Mitsubishi Montero (2004+). Manual - part 378

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-999

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. Check the operation of the fuel pump by using scan tool 

MB991958 to force-drive the fuel pump.

2. If the fuel pump will not operate, check by using the 

following procedure, and if it is normal, check the drive 
circuit.

(1) Turn the ignition switch to the "LOCK" (OFF) position.

(2) Remove fuel pump relay (2). 

Connect terminal number 3 of the harness-side 
connector to the battery.
Check if the fuel pump operation sound can be heard at 
this time.
NOTE: As the fuel pump is an in-tank type, the fuel pump 
sound is hard to hear, so remove the fuel filler cap and 
check from the tank inlet.

(3) Check the fuel pressure by pinching the fuel hose with 

the fingertips.

(4) Install fuel pump relay (2).

MULTIPORT FUEL INJECTION (MFI) RELAY, 
THROTTLE ACTUATOR CONTROL MOTOR 
RELAY AND FUEL PUMP RELAY CONTINUITY 
CHECK

M1131052000028

AC306409AF

MB991911

MB991824

MB991827

AC203984

1

2

3

4

FUEL PUMP RELAY (2) 
HARNESS SIDE CONNECTOR

AB

BATTERY 
VOLTAGE

BATTERY POWER 
SUPPLY 
TERMINAL

SPECIFIED 
CONDITION

Supplied

2-4

1-3

Not supplied

−

2-4

1

2

3

4

AK201511AB

MFI RELAY SIDE
CONNECTOR

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-1000

INTAKE AIR TEMPERATURE SENSOR CHECK

M1131002800546

1. Disconnect the volume airflow sensor connectors.
2. Measure resistance between terminals 5 and 6.

Standard value:

13 

− 17 kΩ [at -20°C (-4°F)]

5.3 

− 6.7 kΩ [at 0°C (32°F)]

2.3 

− 3.0 kΩ [at 20°C (68°F)]

1.0 

− 1.5 kΩ [at 40°C (104°F)]

0.56 

− 0.76 kΩ [at 60°C (140°F)]

0.30 

− 0.42 kΩ [at 80°C (176°F)]

3. If not within specifications, replace the volume airflow 

sensor.

4. Measure resistance while heating the sensor using a hair 

dryer.

Normal condition:

5. If resistance does not decrease as heat increases, replace 

the volume airflow sensor assembly.

ENGINE COOLANT TEMPERATURE SENSOR 
CHECK

M1131003100517

CAUTION

Be careful not to touch the connector (resin section) with 
the tool when removing and installing.
1. Drain engine coolant, then remove the engine coolant 

temperature sensor.

2. With the temperature sensing portion of engine coolant 

temperature sensor immersed in hot water, check the 
resistance.

Standard value:

14 

− 17 kΩ [at -20°C (-4°F)]

5.1 

− 6.5 kΩ [at 0°C (32°F)]

2.1 

− 2.7 kΩ [at 20°C (68°F)]

0.9 

− 1.3 kΩ [at 40°C (104°F)]

0.48 

− 0.68 kΩ [at 60°C (140°F)]

0.26 

− 0.36 kΩ [at 80°C (176°F)]

3. If resistance deviates from the standard value greatly, 

replace the sensor.

4. Apply 3M

 AAD part number 8731 or equivalent to threaded 

portion.

5. Install the engine coolant temperature sensor and tighten it 

to the specified torque.

Tightening torque: 29 

± 10 N⋅m (22 ± 7 ft-lb)

TEMPERATURE

RESISTANCE (k

Ω)

Higher

Smaller

AKX01407AB

INTAKE AIR TEMPERATURE
SENSOR SIDE CONNECTOR

1 2 3 4 5 6 7

AKX01621 AB

INTAKE AIR
TEMPERATURE
SENSOR

AKX01622

AKX01623 AB

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-1001

THROTTLE POSITION SENSOR CHECK

M1131003200547

.

1. Disconnect the throttle position sensor connector.

2. Measure the resistance between the throttle position sensor 

side connector terminal No. 2 (sensor power supply) and 
terminal No. 4 (sensor ground).

Standard value: 2.0 

− 4.0 kΩ [at 20°C (68°F)]

3. If resistance is outside the standard value, replace the 

throttle body assembly.

ACCELERATOR PEDAL POSITION SENSOR 
CHECK

M1131003400046

.

1. Disconnect the accelerator pedal position sensor connector.
2. Measure the resistance between accelerator pedal position 

sensor connector terminal No. 1 [accelerator pedal position 
sensor (main) earth] and terminal No. 2 [accelerator pedal 
position sensor (main) power supply], and between terminal 
No.7 [accelerator pedal position sensor (sub) earth] and 
terminal No. 8 [accelerator pedal position sensor (sub) 
power supply].

Standard value: 3.5 

− 6.5 kΩ

3. Measure the resistance between accelerator pedal position 

sensor connector terminal No. 2 [accelerator pedal position 
sensor (main) power supply] and terminal No. 3 [accelerator 
pedal position sensor (main) output]; and between terminal 
No.8 [accelerator pedal position sensor (sub) power supply] 
and terminal No. 6 [accelerator pedal position sensor (sub) 
output].

Normal condition:

4. If the measured values are outside the standard value 

range, or if the resistance does not change smoothly, 
replace the accelerator pedal position sensor.

AK201173AE

THROTTLE 
POSITION 
SENSOR

6

1 2 3 4 5

AK201512

THROTTLE POSITION
SENSOR SIDE 
CONNECTOR

AB

When accelerator pedal is 
gently depressed

Changes comparatively 
smoothly in proportion to the 
accelerator pedal depression 
amount.

1 2 3 4 5 6 7 8

AK201309 AB

Equipment side
connector

ACCELERATOR PEDAL
POSITION SENSOR

ACCELERATOR 
PEDAL

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-1002

NOTE: After replacement, adjust the accelerator pedal posi-
tion sensor. (Refer to 

P.13A-994

.)

ACCELERATOR PEDAL POSITION SWITCH 
CHECK

M1131052500056

.

1. Disconnect the accelerator pedal position sensor connector.
2. Check continuity between terminal No. 4 (accelerator pedal 

position switch) and No. 5 (sensor earth) of the connector. 

Normal condition:

3. If defective, replace the accelerator pedal position sensor 

assembly.
NOTE: After replacement, adjust the accelerator pedal posi-
tion sensor. (Refer to 

P.13A-994

.)

HEATED OXYGEN SENSOR CHECK

M1131005000680

Required Special Tools:

• MB991316: Test Harness Set

• MD998464: Test Harness

.

<Left bank heated oxygen sensor (front)>
1. Using scan tool MB991958, observe HO

2

S reading. If 

values are unsatisfactory, or if a scan tool is not available, 
use the following procedure:

(1) Disconnect the heated oxygen sensor connector and 

connect special tool MB991316 to the connector on the 
heated oxygen sensor side.

(2) Make sure that there is continuity [4.5 

− 8.0 ohms at 20°C 

(68

°F)] between terminal No. 1 (red clip of special tool) 

and terminal No. 3 (blue clip of special tool) on the heated 
oxygen sensor connector

(3) If there is no continuity, replace the heated oxygen 

sensor.

(4) Warm up the engine until engine coolant is 80

°C (176°F) 

or higher.

(5) Perform a racing for 5 minutes or more with the engine 

speed of 4,500 r/min.

(6) Connect a digital voltage meter between terminal No. 2 

(black clip) and terminal No. 4 (white clip).

2. While repeatedly revving the engine, measure the heated 

oxygen sensor output voltage.

Standard value:

Accelerator pedal

Continuity

Depressed

No continuity

Released

Continuity (0 k

Ω)

1 2 3 4 5 6 7 8

AK201309 AC

Equipment side
connector

ACCELERATOR PEDAL
POSITION SWITCH

ACCELERATOR 
PEDAL

AKX01624 AB

MB991316

HEATED
OXYGEN
SENSOR
EQUIPMENT
SIDE
CONNECTOR

BLUE

RED

AKX01624

HEATED
OXYGEN
SENSOR
COMPONENT
SIDE
CONNECTOR

MB991316

WHITE

BLACK

AN