Mitsubishi Montero (2004+). Manual - part 213

 

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Mitsubishi Montero (2004+). Manual - part 213

 

 

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-339

.

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the PCM (ter-
minal No. 116) from the output terminal 
(terminalNo.  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. 
96).

.

TECHNICAL DESCRIPTION

• The output signal of the left bank heated 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 

stays low when air/fuel ratio is forced to be rich. 
The above procedure is repeated when oxygen 
sensor is inactive.

.

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

AK201279

CONNECTOR: C-15

C-15(B)

AD

LEFT BANK
HEATED OXYGEN
SENSOR (REAR)

AK201049

CONNECTOR: D-116

D-116

AC

AK201052

E-112

AB

CONNECTOR: E-112

AK201038AF

CONNECTOR: D-135

PCM

D-135(GR)

AK201049

D-14

AB

CONNECTOR: D-14

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-340

Sensor (The sensor below is determined to be 

normal)

• Volume airflow sensor

• Engine coolant temperature sensor

• Intake air temperature sensor

• Barometric pressure sensor

.

DTC SET CONDITIONS

Logic Flow Chart

START

V

F

 > =4.5V

2secs HAS PASSED

YES

YES

YES

NO

NO

NO

MALFUNCTION

MONITORING

CONDITIONS

YES

NO

MONITORING

CONDITIONS

+5V ON

AK302935

V

F

 < 0.15V

10secs HAS PASSED

YES

YES

NO

NO

END

MALFUNCTION

GOOD

MODULATE A/F CONDITION TO RICH

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-341

Check Conditions

• 3 minutes or more have passed since the engine 

starting sequence was completed.

• Left bank heated oxygen sensor (rear) signal 

voltage has continued to be 0.15 volt or lower.

• Engine coolant temperature is higher than 76°C 

(169

°F).

• Engine speed is higher than 1,200 r/min.

• Volumetric efficiency is higher than 25 percent.

• Volume airflow sensor output frequency is higher 

than 100 Hz.

• At least 20 seconds have passed since fuel shut 

off control was canceled.

• Monitoring time: 10 seconds.

Judgement Criteria

• Making the air/fuel ratio 15 percent for 10 sec-

onds richer does not result in raising the left bank 
heated oxygen sensor (rear) output voltage 
beyond 0.15 volt.

.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function 

− OBD-II Drive Cycle − 

Procedure 6 

− Other Monitor 

P.13A-4

.

.

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

• Left bank heated oxygen sensor (rear) failed.

• Short circuit in left bank heated oxygen sensor 

(rear) output line.

• 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

• MB998464: Test Harness Set

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

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).

• Warming up the engine. When the engine is revved, the 

output voltage should repeat 0 volt and 0.6 to 1.0 volt 
alternately.

(4) 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.00-6

.

NO :  Go to Step 2.

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-342

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

(1) Disconnect the left bank heated oxygen sensor (rear) 

connector C-15 and connect test harness special tool 
MD998464 to the connector on the left bank heated oxygen 
sensor (rear) side.

(2) Warm up the engine until engine coolant temperature 

reaches 80

°C (176°F) or higher.

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

speed of 4,500 r/min.

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

(black clip of special tool) and terminal No. 4 (white clip of 
special tool).

(5) While repeatedly revving the engine, measure the left bank 

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 left bank heated 
oxygen sensor (rear).

• Be careful the heater is broken when voltage of beyond 

8 volts is applied to the left bank heated oxygen sensor 
(rear) heater.
NOTE: If the sufficiently high temperature [of approximate 
400

°

C (752

°

F) or more] is not reached although the left 

bank heated oxygen sensor (rear) is normal, the output volt-
age would be possibly low although the rich air/fuel ratio. 
Therefore, if the output voltage is low, use a jumper wire to 
connect the terminal No. 1 (red clip of special tool) and the 
terminal No. 3 (blue clip of special tool) of the left bank 
heated oxygen sensor (rear) with the positive terminal and 
the negative terminal of 8 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 5.

AK201280

1

2

3

4

CONNECTOR: C-15

C-15(B)

AC

HARNESS 
CONNECTOR: 
COMPONENT SIDE

LEFT BANK
HEATED OXYGEN
SENSOR (REAR)

AKX01624

HEATED
OXYGEN
SENSOR
COMPONENT
SIDE
CONNECTOR

MD998464

WHITE

BLACK

AL

 

 

 

 

 

 

 

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