Mitsubishi Montero (2004+). Manual — part 131

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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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. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System select."
5. Choose "MFI" from the "POWER TRAIN" tab.
6. Select "MITSUBISHI."
7. Select "Actuator Test."
8. Choose an appropriate item and select the "OK" button.

PROVISIONAL DTCs [MUT-III OBD-II Test Mode -
Results (Mode 7)]

The scan tool MB991958 (MUT-III Sub Assembly) will display
the Provisional DTCs reported by PCM if the PCM detects
some malfunction for "Misfire", "Fuel System" and "Compre-
hensive" monitoring during a SINGLE Driving Cycle. The
intended use of this data is to assist the technician after a vehi-
cle repair, and after clearing diagnostic information, by report-
ing test result after a SINGLE Driving Cycle. Note that the test
results reported by this mode do not necessarily indicate a
faulty component/system. If test results indicate a failure after
ADDITIONAL (consecutive) driving, then the Malfunction Indi-
cator Lamp (SERVICE ENGINE SOON) will be illuminated and
a DTC will set.

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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MODE 6 REFERENCE TABLE

The engine control module (ECM) monitors the condition of emission control system.
By selecting MODE 6 using scan tool, Test Result and Limit Value (minimum) *1 or (maximum) *2 about the
main items of emission control system which ECM monitors can be confirmed. The value at the last monitor-
ing is output by ECM as a test result.

TEST
ID

MONITORING
ITEM

SIMPLE TECHNICAL
DESCRIPTION

INDICATION OF SCAN
TOOL

CONVERSION
COEFFICIENT IN
USING
GENERAL SCAN
TOOL

01

Catalyst
monitor (Bank
1)

PCM monitors the deterioration of
catalyst at right bank side by the
output frequency ratio between
right bank heated oxygen sensor
(front) and right bank heated
oxygen sensor (rear).

Catalyst Frequency
Ratio Bank 1
Test Result and Limit
Value (max.)

× 0.0039

02

Catalyst
monitor (Bank
2)

PCM monitors the deterioration of
catalyst at left bank side by the
output frequency ratio between left
bank heated oxygen sensor (front)
and left bank heated oxygen sensor
(rear).

Catalyst Frequency
Ratio Bank 2
Test Result and Limit
Value (max.)

× 0.0039

03

EGR monitor

PCM monitors the operation of
EGR system by the pressure
difference of intake manifold
between before and after
introduction of EGR using the
manifold absolute pressure sensor.

EGR Monitor Pressure
Value
Test Result and Limit
Value (min.) kPa

× 0.43 kPa

06

Evaporation
leak monitor
(Small leak)

After PCM vacuumizes the fuel tank
and the fuel line and then the
specified time is passed, PCM
monitors the leak of fuel
evaporation gas through the fuel
tank differential pressure sensor to
check the reduction of vacuum in
the fuel tank.

EVAP Leak Mon. 1 mm
Pressure Value
Test Result and Limit
Value (max.) kPa

× 0.032 kPa

07

Evaporation
leak monitor
(Gross leak)

PCM monitors the leak of fuel
evaporation gas by checking
whether the pressure can be
reduced (the amount of pressure
reduction) using the fuel tank
differential pressure sensor after
sealing the fuel tank and the fuel
line.

EVAP Leak Mon. Gross
Pressure Value
Test Result and Limit
Value (min.) kPa

× 0.032 kPa

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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NOTE: *1 : Minimum value: The test fails if test value is less than this value.
NOTE: *2 : Maximum value: The test fails if test value is greater than this value.

DIAGNOSTIC BY DIAGNOSTIC TEST MODE II
(INCREASED SENSITIVITY)

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

08

Evaporation
leak monitor
(Very small
leak)

After PCM vacuumizes the fuel tank
and the fuel line and then the
specified time is passed, PCM
monitors the leak of fuel
evaporation gas through the fuel
tank differential pressure sensor to
check the reduction of vacuum in
the fuel tank.

EVAP Leak Mon. 0.5
mm Pressure Value
Test Result and Limit
Value (max.) kPa

× 0.032 kPa

09

Heated oxygen
sensor monitor
(Rich/Lean
Switching)
(Bank 1 Sensor
1)

PCM monitors the deteriorated
condition of the heated oxygen
sensor by checking the lean/rich
switching frequency of the heated
oxygen sensor.

HO2S B1 SENSOR 1
Rich/Lean Switching
Count
Test Result and Limit
Value (min.)

×1 count

0A

Heated oxygen
sensor monitor
(Rich/Lean
Switching)
(Bank 2 Sensor
1)

PCM monitors the deteriorated
condition of the heated oxygen
sensor by checking the lean/rich
switching frequency of the heated
oxygen sensor.

HO2S B2 SENSOR 1
Rich/Lean Switching
Count
Test Result and Limit
Value (min.)

× 1count

0B

Heated oxygen
sensor monitor
(Voltage) (Bank
1 Sensor 2)

PCM checks the output voltage of
the heated oxygen sensor (rear) in
order to monitor whether the heated
oxygen sensor output is stuck.

HO2S B1 SENSOR2
Change in Volt
Test Result and Limit
Value (min.)

× 19.5mV

0C

Heated oxygen
sensor monitor
(Voltage) (Bank
2 Sensor 2)

PCM checks the output voltage of
the heated oxygen sensor (rear) in
order to monitor whether the heated
oxygen sensor output is stuck.

HO2S B2 SENSOR 2
Change in Volt
Test Result and Limit
Value (min.)

× 19.5mV

TEST
ID

MONITORING
ITEM

SIMPLE TECHNICAL
DESCRIPTION

INDICATION OF SCAN
TOOL

CONVERSION
COEFFICIENT IN
USING
GENERAL SCAN
TOOL

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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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.
NOTE: When mode II is selected with MB991958, the Malfunc-
tion Indicator Lamp (SERVICE ENGINE SOON) will light when
the powertrain control module (PCM) first detects the trouble
(Note that this is only for emission-related trouble). At the same
time, the relevant diagnostic trouble codes will be registered. In
respect to the comprehensive component electrical faults
(opens/shorts), the time for the diagnostic trouble code to be
registered after the fault occurrence is four seconds

→

one

second. Therefore, the confirmation of the trouble symptom
and the confirmation after completing repairs can be reduced.
To return to the normal mode I after mode II has been selected
once, the ignition switch must be turned "OFF" once or mode I
must be reselected with MB991958. The diagnostic trouble
code, system readiness test status and freeze frame data, etc.,
will be erased when mode I is returned to, so record these
before returning to mode I.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Change the diagnostic test mode of the powertrain control

module to DIAGNOSTIC TEST MODE II (INCREASED
SENSITIVITY).

4. Road test the vehicle.
5. Read the diagnostic trouble code and repair the

malfunctioning part.

6. Turn the ignition switch to the "LOCK" (OFF) position.
7. Disconnect scan tool MB991958 from the data link

connector.

ON-BOARD DIAGNOSTICS

The powertrain control module (PCM) monitors the input/output signals (some signals all the time and others
under specified conditions) of the PCM. When a malfunction continues for a specified time or longer after the
irregular signal is initially monitored, the PCM judges that a malfunction has occurred. After the PCM first
detects a malfunction, a diagnostic trouble code is recorded when the engine is restarted and the same mal-
function is re-detected. However, for items marked with a "*", a diagnostic trouble code is recorded on the first
detection of the malfunction. There are 130 diagnostic items. The diagnostic results can be read out with a
scan tool. Since memorization of the diagnostic trouble codes is backed up directly by the battery, the diag-
nostic results are memorized even if the ignition key is turned off. The diagnostic trouble codes will, however,
be erased when the battery terminal or the PCM connector is disconnected. In addition, the diagnostic trouble
code can also be erased by turning the ignition switch to ON and sending the diagnostic trouble code erase
signal from scan tool MB991958 to the PCM.
NOTE: If the sensor connector is disconnected with the ignition switch turned on, the diagnostic trouble code
is memorized. In this case, send the diagnostic trouble code erase signal to the PCM in order to erase the
diagnostic memory. The 130 diagnostic items are all indicated sequentially from the smallest code number.
The PCM records the engine operating condition when the diagnostic trouble code is set. This data is called
"Freeze-frame" data. This data can be read by using the scan tool, and can then be used in simulation tests
for troubleshooting. Data items are as follows:
NOTE: As for Diagnostic trouble code P1603, "freeze frame" data is not memorized.

AK302970

AB

MB991911

MB991824

MB991827