Mitsubishi Montero Sport (2004+). Manual - part 236

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-357

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the PCM (ter-
minal No. 73) from the output terminal (terminal 
No. 4) of the left bank heated oxygen sensor 
(rear).

• Terminal No. 2 of the left bank heated oxygen 

sensor (rear) is grounded with PCM (terminal No. 
57).

.

TECHNICAL DESCRIPTION

• The output signal of the heated left bank oxygen 

sensor (front) is compensated by the output sig-
nal of the left bank heated oxygen sensor (rear).

• The PCM checks for an open circuit in the left 

bank heated oxygen sensor (rear) output line.

.

DESCRIPTIONS OF MONITOR METHODS
Left bank heated oxygen sensor (rear) output voltage 

does not change during specified go/stop opera-
tions including fuel cut are repeated.

.

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)

• Heated oxygen sensor heater (front) monitor

• Heated oxygen sensor heater (rear) monitor

• Air/fuel ratio feedback monitor

Sensor (The sensor below is determined to be 

normal)

• Volume airflow sensor

• Engine coolant temperature sensor

• Intake air temperature sensor

• Barometric pressure sensor

.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-358

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• Engine coolant temperature is higher than 76°C 

(169

°F).

• The left bank heated oxygen sensor (front) is 

active.

• The cumulative volume airflow sensor output fre-

quency is higher than 4,000 Hz.

• Repeat 3 or more times: drive

*1

, stop

*2

.

Drive

*1

: 

• Engine speed is higher than 1,500 r/min.

• Volumetric efficiency is higher than 40 per-

cent.

• Vehicle speed is higher than 30 km/h (18.7 

mph).

• A total of more than 10 seconds have 

elapsed with the above mentioned condi-
tions, and more than 2 seconds have 
elapsed with the fuel shut off.

Stop

*2

:

•  Vehicle speed is lower than 1.5 km/h (0.9 

mph).

Judgement Criteria

• Change in the output voltage of the left bank 

heated oxygen sensor (rear) is lower than 0.313 
volt.
NOTE: Monitoring stops after fuel has been shut 
off for more than 38 seconds.

.

END

YES

NO

NO

NO

START

MONITORING

CONDITION

YES

MALFUNCTION

GOOD

F1: COUNTER OF A DRIVING STATE.
F2: COUNTER OF A STOP STATE.

OUTPUT VOLTAGE 

CHANGE < 0.313 V

GO/STOP OPERATION

FOR SPECIFIED TIMES

YES

AK301442

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-359

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function 

− OBD-II Drive Cycle − 

Procedure 4 

− Heated Oxygen Sensor Monitor 

P.13A-4

.

.

TROUBLESHOOTING HINTS (The most likely 
causes for this code to be set are:)

• Left bank heated oxygen sensor (rear) failed.

• Connector damage.

• PCM failed. 

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I

• MB991827: USB Cable

• MB991911: Main Harness B

• MD998464: Test Harness

STEP 1. Using scan tool MB991958, check data list item 59: 
Heated Oxygen Sensor Bank 2, Sensor 2 (left rear).

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 

59, Heated Oxygen Sensor Bank 2, Sensor 2 (left rear).

(4) Warm up the engine.

• After increasing the output voltage 0.15 volt or more by 

the engine revving, finish it. Then confirm that the output 
voltage reduces to 0.15 volt or less within 3 seconds.

(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 :  Replace the heated oxygen sensor (rear). Then go to 

Step 2. 

AK303629AB

MB991911

MB991827

MB991824 

16-PIN

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-360

STEP 2. Check the left bank heated oxygen sensor (rear).
(1) Disconnect the left bank heated oxygen sensor (rear) 

connector E-48 and connect test harness special tool, 
MD998464, to the connector on the left bank heated oxygen 
sensor (front) side.

(2) Warm up the engine until engine coolant 80

°C (176°F) or 

higher.

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

speed of 4,500 r/min.

(4) Connect a digital volt meter between terminal No. 2 (black 

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

(5) While repeatedly revving the engine, measure the heated 

oxygen sensor (rear) output voltage.

Standard value: 0.6 

− 1.0 volt

CAUTION

• Be very careful when connecting the jumper wire; 

incorrect connection can damage the oxygen sensor.

• Be careful the heater is broken when voltage of beyond 

12 volts is applied to the oxygen sensor heater.
NOTE: If the sufficiently high temperature (of approximate 
400

°

C or more) is not reached although the oxygen sensor 

is normal, the output voltage would be possibly low 
although the rich air-fuel ratio. Therefore, if the output volt-
age is low, use a jumper wire to connect the terminal No.2 
and the terminal No. 1 of the oxygen sensor with a (+) termi-
nal and (-) terminal of 12 volts power supply respectively, 
then check again.

Q: Is the voltage between 0.6 and 1.0 volt?

YES : Go to Step 3.
NO :  Replace the left bank heated oxygen sensor (rear). 

Then go to Step 4.

AK200498

1

2

3

4

E-48(B)

AB

CONNECTOR: E-48

HARNESS 
CONNECTOR: 
COMPONENT SIDE

LEFT BANK
HEATED OXYGEN
SENSOR (REAR)

AKX01624

HEATED
OXYGEN
SENSOR
COMPONENT
SIDE
CONNECTOR

MD998464

WHITE

BLACK

AL