Mitsubishi Montero (2002-2004). Manual - part 646

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-281

TROUBLESHOOTING HINTS (The most likely 

causes for this code to be set are: )

• Volume airflow sensor failed.

• Injector (Number 1, 3, 5) failed.

• Incorrect fuel pressure.

• Air drawn in from gaps in gasket, seals, etc.

• Right bank heated oxygen sensor failed.

• Engine coolant temperature sensor failed.

• Intake air temperature sensor failed.

• Barometric pressure sensor failed.

• Exhaust leak.

• Use of incorrect or contaminated fuel.

• PCM failed.

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, check data list item 12: 
Volume Airflow Sensor.

CAUTION

To prevent damage to scan tool MB991502, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Start the engine and run at idle.
(3) Set scan tool MB991502 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).

• When idling, between 17 and 43 Hz (between 3.5 and 

7.5 gm/s).

• When 2,500 r/min, between 64 and 104 Hz (between 

13.6 and 19.6 gm/s).

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

YES : YES: Go to Step 2.
NO :  Refer to , DTC P0101 

− Volume Airflow Circuit Range/

Performance Problem 

P.13Ac-2

, DTC P0102 

− 

Volume Airflow Circuit Low Input 

P.13Ac-9

.

STEP 2. Using scan tool MB991502, check data list item 13: 
Intake Air Temperature Sensor.
(1) Turn the ignition switch to the "ON" position.
(2) Set scan tool MB991502 to the data reading mode for item 

13, Intake Air Temperature Sensor.

• The intake air temperature and temperature shown with 

the scan tool should approximately match.

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

YES : Go to Step 3.
NO :  Refer to , DTC P0111 

− Intake Air Temperature Circuit 

Range/Performance Problem 

P.13Ac-44

, DTC P0112 

− Intake Air Temperature Circuit Low Input 

P.13Ac-50

, 

DTC P0113 

− Intake Air Temperature Circuit High 

Input 

P.13Ac-54

.

ACX01539

16-PIN

MB991502

AC

ACX01539

16-PIN

MB991502

AC

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-282

STEP 3. Using scan tool MB991502, check data list item 21: 
Engine Coolant Temperature Sensor.
(1) Turn the ignition switch to the "ON" position.
(2) Set scan tool MB991502 to the data reading mode for item 

21, Engine Coolant Temperature Sensor.

• The engine coolant temperature and temperature 

shown with the scan tool should approximately match.

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

YES : Go to Step 4.
NO :  Refer to , DTC P0116 

− Engine Coolant Temperature 

Circuit Range/Performance Problem

P.13Ac-60

, DTC 

P0117 

− Engine Coolant Temperature Circuit Low 

Input 

P.13Ac-70

, DTC P0118 

− Engine Coolant 

Temperature Circuit High Input 

P.13Ac-74

.

STEP 4. Using scan tool MB991502, check data list item 25: 
Barometric Pressure Sensor.
(1) Turn the ignition switch to the "ON" position.
(2) Set scan tool MB991502 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 P0106 

− Barometric Pressure Circuit 

Range/Performance Problem 

P.13Ac-17

,  DTC 

P0107 

− Barometric Pressure Temperature Circuit 

Low Input 

P.13Ac-22

, DTC P0108 

− Barometric 

Pressure Temperature Circuit High Input 

P.13Ac-35

.

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.

ACX01539

16-PIN

MB991502

AC

ACX01539

16-PIN

MB991502

AC

AK200949

3

4

7

8

1

2

5

6

B-44(B)

CONNECTOR: B-44

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-283

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 when measuring No. 1 cylinder injector.

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

1 when measuring No. 3 cylinder injector.

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

6 when measuring 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

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-284

STEP 8. Check the fuel pressure.
Refer to GROUP 13A, On-vehicle Service 

− Fuel Pressure Test 

P.13Aa-13

.

Q: Are there any abnormalities?

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

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 

GROUP 13A, Procedure 2 

− Fuel Trim Monitor 

P.13Ab-2

.

(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 

GROUP 13A, Procedure 2 

− Fuel Trim Monitor 

P.13Ab-2

.

(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.13Ac-318

.

CIRCUIT OPERATION

• Refer to DTC P0201 − P0206, Injector Circuit. 

P.13Ac-318

.

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.

.

DTC SET CONDITIONS

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 100 Hz 

or more.

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.

AK200949

3

4

7

8

1

2

5

6

B-44(B)

CONNECTOR: B-44

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE