Mitsubishi Eclipse. Manual - part 618

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-1015

.

CIRCUIT OPERATION

• Battery positive voltage is applied to the MFI 

relay (terminals No. 1, No. 2).

• When the ignition switch is turned to the "ON" 

position, the battery positive voltage is applied to 
the ECM (terminal No. 99) <M/T> or PCM (termi-
nal No. 98) <A/T>. When the battery positive volt-
age is applied, the ECM <M/T> or PCM <A/T> 
turns the power transistor in the ECM <M/T> or 
PCM <A/T> "ON" and grounds the MFI relay coil. 

AK300244

CONNECTORS: C-55, C-59 <A/T>

AD

PCM

C-55 (GR)

C-59 (GR)

AK300091

CONNECTORS: C-58, C-62 <M/T>

ECM

AD

C-58 (GR)

C-62 (GR)

AK300754

1

2

CONNECTORS: B-01, B-02, B-05, B-06, 
                            B-25, B-26

AB

B-01 (GR)

B-05 (GR)

B-26 (GR)

B-02 (GR)

B-06 (GR)

B-25 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AK300116

CONNECTOR: C-87

AB

C-87

AK300092

CONNECTOR: C-07

AB

C-07

AK300121

MFI RELAY

CONNECTOR: A-18X

AB

A-18X

AK300124

CONNECTOR: C-111

AB

C-111

AK300125

CONNECTOR: C-112

AB

C-112

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-1016

With this, the MFI relay turns "ON" and the bat-
tery positive voltage is supplied to the ECM (ter-
minals No. 47, No. 59) <M/T> or PCM (terminals 
No. 41, No. 47) <A/T> from the MFI relay (termi-
nal No. 4).

• Battery positive voltage is constantly supplied to 

the ECM (terminal No. 60) <M/T> or PCM (termi-
nal No. 66) <A/T> as the backup power.

• The ECM (terminals No. 46, No. 58) <M/T> or 

PCM (terminals No. 42, No. 48) <A/T> is 
grounded to the vehicle body.

.

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

• Malfunction of the ignition switch.

• Malfunction of the MFI relay.

• Improper connector contact, open circuit or 

short-circuited harness wire.

• Disconnected ECM <M/T> or PCM <A/T> ground 

wire.

• Malfunction of the ECM <M/T> or PCM <A/T>.

DIAGNOSIS

STEP 1. Check connector A-18X at MFI relay for damage.
Q: Is the connector in good condition?

YES :  Go to Step 2.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then confirm that the 

malfunction symptom is eliminated.

AK300454

2

1

3

4

CONNECTOR: A-18X

AB

A-18X

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-1017

STEP 2. Check the MFI relay.
(1) Remove the MFI relay.

(2) Check for continuity between the MFI relay terminals 2 and 

3.

• There should be continuity. (approximately 70 Ω)

(3) Use jumper wires to connect MFI relay terminal 2 to the 

positive battery terminal and terminal 3 to the negative 
battery terminal.

(4) Check the continuity between the MFI relay terminals No. 1 

and No. 4 while connecting and disconnecting the jumper 
wire at the negative battery terminal.

• Should be less than 2 ohms. (Negative battery terminal 

connected)

• Should be open loop. (Negative battery terminal discon-

nected)

(5)  Install the MFI relay.
Q: Is the measured voltage within the specified range?

YES : Go to Step 3.
NO :  Replace the MFI relay. Then confirm that the 

malfunction symptom is eliminated.

AK300454

2

1

3

4

CONNECTOR: A-18X

AB

A-18X

HARNESS CONNECTOR:
COMPONENT SIDE

AK204164

1

2

3

4

MFI RERAY 
SIDE 
CONNECTOR

AB

1

2

3

4

AK203257

MFI RELAY SIDE
CONNECTOR

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-1018

STEP 3. Check the power supply voltage at MFI relay 
harness side connector A-18X.
(1) Disconnect the connector A-18X and measure at the 

harness side.

(2) Measure the voltage between terminal No. 1, No. 2 and 

ground.

• Voltage should be battery positive voltage.

Q: Is battery positive voltage (approximately 12 volts) 

present?
YES : Go to Step 4.
NO :  Check harness connector C-07 at intermediate 

connector for damage, and repair or replace as 
required. Refer to, GROUP 00E, Harness Connector 
Inspection 

P.00E-2

. If intermediate connector is in 

good condition, repair harness wire between fusible 
link (3) and MFI relay connector A-18X terminal 1, 2 
because of open circuit. Then confirm that the 
malfunction symptom is eliminated.

AK300454

2

1

3

4

CONNECTOR: A-18X

AB

A-18X

HARNESS CONNECTOR:
COMPONENT SIDE

2

1

3

4

AK203258

B-18X HARNESS 
CONNECTOR: 
COMPONENT SIDE

AC