Mitsubishi Montero (2004+). Manual — part 223

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-379

STEP 4. Using scan tool MB991958, check data list item 25:
Barometric Pressure Sensor.

(1) Turn the ignition switch to the "ON" position.
(2) Set scan tool MB991958 to the data reading mode for item

25, Barometric Pressure Sensor.

• When altitude is 0 m (0 foot), 101 kPa (29.8 in.Hg.).

• When altitude is 600 m (1,969 feet), 95 kPa (28.1

in.Hg.).

• When altitude is 1,200 m (3,937 feet), 88 kPa (26.0

in.Hg.).

• When altitude is 1,800 m (5,906 feet), 81 kPa (23.9

in.Hg.).

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

YES : Go to Step 5.
NO : Refer to DTC P2227

− Barometric Pressure Circuit

Range/Performance Problem

P.13A-802

, DTC

P2228

− Barometric Pressure Circuit Low Input

P.13A-808

, DTC P0108

− Barometric Pressure Circuit

High Input

P.13A-822

.

STEP 5. Check harness connector B-44 at injector
intermediate connector for damage.

Q: Is the harness 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 10.

AK302970

AB

MB991911

MB991824

MB991827

AK200949

3

4

7

8

1

2

5

6

B-44(B)

CONNECTOR: B-44

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-380

STEP 6. Check the right bank injector resistance at
intermediate connector B-44.

(1) Disconnect the injector intermediate connector B-44.

(2) Measure the resistance between each injector side

connector terminal.

a. Measure the resistance between terminal No. 8 and No.

3 at No. 1 cylinder injector.

b. Measure the resistance between terminal No. 8 and No.

1 at No. 3 cylinder injector.

c. Measure the resistance between terminal No. 8 and No.

6 at No. 5 cylinder injector.

• Resistance should be between 13 and 16 ohms

[at 20

°C (68°F)].

Q: Is the measured resistance between 13 and 16 ohms [at

20

°C (68°F)]?

YES : Go to Step 8.
NO : Go to Step 7.

STEP 7. Check the right bank injector.

(1) Remove the intake manifold.
(2) Disconnect the right bank injector connector, which

deviates from the standard value at Step 6.

(3) Measure the resistance between injector side connector

terminal No. 1 and No. 2.

Standard value: 13

− 16 ohms [at 20°C (68°F)]

Q: Is the resistance between 13 and 16 ohms [at 20

°C

(68

°F)]?

YES : Repair harness wire between injector intermediate

connector and right bank injector connector because
of harness damage. Then go to Step 10.

NO : Replace the injector. Then go to Step 10.

AK200949

3

4

7

8

1

2

5

6

B-44(B)

CONNECTOR: B-44

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

AK000452

6

3 4
7 8

1 2
5

INJECTOR
INTERMEDIATE
CONNECTOR

AB

AK200949

3

4

7

8

1

2

5

6

B-44(B)

CONNECTOR: B-44

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

AKX01414AB

INJECTOR SIDE
CONNECTOR

1 2

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-381

STEP 8. Check the fuel pressure.

Refer to On-vehicle Service

− Fuel Pressure Test

P.13A-995

.

Q: Are there any abnormalities?

YES : Repair it. Then go to Step 10.
NO : Go to Step 9.

STEP 9. Replace the right bank injector.

(1) Replace the right bank injector.
(2) Carry out a test drive with the drive cycle pattern. Refer to

Diagnostic Function

− OBD-II Drive Cycle − Procedure 2 −

Fuel Trim Monitor

P.13A-4

.

(3) Read in the diagnostic trouble code (DTC).
Q: Is DTC P0172 set?

YES : Replace the PCM. Then go to Step 10.
NO : The inspection is complete.

STEP 10. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to

Diagnostic Function

− OBD-II Drive Cycle − Procedure 2 −

Fuel Trim Monitor

P.13A-4

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0172 set?

YES : Retry the troubleshooting.
NO : The inspection is complete.

DTC P0174: System too Lean (bank 2)

.

Fuel Trim Circuit

• Refer to DTC P0201 − P0206, Injector Circuit.

P.13A-421

.

CIRCUIT OPERATION

• Refer to DTC P0201 − P0206, Injector Circuit.

P.13A-421

.

TECHNICAL DESCRIPTION

• If a malfunction occurs in the fuel system, the fuel

trim value becomes too large.

• The PCM checks whether the fuel trim value is

within a specified range.

.

DESCRIPTIONS OF MONITOR METHODS
Left bank air/fuel learning value (long time fuel trim)

and air/fuel feedback integral value (short time
fuel trim) are too lean.

.

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)

• Misfire monitor

Sensor (The sensor below is determined to be

normal)

• Volume airflow sensor

• Engine coolant temperature sensor

• Intake air temperature sensor

• Barometric pressure sensor

• Throttle position sensor

.

AK200949

3

4

7

8

1

2

5

6

B-44(B)

CONNECTOR: B-44

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-382

DTC SET CONDITIONS

Logic Flow Chart

Check Conditions

• Engine coolant temperature is lower than approx-

imately 100

°C (212°F) when the engine is

started.

• Intake air temperature is lower than 60°C (140°F)

when the engine is started.

• Under the closed loop air/fuel ratio control.

• Engine coolant temperature is higher than 77°C

(171

°F).

• Volume airflow sensor output frequency is higher

than 100 Hz.

Judgment Criteria

• Long-term fuel trim has continued to be higher

than +12.5 percent for 5 seconds.

or

• Short-term fuel trim has continued to be higher

than +7.4 percent for 5 seconds.

Check Conditions

• Engine coolant temperature is lower than approx-

imately 100

°C (212°F) when the engine is

started.

• Intake air temperature is lower than 60°C (140°F)

when the engine is started.

• Under the closed loop air/fuel ratio control.

K

LRN

: LONG-TERM TRIM

K

I

: SHORT-TERM TRIM

K0 : MAXIMUM LIMIT OF LONG-TERM TRIM
K1 : MAXIMUM LIMIT OF SHORT-TERM TRIM
K2 : MINIMUM LIMIT OF LONG-TERM TRIM
K3 : MINIMUM LIMIT OF SHORT-TERM TRIM

START

MONITORING

CONDITIONS

END

NO

NO

NO

NO

NO

NO

YES

YES

YES

YES

YES

YES

K

LRN

> K0

MALFUNCTION

GOOD

K

LRN

< K2

K

I

< K3

K

I

> K1

CONTINUOUS FAILURE

FOR 5secs

AK302938