not receive any signal from the ignition switch ITEM NO. ITEM NAME NORMAL CONDITION
ITEM 01 TAILLAMP SW ON
ITEM 30 IG SW (IG1) OFF
ITEM NO. ITEM NAME NORMAL CONDITION
ITEM 32 FRONT DOOR SW ON
ITEM 35 H/L AUTO-CUT ON
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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
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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.
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-311
STEP 2. Check the turn-signal lamps.
Q: Does either of the turn-signal lamps illuminate?
Only right or left side lamp does not illuminate. : Go to
St e p 3 .
Turn-signal lamps do not illuminate at all : Go to Step 4.
STEP 3. Check ETACS-ECU connector C-219, junction
block connectors C-214 and C-204 for loose, corroded or
damaged terminals, or terminals pushed back in the
connector.
Q: Are ETACS-ECU connector C-219, junction block
connectors C-214 and C-204 in good condition?
YES : Replace the ETACS-ECU. Verify that the turn-signal
lamps illuminate normally.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Verify that the turn-signal lamps illuminate
normally.
STEP 4. Check ETACS-ECU connector C-219 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is ETACS-ECU connector C-219 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 turn-signal lamps illuminate
normally.
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-312
STEP 5. Check the battery power supply circuit to the
ETACS-ECU. Measure the voltage at ETACS-ECU
connector C-219.
(1) Disconnect ETACS-ECU connector C-219, and measure
the voltage available at the junction block side of the
connector.
(2) Measure the voltage between terminal 11 and ground.
The voltage should measure approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approximately 12 volts (battery
positive voltage)?
YES : Replace the ETACS-ECU. Verify that the turn-signal
lamps illuminate normally.
NO : Go to Step 6.
STEP 6. Check the wiring harness between ETACS-ECU
connector C-219 (terminal 11) and the battery.
NOTE: Also check junction block connector C-214 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-214 is damaged,
Repair or replace the damaged component(s) as described in
GROUP 00E, Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between ETACS-ECU connector
C-219 (terminal 11) 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 turn-signal lamps illuminate normally.