Mitsubishi Galant (2004+). Manual — part 1444

IGNITION SWITCH

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CHASSIS ELECTRICAL

54A-19

SYMPTOM PROCEDURES

INSPECTION PROCEDURE 1: Communication with Scan Tool MB991958 is Impossible.

MFI
RELAY

POWERTRAIN
CONTROL
MODULE (PCM)

POWER
SUPPLY

JOINT
CONNECTOR (2)

IMMOBILIZER-
ECU

Immobilizer-ECU Power Supply, Ground and PCM CommunicationLine Circuit

IGNITION SWITCH

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CHASSIS ELECTRICAL

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.

CIRCUIT OPERATION
The Immobilizer-ECU is energized by the MFI relay
when the ignition switch is turned "ON". The PCM
transmits a signal from scan tool MB991958 to the
immobilizer-ECU as it is. In the same way, a signal
from the immobilizer-ECU is also transmitted to scan
tool MB991958 as it is.

.

TECHNICAL DESCRIPTION (COMMENT)

• This malfunction may be caused by a defective

immobilizer-ECU, PCM, or a defect in the com-
munication line between the immobilizer-ECU
and PCM. If this malfunction appears when the
MFI system and scan tool MB991958 can com-
municate each other, MFI system DTC P0513 will
reset.

• If the MFI system is normal, the MFI relay can be

determined as normal. In addition, if the MFI sys-
tem and scan tool MB991958 can communicate
each other, the circuits between the data link con-
nector and the PCM can determined as normal.
NOTE: If this malfunction appears, MFI system
DTC P0513 will be output.

.

TROUBLESHOOTING HINTS

• Malfunction of the immobilizer-ECU

• Malfunction of the PCM

• The wiring harness or connectors may have

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

.

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• 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)

AC305210

CONNECTOR: A-13

AS

A-13 (GR)

AC305977

CONNECTOR: B-17X

AM

AC305229AE

CONNECTOR: B-19

B-19 (B)

AC305231

CONNECTORS: C-03, C-29, C-124

CS

C-03

C-29

C-124

IGNITION SWITCH

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STEP 1. Using scan toll MB991958, read the MFI system
diagnostic trouble code.

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to "LOCK" (OFF) position before connect-
ing or disconnecting scan tool.
Use scan tool MB991958 to confirm the MFI system DTC.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch "ON" to position.
(3) Read the MFI system diagnosis code.

NOTE: If the scan tool MB991958 cannot communicate
with the MFI system, refer to GROUP 13A, MFI Diagnosis

−

Symptom Procedures

P.13A-944

or GROUP 13B, MFI

Diagnosis

−

Symptom Procedures

P.13B-968

.

Q: Is an MFI system DTC P0513 output?

YES : Refer to GROUP 13A, MFI Diagnosis

− Diagnostic

Trouble Code Chart

P.13A-753

or GROUP 13B, MFI

Diagnosis

− Diagnostic Trouble Code Chart

P.13B-796

.

NO : Go to Step 2.

STEP 2. Check the immobilizer-ECU power supply circuit
by backprobing.

(1) Do not disconnect immobilizer-ECU connector C-124.
(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal 1 and ground by

backprobing.

• The voltage should measure approximately 12 volts

(battery positive voltage).

Q: Is the measured voltage approximately 12 volts (battery

positive voltage)?
YES : Go to Step 5.
NO : Go to Step 3.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC305231CQ

CONNECTOR: C-124

HARNESS SIDE

AC209365HR

CONNECTOR C-124
(HARNESS SIDE)

IGNITION SWITCH

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CHASSIS ELECTRICAL

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STEP 3. Check immobilizer-ECU connector C-124 and MFI
relay connector B-17X for loose, corroded or damaged
terminals, or terminals pushed back in the connector.

Q: Are immobilizer-ECU connector C-124 and MFI relay

connector B-17X in good condition?
YES : Go to Step 4.
NO : Repair or replace the component(s). Refer to GROUP

00E, Harness Connector Inspection

P.00E-2

. Confirm

that scan tool MB991958 communicates normally.

AC305977

RELAY BOX SIDE

CONNECTOR: B-17X

AM

AC305231CQ

CONNECTOR: C-124

HARNESS SIDE