Mitsubishi Montero (2002-2004). Manual — part 563

TROUBLE CODE DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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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 Tool:

• MB991502: Scan Tool (MUT-II)

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
NOTE: When mode II is selected with MUT-II, the Malfunction
Indicator Lamp (SERVICE ENGINE SOON or Check Engine
Lamp) 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 com-
ponent electrical faults (opens/shorts), the time for the diagnos-
tic 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 MUT-II. 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 MB991502 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).

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 heater
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

ACX01539

16-PIN

MB991502

AC

TROUBLE CODE DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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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 MB991502 from the data link

connector.

INSPECTION USING SCAN TOOL MB991502,
DATA LIST AND ACTUATOR TESTING

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Carry out inspection by means of the data list and the

actuator test function. If there is an abnormality, check and
repair the chassis harnesses and components. Refer to
Data List Reference Table

P.13Ab-29

.

Refer to Actuator Test Reference Table

P.13Ab-42

.

4. Re-check using scan tool MB991502 and check to be sure

that the abnormal input and output have returned to normal
because of the repairs.

5. Erase the diagnostic trouble code(s).
6. Turn the ignition switch to the "LOCK" (OFF) position.
7. Disconnect scan tool MB991502 from the data link

connector.

8. Start the engine again and do a test drive to confirm that the

problem is eliminated.

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 121 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 MUT-II (MB991502) 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 121 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" date. 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.

ACX01539

16-PIN

MB991502

AC

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OBD- II DRIVE CYCLE

All kinds of diagnostic trouble codes (DTCs) can be monitored by carrying out a short drive according to the
following six drive cycle pattern. In other words, doing such a drive regenerates any kind of trouble which
involves illuminating the Malfunction Indicator Lamp (SERVICE ENGINE SOON or Check Engine Lamp) and
verifies the repair procedure has eliminated [the trouble the Malfunction Indicator Lamp (SERVICE ENGINE
SOON or Check Engine Lamp) is no longer illuminated].

CAUTION

Two technicians should always be in the vehicle when carrying out a test.
NOTE: Check that the diagnosis trouble code (DTC) is not output before traveling in the drive cycle pattern.
Erase the DTC if it has been output.

DATA

UNIT

Engine coolant temperature

°C or °F

Engine speed

r/min

Vehicle speed

km/h or mph

Long-term fuel trim (long-term fuel trim)

%

Short-term fuel trim (short-term fuel trim)

%

Fuel system status

• Open loop

• Closed loop

• Open loop-drive condition

• Open loop-DTC set

• Closed loop-O

2

(rear) failed

Calculated load value

%

Diagnostic trouble code during data recording

-

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DRIVE CYCLE PATTERN LIST

.

PROCEDURE MONITOR ITEM

DIAGNOSTIC TROUBLE
CODE (DTC)

1

Evaporative emission system leak monitor

P0441, P0442, P0451,
P0452, P0453, P0455,
P0456

2

Fuel trim monitor

P0171, P0172, P0174,
P0175

3

Catalytic converter monitor

P0421, P0431

4

Heated oxygen sensor monitor

P0133, P0139, P0153,
P0159

5

Exhaust gas recirculation (EGR) system monitor

P0401

6

Other monitor

Main components

P0134, P0154, P0300,
P0301, P0302, P0303,
P0304, P0305, P0306,
P0506, P0507, P1400

Sensors and switches

P0101, P0102, P0106, P107,
P0108, P0111, P0112,
P0113, P0116, P0117,
P0118, P0125, P0181,
P0182, P0183, P0335,
P0340, P0461

Wire breakage and short
circuit

P0130, P0131, P0132,
P0135, P0136, P0137,
P0138, P0141, P0150,
P0151, P0152, P0155,
P0156, P0157, P0158,
P0161, P0201, P0202,
P0203, P0204, P0205,
P0206, P0403, P0443,
P0446