Mitsubishi Galant 9G. Manual - part 1060

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-540

.

CIRCUIT OPERATION

• The injector power is supplied from the MFI relay 

(terminal No. 4).

• The PCM controls the injector by turning the 

power transistor in the PCM "ON" and "OFF".

.

TECHNICAL DESCRIPTION

• The amount of fuel injected by the injector is con-

trolled by the amount of continuity time the coil is 
grounded by the PCM.

• A surge voltage is generated when the injectors 

are driven and the current flowing to the injector 
coil is shut off.

• The PCM checks this surge voltage.

.

DESCRIPTIONS OF MONITOR METHODS

Off-surge does not occur after injector is operated.

.

MONITOR EXECUTION

Continuous

.

MONITOR EXECUTION CONDITIONS 
(Other monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Not applicable

Sensor (The sensor below is determined to be 

normal)

• Not applicable

.

AK303115

CONNECTOR: B-26

B-26 (GR)

AB

1

2

3

4

1

2

3

4

1

2

3

4

1

2

3

4

AK303014

CONNECTOR: B-17X

MFI RELAY

MFI RELAY

FRONT OF VEHICLE

B-17X

AB

AK303059

CONNECTOR: B-23

PCM

AB

AIR CLEANER

B-23

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-541

DTC SET CONDITIONS <Circuit continuity 

− open circuit and shorted low>

Logic Flow Chart

.

Check Conditions

• Engine is running.

Judgment Criteria

• The supply voltage is 3 volts or less without the 

injector driving.

.

START

END

NO

NO

NO

YES

YES

YES

MALFUNCTION

GOOD

MONITORING

CONDITIONS

CONTINUOUS

FAILURE FOR 2secs

INJ. SURGE V

<= 3 V

AK401614

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-542

DTC SET CONDITIONS <Circuit continuity 

− shorted high>

Logic Flow Chart

.

Check Conditions

• Engine is running.

Judgment Criteria

• The coil current is 4 ampere or more with the 

injector driving.

.

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function 

− OBD-II Drive Cycle − 

Procedure 6 

− Other Monitor 

P.13B-6

.

.

TROUBLESHOOTING HINTS (The most 
likely causes for this code to be set are:)

• No. 6 cylinder injector failed.

• Open or shorted No. 6 cylinder injector circuit, 

harness damage, or connector damage.

• PCM failed.

START

END

NO

NO

NO

YES

YES

YES

MALFUNCTION

GOOD

MONITORING

CONDITIONS

CONTINUOUS

FAILURE FOR 2secs

CURRENT

>= 4 A

AK401592

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-543

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

• MB991923: Power Plant ECU Check Harness

STEP 1. Using scan tool MB991958, check actuator test 
item 02, 04, 06: No. 6 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 06, No. 6 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-26 at No. 6 
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

AK303116

M

1

2

CONNECTOR: B-26

B-26 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AB