turn signal MITSUBISHI 380 2005 Repair Manual
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 268 of 1500
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 
Page 270 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-270
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
Dimmer switch: ON
(1) Operate Diagnostic Tool MB991958 according to the 
procedure below to display "HEADLAMP HI."
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 HI."
(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", "DIMMER SW", "H/L AUTO-CUT" and 
"FRONT ECU ACK" as normal condition?
Normal conditions are displayed for all the items : 
Replace the front-ECU. Verify that the headlamps 
(high-beam) illuminate normally.
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 "DIMMER SW" : 
Refer to Inspection Procedure M-5 "ETACS-ECU 
does not receive any signal from the dimmer 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 
(high-beam) illuminate normally. ITEM NO. ITEM NAME NORMAL CONDITION
ITEM 00 HEADLAMP SW ON
ITEM 02 DIMMER SW OFF (should turn "ON" 
momentarily when the 
dimmer switch is operated)
ITEM 35 H/L AUTO-CUT OFF
ITEM 70 FRONT ECU ACK HI-BEAM ACK 
Page 271 of 1500
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. 
Page 272 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-272
STEP 2. Check the input signal by using "DATA LIST" 
menu of the SWS monitor.
Turn the passing switch to the "ON" position before checking 
input signals from the passing switch.
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) Operate Diagnostic Tool MB991958 according to the 
procedure below to display "COLUMN ECU."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Data List."
f. Select "COLUMN ECU."
(3) Check that normal conditions are displayed for the items 
described in the table below.
Q: Does the Diagnostic Tool MB991958 display "PASSING 
SW" as normal condition?
YES : Replace the front-ECU. When the passing switch is 
turned "ON", the headlamps (low-beam and 
high-beam) should illuminate normally.
NO : Refer to Inspection Procedure M-5 "ETACS-ECU 
does not receive any signal from the passing switch 
P.54B-420." ITEM NO. ITEM NAME NORMAL CONDITION
ITEM 03 PASSING SW ON 
Page 307 of 1500
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 
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.