Mitsubishi Galant 9G. Manual — part 1055

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-520

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

• MB991658: Test Harness Set

• MB991923: Power Plant ECU Check Harness

STEP 1. Using scan tool MB991958, check actuator test
item 04: No. 4 injector.

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) Start the engine and run at idle.
(3) Set scan tool MB991958 to the actuator testing mode for

item 04, No. 4 injector.

(4) Warm up the engine to normal operating temperature: 80

°C

to 95

°C (176°F to 203°F).

• The idle should become slightly rougher.

(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the actuator operating properly?

YES : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

− How to

Cope with Intermittent Malfunctions

P.00-14

.

NO : Go to Step 2.

STEP 2. Check the harness connector B-27 at No. 4
cylinder injector for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 3.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 10.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AK303110

M

1

2

CONNECTOR: B-27

B-27 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-521

STEP 3. Check the No. 4 cylinder injector.
(1) Disconnect the No.4 cylinder injector connector B-27.

(2) Measure the resistance between injector side connector

terminal No. 1 and No. 2.

Standard value: 10.5

− 13.5 ohms [at 20°C (68°F)]

Q: Is the measured resistance between 10.5 and 13.5 ohms

[at 20

°C (68°F)]?

YES : Go to Step 4.
NO : Replace the No. 4 cylinder injector. Then go to Step

10.

STEP 4. Measure the power supply voltage at No. 4
cylinder injector connector B-27.
(1) Disconnect connector B-27 and measure at the harness

side.

(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 1 and ground.

• Voltage should be battery positive voltage.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts)

present?
YES : Go to Step 6.
NO : Go to Step 5.

AK303110

M

1

2

CONNECTOR: B-27

B-27 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AB

AK000559

2

1

INJECTOR SIDE
CONNECTOR

AB

AK303110

M

1

2

CONNECTOR: B-27

B-27 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AB

AK303111

1

2

B-27 HARNESS
CONNECTOR:
COMPONENT SIDE

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-522

STEP 5. Check harness connector B-17X at MFI relay for
damage.
Q: Is the harness connector in good condition?

YES : Repair harness wire between MFI relay connector

B-17X (terminal No. 4) and No. 4 cylinder injector
connector B-27 (terminal No. 1) because of open
circuit or short circuit to ground.

Then go to Step 10.

NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 10.

1

2

3

4

AK303017

CONNECTOR: B-17X

FRONT OF VEHICLE

B-17X

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

RELAY BOX

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-523

STEP 6. Check for harness damage between MFI relay
connector B-17X (terminal No. 4) and No. 4 cylinder
injector connector B-27 (terminal No. 1).
Q: Is the harness wire in good condition?

YES : Go to Step 7.
NO : Repair it. Then go to Step 10.

1

2

3

4

AK303017

CONNECTOR: B-17X

FRONT OF VEHICLE

B-17X

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

RELAY BOX

AK303110

M

1

2

CONNECTOR: B-27

B-27 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AB