diagnostic MITSUBISHI 380 2005 Workshop Manual

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

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-265
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. Use Diagnostic Tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the following ECUs:
Column switch (column-ECU)
Front-ECU
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 "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check."
(4) Diagnostic Tool MB991958 should show "OK" on the "ECU
COMM Check" menus for both the "COLUMN ECU" and
the "FRONT ECU" menus.
Q: Is "OK" displayed for both the "COLUMN ECU" and
"FRONT ECU" menus?
"OK" is displayed for all the items : Go to Step 2.
"NG" is displayed for the "COLUMN ECU" menu : Refer
to Inspection Procedure A-2 "Communication with the
column switch (column-ECU) is not possible
P.54B-68."
"NG" is displayed for the "FRONT ECU" menu : Refer to
Inspection Procedure A-4 "Communication with the
front-ECU is not possible P.54B-80."

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

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-269
STEP 1. Use Diagnostic Tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the following ECUs:
Column switch (column-ECU)
Front-ECU
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 "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check."
(4) Diagnostic Tool MB991958 should show "OK" on the "ECU
COMM Check" menus for both the "COLUMN ECU" and
the "FRONT ECU" menus.
Q: Is "OK" displayed for both the "COLUMN ECU" and
"FRONT ECU" menus?
"OK" is displayed for all the items : Go to Step 2.
"NG" is displayed for the "COLUMN ECU" menu : Refer
to Inspection Procedure A-2 "Communication with the
column switch (column-ECU) is not possible
P.54B-68."
"NG" is displayed for the "FRONT ECU" menu : Refer to
Inspection Procedure A-4 "Communication with the
front-ECU is not possible P.54B-80."

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

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-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

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