Mitsubishi Montero Sport (2004+). Manual - part 354

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-829

.

COMMENT

• The battery positive voltage is applied on the igni-

tion coil by the ignition switch-IG.

• When the PCM turns the power transistor in the 

PCM "OFF," battery positive voltage is applied on 
the ignition power transistor (terminals No. 1, No. 
2 and No. 3), and the ignition power transistor 
turns "ON."

• When the ignition power transistor turns "ON", 

the ignition coil's primary circuit is grounded by 
the ignition power transistor terminal No. 4. Then 
the primary current flows to the ignition coil.

AK200051

CONNECTORS: A-05, A-06

A-05(B)

AB

A-06(B)

AK200051

CONNECTORS: A-44, A-45, A-46

A-44(B) A-45(B)

AC

A-46(B)

AK103738AB

CONNECTORS: C-89, C-90

PCM

C-89(GR) C-90(GR)

AK200052 AB

CONNECTOR: A-37

ENGINE SPEED
DETECTION
CONNECTOR

A-37(L)

AK103912AB

CONNECTOR: C-71

C-71

AK200035AB

CONNECTOR: D-08

D-08

JUNCTION BLOCK
(REAR SIDE)

AK200040AB

CONNECTOR: D-15

D-15(B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-830

.

TROUBLESHOOTING HINTS (The most likely 
causes for this case: )

• Malfunction of the ignition coil.

• Malfunction of the ignition power transistor.

• Improper connector contact, open circuit or 

short-circuited harness wire.

• Malfunction of the PCM.

DIAGNOSIS

STEP 1. Check harness connectors A-44, A-45, A-46 at 
ignition coil for damage.
Q: Is the harness 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.

STEP 2. Check the ignition coil.
Refer to GROUP 16, Ignition System 

− Ignition Coil Check 

P.16-32

.

Q: Are there any abnormalities?

YES : Go to Step 3.
NO :  Replace the ignition coil. Then confirm that the 

malfunction symptom is eliminated.

STEP 3. Check harness connectors A-05, A-06 at ignition 
power transistor for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 4. 
NO :  Refer to GROUP 00E, Harness Connector Inspection 

P.00E-2

. Then confirm that the malfunction symptom 

is eliminated.

AK200053

1

2

CONNECTORS: A-44, A-45, A-46

A-44(B)

A-45(B)

A-46(B)

AB

HARNESS 
CONNECTOR:
COMPONENT SIDE

AK200054

11

13 12

3

4

5

6

1

2

CONNECTORS: A-05, A-06

A-05(B)

AB

A-06(B)

A-06 HARNESS CONNECTOR:
COMPONENT SIDE

A-05 HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-831

STEP 4. Check the ignition power transistor.
Refer to GROUP 16, Ignition System 

− Ignition Coil Power 

Transistor Continuity Check 

P.16-32

.

Q: Are there any abnormalities?

YES : Go to Step 5.
NO :  Replace the ignition power transistor. Then confirm 

that the malfunction symptom is eliminated.

STEP 5. Measure the power supply voltage at ignition coil 
connectors A-44, A-45, A-46.
(1) Disconnect the connectors A-44, A-45, A-46 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 :  Check harness connector D-08 at intermediate 

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

P.00E-2

. If intermediate connector D-08 is in good 

condition, repair harness wire between ignition switch 
connector D-15 (terminal No. 2) and ignition coil 
connectors A-44, A-45, A-46 (terminal No. 1). Then 
confirm that the malfunction symptom is eliminated.

AK200053

1

2

CONNECTORS: A-44, A-45, A-46

A-44(B)

A-45(B)

A-46(B)

AB

HARNESS 
CONNECTOR:
COMPONENT SIDE

AK000723

1

2

A-44, A-45, A-46 
HARNESS CONNECTOR: 
COMPONENT SIDE 

AC

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-832

STEP 6. Measure the power supply voltage at ignition 
power transistor connector A-06.
(1) Disconnect the connector A-06 and measure at the harness 

side.

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

(3) Measure the voltage between terminals No. 11, No. 12, No. 

13 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 7.
NO :  Repair harness wire between ignition coil connectors 

A-44, A-45, A-46 (terminal No. 2) and ignition power 
transistor connector A-06 (terminals No. No. 11, No. 
12, No. 13). Then confirm that the malfunction 
symptom is eliminated.

STEP 7. Measure the power supply voltage at ignition 
power transistor connector A-05.
(1) Disconnect the connector A-05 and measure at the harness 

side.

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

(3) Measure the voltage between terminal No. 6 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 :  Check harness connector D-08 at intermediate 

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

P.00E-2

. If intermediate connector D-08 is in good 

condition, repair harness wire between ignition switch 
connector D-15 (terminal No. 2) and ignition power 
transistor connector A-05 (terminal No. 6). Then 
confirm that the malfunction symptom is eliminated.

AK200474

11

13 12

CONNECTOR: A-06

AB

HARNESS 
CONNECTOR:
COMPONENT 
SIDE

A-06(B)

AKX01510AE

A-06 HARNESS 
CONNECTOR: 
COMPONENT SIDE

11

12

13

AK200475

3

4

5

6

1

2

CONNECTOR: A-05

AB

HARNESS 
CONNECTOR:
COMPONENT 
SIDE

A-05(B)

AKX01444

A-05 HARNESS 
CONNECTOR: 
COMPONENT SIDE

1

2

3

4

5

6

AE