Mitsubishi Montero Sport (2004+). Manual - part 158

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-45

STEP 1. Using scan tool MB991958, check data list item 12: 
Volume Airflow Sensor.

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 data reading mode for  item 

12, Volume Airflow Sensor.

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

°C 

to 95

°C (176°F to 203°F).

• The standard value during idling should be 10 Hz or 

more.

• When the engine is revved, the frequency should 

increase according to the increase in engine speed.

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

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

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

P.00-7

.

NO :  Go to Step 2.

STEP 2. Measure the power supply voltage at volume 
airflow sensor connector A-01 by backprobing.
(1) Do not disconnect the connector A-01.
(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 4 and ground by 

backprobing.

• 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 5.
NO :  Go to Step 3.

AK303629AB

MB991911

MB991827

MB991824 

16-PIN

AK103913

3

4

5

1

2

6

7

CONNECTOR: A-01

A-01(B)

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

AKX01514 AO

A-01 HARNESS 
CONNECTOR: 
HARNESS SIDE

1 2 3 4 5 6 7

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-46

STEP 3. Measure the power supply voltage at volume 
airflow sensor harness side connector A-01.
(1) Disconnect the connector A-01 and measure at the harness 

side.

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

(3) Measure the voltage between terminal No. 4 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 4.
NO :   Check connector C-14 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 MFI relay 
connector C-59 (terminal No. 1) and volume airflow 
sensor connector A-01 (terminal No. 4) because of 
open circuit or short circuit to ground. Then go to Step 
13.

STEP 4. Check connector A-01 at the volume airflow 
sensor for damage.
Q: Is the connector in good condition?

YES : Check connector C-14 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 MFI relay 
connector C-59 (terminal No. 1) and volume airflow 
sensor connector A-01 (terminal No. 4) because of 
harness damage. Then go to Step 13.

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

Connector Inspection 

P.00E-2

. Then go to Step 13.

AK103913

3

4

5

1

2

6

7

CONNECTOR: A-01

A-01(B)

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

AKX01405

A-01 HARNESS CONNECTOR: 
COMPONENT SIDE

7 6 5 4 3 2 1

AM

AK103913

3

4

5

1

2

6

7

CONNECTOR: A-01

A-01(B)

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-47

STEP 5. Check connector A-01 at volume airflow sensor 
for damage.
Q: Is the connector in good condition?

YES : Go to Step 6.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 13.

STEP 6. Measure the sensor supply voltage at volume 
airflow sensor harness side connector A-01.
(1) Disconnect the connector A-01 and measure at the harness 

side.

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

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

•  Voltage should be between 4.8 and 5.2 volts.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.8 and 5.2 volts?

YES : Go to Step 9.
NO :  Go to Step 7.

STEP 7. Check connector C-90 at PCM for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 8.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 13.

AK103913

3

4

5

1

2

6

7

CONNECTOR: A-01

A-01(B)

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

AK103913

3

4

5

1

2

6

7

CONNECTOR: A-01

A-01(B)

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

AKX01406 AK

A-01 HARNESS CONNECTOR: 
COMPONENT SIDE

7 6 5 4 3 2 1

AK103762

42

43

48

49

50

51

52

53

54

55

56

57

46 45 44

58

59

60

61

62

63

64

65

66

47

41

AB

CONNECTOR: C-90

C-90(GR)

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-48

STEP 8. Check for short circuit to ground between volume 
airflow sensor connector A-01 (terminal No. 3) and PCM 
connector C-90 (terminal No. 65).
Q: Is the harness wire in good condition?

YES : Replace the PCM. Then go to Step 13.
NO :  Repair it. Then go to Step 13.

STEP 9. Check for continuity at volume airflow sensor 
harness side connector A-01.
NOTE: Check harness after checking intermediate connector 
C-71. If intermediate connector is damaged, repair or replace it. 
Refer to GROUP 00E, Harness Connector Inspection 

P.00E-2

. 

Then go to Step 13.

AK103913

3

4

5

1

2

6

7

CONNECTOR: A-01

A-01(B)

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

AK103762

42

43

48

49

50

51

52

53

54

55

56

57

46 45 44

58

59

60

61

62

63

64

65

66

47

41

AB

CONNECTOR: C-90

C-90(GR)

HARNESS CONNECTOR:
COMPONENT SIDE