Mitsubishi Galant (2004+). Manual - part 205

SWS DIAGNOSIS

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-11

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
NOTE: If the battery voltage is low, diagnostic trouble codes will 
not be set. Check the battery if scan tool MB991958 does not 
display.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System select."
5. Choose "ETACS" from the "BODY" tab.
6. Select "Diagnostic Trouble Code."
7. If a DTC is set, it is shown.
8. Choose "Erase DTCs" to erase the DTC.

HOW TO DIAGNOSE THE CAN BUS LINES

Required Special Tools:

•  MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "CAN bus diagnosis" from the start-up screen.
4. When the vehicle information is displayed, confirm that it 

matches the vehicle being diagnosed.

• If they match, go to step 8.

• If not, go to step 5.

5. Select the "view vehicle information" button.
6. Enter the vehicle information and select the "OK" button.
7. When the vehicle information is displayed, confirm again 

that it matches the vehicle being diagnosed.

• If they match, go to step 8.

• If not, go to step 5.

8. Select the "OK" button.
9. When the optional equipment screen is displayed, choose 

the one which the vehicle is fitted with, and then select the 
"OK" button.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

SWS DIAGNOSIS

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-12

SWS DIAGNOSTIC TROUBLESHOOTING STRATEGY

M1549000500575

1. Gather information about the problem from the 

customer.

2. Verify that the condition described by the 

customer exists.
NOTE:  If an error occurs in the SWS communica-
tion line, the ECU isolated from the communica-
tion line performs a fail-safe or backup operation, 
so the problem may not match the one shown in 
the Trouble Symptom Chart. However, the cause 
of the failure can be tracked down by performing 
the following troubleshooting with the SWS moni-
tor.

3. Version number and destination check

Check whether the SWS version number (1) and 
destination (North America) meet the vehicle 
specifications. If they are different, replace the 
ETACS-ECU with a correct one.

4. Use scan tool MB991958 (MUT-III Sub Assembly) 

to select "ECU COMM Check" on the SWS 
monitor display.
Check whether the communication status of the 
input- or output-signal-side ECU associated with 
the defective function is normal.

• If "OK" is displayed for all related ECUs, they 

communicate with each other normally and the 
input or output signal circuit system may be 
defective. Therefore, check SWS monitor service 
data.

• If "NG" is displayed for any of the related ECUs, 

something may be wrong with the ECU for which 
"NG" appears, its power supply or grounding sys-
tem, or a wiring harness or connector between 
the SWS monitor and the ECU. Check the wiring 
harness and connectors associated with the ECU 
and examine the ECU itself.

5. Service data on the SWS monitor

Select the defective function from the 
function-specific diagnostic menu, and check the 
service data that appears for each function item.
When the SWS communication line is monitored, 
you can determine whether the problem lies in the 
input or output signal circuit system by checking 
whether communication data is correct:

• If the switch condition does not meet the service 

data display, the input signal is defective.

• If the switch condition meets the service data dis-

play, the output signal system is defective.

NOTE:  In addition to the function-specific diag-
nostic menu, a service data menu is available for 
SWS monitor service data to check all items for 
each ECU.

6. Check the input signal circuit system

Check the relevant switch, sensor, input 
signal-side ECU and their wiring harness and 
connector.

7. Check the output signal circuit system

Check an output signal-side ECU, electrical load 
components and their wiring harness and 
connector.

SWS DIAGNOSIS

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-13

HOW TO CONNECT SWS MONITOR

M1549014800472

Required Special Tools:

•  MB991958: Scan 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: Probe Harness

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958. Connect 
the main harness A MB991910 before connecting the SWS 
monitor harness (for column-ECU) MB991812. Be sure to 
connect SWS monitor cartridge MB991806 after turning on 
the V.C.I. MB991924.
1. Ensure that the ignition switch is at the "LOCK" (OFF) 

position.

2. Start up the personal computer.
3. Connect special tool MB991827 to special tool MB991824 

and the personal computer.

4. Connect special tool MB991910 to special tool MB991824.
5. Connect special tool MB991910 to the data link connector.

6. Remove the steering column cover.
7. Remove the steering column switch connector.
8. Connect special tool MB991812 to the column switch 

connector.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC302210

COLUMN SWITCH 
CONNECTOR

COLUMN SWITCH 
CONNECTOR AT 
HARNESS SIDE 

MB991812

AB

SWS DIAGNOSIS

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-14

9. Connect special tool MB991812 to special tool MB991806.
10.Connect special tool MB991806 to special tool MB991824.
11.Turn the power switch of special tool MB991824 to the "ON" 

position.
NOTE: When special tool MB991824 is energized, special 
tool MB991824 indicator light will be illuminated in a green 
color.

12.Start the MUT-III system on the personal computer.

AC208681

MB991806

AB

MB991812

MB991824

MB991910

MB991827