Mitsubishi Montero (2004+). Manual — part 195

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-267

STEP 11. Check the trouble symptoms.

(1) Carry out a test drive with the drive cycle pattern. Refer to

Diagnostic Function

− OBD-II Drive Cycle − Procedure 6 −

Other Monitor

P.13A-4

.

(2) Check in the diagnostic trouble code (DTC).
Q: Is DTC P0141 set?

YES : Replace the PCM. Then go to Step 12.
NO : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

P.00-6

.

STEP 12. 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 6 −

Other Monitor

P.13A-4

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0141 set?

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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-268

DTC P0150: Heated Oxygen Sensor Circuit (bank 2, sensor 1)

BL

ACK

BL

ACK

BL

ACK

TO PCM

FROM MFI RELAY

WHITE

AK201135

96

108

4

3

1

LEFT BANK
HEATED OXYGEN
SENSOR (FRONT)

POWERTRAIN CONTROL
MODULE (PCM)

11

9

7

2

4

3

1 2

B-26

MU802665

1

12

23 24 25 26

2

13

3

14

4

15

5

16

6

17

7

18

8

19

9

20 21 22

27 28 29 30 31 32 33

10 11

D-116

1
5

7 8

3 4
9 10

2
6

D-14

MU801335

Left Bank Heated Oxygen Sensor (front) Circuit

9192

939495

96979899

100

105

113114

115116117

118119120

106

107108109

110111112

101102103

104

D-135

(MU803805)

AK201277

CONNECTOR: B-26

B-26(GR)

AD

LEFT BANK
HEATED OXYGEN
SENSOR (FRONT)

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-269

.

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the PCM (ter-
minal No. 108) from the output terminal (terminal
No. 4) of the left bank heated oxygen sensor
(front).

• Terminal No. 2 of the left bank heated oxygen

sensor (front) is grounded with or PCM (terminal
No. 96).

.

TECHNICAL DESCRIPTION

• The left bank heated oxygen sensor (front)

detects the concentration of oxygen in the
exhaust gas; it converts that data to voltage, and
sends it to the PCM.

• When the left bank heated oxygen sensor (front)

begins to deteriorate, the heated oxygen sensor
signal response deteriorates also.

• The PCM varies the air/fuel mixture to make it

leaner and richer, and checks the response
speed of the left bank heated oxygen sensor
(front). In addition, the PCM also checks for an
open circuit in the left bank heated oxygen sensor
(front) output line.

.

DESCRIPTIONS OF MONITOR METHODS
Left bank heated oxygen sensor (front) circuit is

switched to 5 volts intentionally when oxygen
sensor output is low, and detects the malfunction
if the output voltage changes to equal or greater
than 4.5 volts. 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

• Misfire monitor

• Fuel system 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

• Accelerator pedal position sensor

.

AK201049

CONNECTOR: D-116

D-116

AC

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-270

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• 3 minutes or more have passed since the engine

starting sequence was completed.

• Left bank heated oxygen sensor (front) signal

voltage has continued to be 0.2 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.

• Monitoring time: 7 seconds.

START

V

F

> =4.5V

2secs HAS PASSED

YES

YES

YES

NO

NO

NO

MALFUNCTION

MONITORING

CONDITIONS

YES

NO

MONITORING

CONDITIONS

+5V ON

AK302930

V

F

< 0.2V

10secs HAS PASSED

YES

YES

NO

NO

END

MALFUNCTION

GOOD

MODULATE A/F CONDITION TO RICH