Mitsubishi Montero (2004+). Manual — part 415

EMISSION CONTROL

TSB Revision

ENGINE AND EMISSION CONTROL

17-67

5. If the purge flow volume is less than the standard value,

check it again with the vacuum hose disconnected from the
EVAP canister. If the purge flow volume is less than the
standard value, check the vacuum port and the vacuum
hose for clogging. Also check the EVAP purge solenoid. If
the purge flow volume is at the standard value, replace the
EVAP canister.

EVAPORATIVE EMISSION PURGE SOLENOID
CHECK

M1173001700223

1. Disconnect the vacuum hose (black, black with red paint

mark) from the evaporative emission (EVAP) purge solenoid
valve.
NOTE: When disconnecting the vacuum hose, always place
an identification mark so that it can be reconnected at its
original position.

2. Disconnect the harness connector.
3. Connect a hand vacuum pump to nipple (B) of the EVAP

purge solenoid valve (refer to the illustration at left).

4. As described in the chart below, check airtightness by

applying a vacuum with voltage applied directly from the
battery to the EVAP purge solenoid valve and without
applying voltage.

5. Measure the resistance between the terminals of the EVAP

purge solenoid valve.

Standard value: 30

− 34 Ω [at 20°C (68°F)]

6. Replace the solenoid if resistance is out of specification.

VOLUME AIRFLOW SENSOR CHECK

M1173007900515

To inspect the sensor, refer to GROUP 13A, Multiport Fuel
Injection (MFI)

− Multiport Fuel Injection (MFI) Diagnosis −

Diagnostic Trouble Code Chart

P.13A-26

.

BAROMETRIC PRESSURE SENSOR CHECK

M1173008000300

To inspect the sensor, refer to GROUP 13A, Multiport Fuel
Injection (MFI)

− Multiport Fuel Injection (MFI) Diagnosis −

Diagnostic Trouble Code Chart

P.13A-26

.

BATTERY POSITIVE
VOLTAGE

NORMAL CONDITION

Applied

Vacuum leaks

Not applied

Vacuum maintained

AKX00341

A

B

AKX00341AC

AKX00342

EMISSION CONTROL

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ENGINE AND EMISSION CONTROL

17-68

ENGINE COOLANT TEMPERATURE SENSOR
CHECK

M1173008100590

To inspect the sensor, refer to GROUP 13A, Multiport Fuel
Injection (MFI)

− Multiport Fuel Injection (MFI) Diagnosis −

Diagnostic Trouble Code Chart

P.13A-26

.

INTAKE AIR TEMPERATURE SENSOR CHECK

M1173008200304

To inspect the sensor, refer to GROUP 13A, Multiport Fuel
Injection (MFI)

− Multiport Fuel Injection (MFI) Diagnosis −

Diagnostic Trouble Code Chart

P.13A-26

.

FUEL TANK DIFFERENTIAL PRESSURE SENSOR
CHECK

M1173007700210

To inspect the sensor, refer to GROUP 13B, Fuel Supply

−

On-vehicle Service

− Fuel Tank Differential Presure Sensor

Check

P.13B-7

.

EVAPORATIVE EMISSION VENTILATION
SOLENOID CHECK

M1173007800187

Refer to Emission Control

− Evaporative Emission Canister and

Fuel Tank Pressure Relief Valve

− Inspection − Evaporative

Emission Ventilation Solenoid Check

P.17-75

.

EXHAUST GAS RECIRCULATION (EGR) SYSTEM

GENERAL DESCRIPTION (EXHAUST GAS RECIRCULATION SYSTEM)

M1173005200316

The exhaust gas recirculation (EGR) system lowers
the nitrogen oxides (NOx) emission level. When the
air/fuel mixture combustion temperature is high, a
large quantity of NOx is generated in the combustion
chamber. Therefore, this system recirculates part of
exhaust gas from the exhaust port of the cylinder
head to the combustion chamber through the intake
manifold to decrease the air/fuel mixture combustion
temperature, resulting in reduction of NOx. The EGR
flow rate is controlled by the EGR valve (Stepper
Motor) so as not to decrease the driveability.

OPERATION

When the engine coolant temperature is low, when
the engine is at idle or when a wide open throttle
operation is performed, the EGR valve (Stepper
Motor) is kept closed, achieving no EGR. After warm-
ing up of the engine, the EGR valve (Stepper Motor)
can be opened by the powertrain control module
(PCM).
The PCM monitors the EGR system and illuminates
the check engine/malfunction indicator lamp to indi-
cate that there is a malfunction.

EMISSION CONTROL

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ENGINE AND EMISSION CONTROL

17-69

SYSTEM DIAGRAM

COMPONENT LOCATION

M1173007600138

EGR VALVE (STEPPER MOTOR) CHECK

M1173050200082

Required Special Tool:
MB991658: Test Harness Set

.

Checking the Operation Sound
1. Check that the operation sound of the stepper motor can be

heard from the EGR valve when the ignition switch is turned
ON (without starting the engine).

2. If the operation sound cannot be heard, inspect the drive

circuit of the stepper motor.

NOTE: If the operation sound is not heard, and the circuit is
normal, either the stepper motor or the PCM may have failed.

.

AK301592

VOLUME AIRFLOW
SENSOR

ENGINE COOLANT
TEMPERATURE SENSOR

CRANKSHAFT POSITION
SENSOR

PCM

MFI RELAY

BATTERY

EGR
VALVE

AB

AC203907

AC

EGR VALVE

EMISSION CONTROL

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ENGINE AND EMISSION CONTROL

17-70

Checking the Coil Resistance
1. Remove the EGR valve.
2. Measure the resistance between terminal 2 and either

terminal 1 or terminal 3 of the connector at the EGR valve.

Standard value: 10

− 20 Ω [at 20°C (68°F)]

3. If the resistance is not within the standards, replace the EGR

valve.

4. Measure the resistance between terminal 5 and either

terminal 6 or terminal 4 of the connector at the EGR valve.

Standard value: 10

− 20 Ω [at 20°C (68°F)]

5. If the resistance is not within the standards, replace the EGR

valve.

.

Operation Check
1. Remove the EGR valve.
2. Connect special tool MB991658 to the EGR valve.

3. Connect the positive (+) terminal the battery to terminal 2.

CAUTION

Connecting battery voltage to the EGR valve for a long
term could damage the coil.
4. Connect terminals 1 and 3 to the negative (-) terminal of the

battery, in order to test whether the stepper motor vibrates
(with a slight shudder), indicating that the stepper motor is
operating.

5. Connect the positive (+) terminal the battery to terminal 5.

CAUTION

Connecting battery voltage to the EGR valve for a long
term could damage the coil.
6. Connect terminals 4 and 6 to the negative (-) terminal of the

battery, in order to test whether the stepper motor vibrates
(with a slight shudder), indicating that the stepper motor is
operating.

7. If vibrations can be felt as a result of the test, the stepper

motor is determined to be normal.

EGR VALVE (STEPPER MOTOR) CLEANING

M1173050300012

NOTE: DO not use solvents or other cleaning agents, which will
enter the motor and cause a malfunction.
Remove the EGR valve and make sure that it is not stuck and
does not have any carbon deposits. If there are any carbon
deposits, use a wire brush to clean it.

AK200805

1 2 3
4 5 6

1 2 3
4 5 6

AB

AK200806

1 2 3

4 5 6

EGR VALVE

AC

AK200806

+

-

AK200807

BATTERY

MB991658

AC

+

-

AK200807