Mitsubishi 380. Manual - part 549

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MFI)

13A-288

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

• No. 3 cylinder injector failed.

• Open or shorted to ground No.3 cylinder injector 

circuit.

• Shorted to battery, No.3 cylinder injector circuit.

• Harness or connector damage.

• Refer to component locations GROUP-

70

• Refer to configuration diagrams GROUP-

80

• Refer to circuit diagrams GROUP-

90

DIAGNOSIS

Required Special Tools:

• Diagnostic Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

• MB991658: Test Harness
• MB992044: Power Plant ECU Check Harness

STEP 1. Using diagnostic tool , check actuator test item 
03: No. 3 injector.

CAUTION

To prevent damage to diagnostic tool , always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting diagnostic tool .
(1) Connect diagnostic tool to the data link connector.
(2) Start the engine and run at idle.
(3) Set diagnostic tool to the actuator testing mode for item 03, 

No. 3 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: Does the idle vary or engine run "rough"?

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 harness connector B-32 at intermediate 
connector 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 12.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AK303053

3

4

5

8

9

1

2

6

7

10

CONNECTOR: B-32

HARNESS CONNECTOR:

COMPONENT SIDE

AB

B-32 (B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MFI)

13A-289

STEP 3. Check the No. 3 cylinder injector resistance at 
intermediate connector B-32.
(1) Disconnect the intermediate connector B-32.

(2) Measure the resistance between terminal No. 9 and No. 10.

• Resistance should be between 10.5 and 13.5 ohms.

Q: Is the measured resistance between 10.5 and 13.5 

ohms?
YES : Go to Step 6.
NO :  Go to Step 4.

STEP 4. Check the connector B-03 at No. 3 cylinder 
injector for damage.
Remove the intake manifold.

Q: Is the harness connector in good condition?

YES : Go to Step 5.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 12.

AK303053

3

4

5

8

9

1

2

6

7

10

CONNECTOR: B-32

HARNESS CONNECTOR:

COMPONENT SIDE

AB

B-32 (B)

1 2 3
6 7 8

4 5
9 10

AK303107

B-32 

INTERMEDIATE

CONNECTOR

AB

AK303108

M

1

2

CONNECTOR: B-03

AB

B-03 (GR)

HARNESS CONNECTOR:

COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MFI)

13A-290

STEP 5. Check the No. 3 cylinder injector.
(1) Disconnect the No. 3 cylinder injector connector B-03.

(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 : Repair harness wire between intermediate connector 

B-32 (terminal No. 9) and injector connector B-03 
(terminal No. 1) and harness wire between No.3 
cylinder injector connector B-03 (terminal No. 2) 
and intermediate connector B-32 (terminal No. 10) 
because of open circuit or short circuit to ground 
or harness damage.

Then go to Step 12.

NO :  Replace the No.3 cylinder injector. Then go to Step 

12.

AK303108

M

1

2

CONNECTOR: B-03

AB

B-03 (GR)

HARNESS CONNECTOR:

COMPONENT SIDE

AK000559

2

1

INJECTOR SIDE
CONNECTOR

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MFI)

13A-291

STEP 6. Measure the power supply voltage at intermediate 
connector B-32.
(1) Disconnect the connector B-32 and measure at the female 

connector side.

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

(3) Measure the voltage between terminal No. 9 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 8.
NO :  Go to Step 7.

STEP 7. 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 intermediate connector 
B-32 (terminal No. 9) because of open circuit or short 
circuit to ground. Then go to Step 12.

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

Connector Inspection 

P.00E-2

. Then go to Step 12.

AK303053

3

4

5

8

9

1

2

6

7

10

CONNECTOR: B-32

HARNESS CONNECTOR:

COMPONENT SIDE

AB

B-32 (B)

3

4

5

8

9

1

2

6

7

10

AK203172

B-32 HARNESS 

CONNECTOR: 

COMPONENT

SIDE

AB

1

2

3

4

AK303017

CONNECTOR: B-17X

FRONT OF VEHICLE

B-17X

AB

HARNESS

CONNECTOR:

COMPONENT SIDE

RELAY BOX