Mitsubishi Galant (2004+). Manual — part 1503

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CHASSIS ELECTRICAL

54A-255

Past trouble

• Carry out diagnosis with particular emphasis on

connector(s) or wiring harness in the CAN bus
lines between the ETACS-ECU and the
multi-center display unit (middle grade type), and
the power supply system to the ETACS-ECU. For
diagnosis procedures, refer to "How to cope with
past trouble" (Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

P.00-6

).

NOTE: For a past trouble, you may not find it by
the MUT-III CAN bus diagnostics even if there is
any failure in CAN bus lines. In this case, refer to
GROUP 00, How to Use Troubleshooting/Inspec-
tion Service Points-How to Cope with Intermittent

Malfunction

P.00-6

.) and check the CAN bus

lines. You can narrow down the possible cause of
the trouble by referring to the DTC, which is set
regarding the CAN communication-linked ECUs
(Refer to GROUP 54C, CAN bus line Diagnostics
Flow

P.54C-6

).

.

TROUBLESHOOTING HINTS

• The wiring harness or connectors may have

loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector.

• Malfunction of ETACS-ECU

• Malfunction of multi-center display unit (middle

grade type)

DIAGNOSIS

Required Special Tools:

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

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

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness A (Vehicles with CAN

communication system)

STEP 1. Using scan tool MB991958, diagnose the CAN bus
line.
Use scan tool MB991958 to diagnose the CAN bus lines.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to "ON" position.
(3) Diagnose the CAN bus line.
Q: Is the check result satisfactory?

YES : Go to Step 2.
NO : Repair the CAN bus lines. (Refer to GROUP 54C,

Diagnosis-Can Bus Diagnostic Chart

P.54C-14

). On

completion, go to Step 6.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

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CHASSIS ELECTRICAL

54A-256

STEP 2. Using scan tool MB991958, read ETACS-ECU
diagnostic trouble code
Check that the ETACS-ECU sets a DTC.
Q: Is the DTC set?

YES : Diagnose the SWS system by referring to GROUP

54B, SWS Diagnosis

− Diagnostic Trouble Code

Chart

P.54B-27

.

NO : Go to Step 3.

STEP 3. Using scan tool MB991958, read the diagnostic
trouble code.
Check if a DTC, which relates to CAN communication-linked
systems below, is set.
Combination meter

• DTC 019: ETACS-ECU time-out

Q: Is the DTC set?

YES : Go to Step 4.
NO : Go to Step 5.

STEP 4. Recheck for diagnostic trouble code.
Recheck if the DTC is set.

1. Erase the DTC.
2. Turn the ignition switch to "ON" position.
3. Check if the DTC is set.

Q: Is the check result satisfactory?

YES : A poor connection, open circuit or other intermittent

malfunction is present in the CAN bus lines between
the ETACS-ECU and the multi-center display unit
(middle grade type) (Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points-How to
Cope with Intermittent Malfunction

P.00-6

).

NO : Replace ETACS-ECU and then go to step 6.

STEP 5. Recheck for diagnostic trouble code.
Recheck if the DTC is set.

1. Erase the DTC.
2. Turn the ignition switch to "ON" position.
3. Check if the DTC is set.

Q: Is the check result satisfactory?

YES : A poor connection, open circuit or other intermittent

malfunction is present in the CAN bus lines between
the ETACS-ECU and the multi-center display unit
(middle grade type) (Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points-How to
Cope with Intermittent Malfunction

P.00-6

).

NO : Replace multi-center display unit (middle grade type)

and then go to step 6.

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CHASSIS ELECTRICAL

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STEP 6. Recheck for diagnostic trouble code.
Recheck if the DTC is set.

1. Erase the DTC.
2. Turn the ignition switch to "ON" position.
3. Check if the DTC is set.

Q: Is the check result satisfactory?

YES : The procedure is complete.
NO : Go to Step 1.

DTC 020: Failures Information on Powertrain Control Module (Related to Engine)

CAUTION

If DTC 20 is set in the multi-center display,
always diagnose the CAN bus lines.

.

CIRCUIT OPERATION
Refer to

P.54A-238

.

.

DTC SET CONDITION
The multi-center display unit (middle grade type)
communicates with the powertrain control module via
CAN bus lines. If failure information is sent to the
multi-center display unit (middle grade type), DTC 20
will be set.

.

TECHNICAL DESCRIPTION (COMMENT)

Current trouble

• The powertrain control module or the multi-center

display unit (middle grade type) may be defec-
tive.

Past trouble

• Carry out diagnosis with particular emphasis on

connector(s) or wiring harness between the
powertrain control module and the vehicle speed
sensor. For diagnosis procedures, refer to "How
to cope with past trouble" (Refer to GROUP 00,
How to Use Troubleshooting/Inspection Service
Points

P.00-6

).

.

TROUBLESHOOTING HINTS

• The wiring harness or connectors may have

loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector.

• Malfunction of powertrain control module

• Malfunction of multi-center display unit (middle

grade type)

DIAGNOSIS

Required Special Tools:

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

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

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness A (Vehicles with CAN

communication system)

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CHASSIS ELECTRICAL

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STEP 1. Using scan tool MB991958, diagnose the CAN bus
line.
Use scan tool MB991958 to diagnose the CAN bus lines.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to "ON" position.
(3) Diagnose the CAN bus line.
Q: Is the check result satisfactory?

YES : Go to Step 2.
NO : Repair the CAN bus lines (Refer to GROUP 54C,

Diagnosis-Can Bus Diagnostic Chart

P.54C-14

). On

completion, go to Step 6.

STEP 2. Using scan tool MB991958, read MFI system
diagnostic trouble code.
Check if an MFI system DTC is set.
Q: Is the DTC set?

YES : Diagnose the MFI system by referring to GROUP13A,

MFI Diagnosis

− Diagnostic Trouble Code Chart

P.13A-34

or GROUP13B, MFI Diagnosis

− Diagnostic

Trouble Code Chart

P.13B-33

.

NO : Go to Step 3.

STEP 3. Using scan tool MB991958, read the diagnostic
trouble code related to the other system.
Check if a DTC, which relates to CAN communication-linked
systems below, is set.
ABS-ECU

• DTC U1120: Failure information on powertrain control

module (related to engine) <vehicles with TCL>

Combination meter

• DTC 020: Failure information on powertrain control

module (related to engine)

A/C-ECU

• DTC U1120: Failure information on powertrain control

module (related to engine)

Q: Is the DTC set?

YES : Go to Step 4.
NO : Go to Step 5.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827