Mitsubishi Montero (2002-2004). Manual — part 850

EMISSION CONTROL

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ENGINE AND EMISSION CONTROL

17-63

ENGINE COOLANT TEMPERATURE SENSOR
CHECK

M1173008100426

To inspect these parts, refer to GROUP 13A, Multiport Fuel
Injection (MFI) Diagnosis

− Diagnostic Trouble Code chart

P.13Ab-22

.

INTAKE AIR TEMPERATURE SENSOR CHECK

M1173008200218

To inspect these parts, refer to GROUP 13A, Multiport Fuel
Injection (MFI) Diagnosis

− Diagnostic Trouble Code Chart

P.13Ab-22

.

FUEL TANK DIFFERENTIAL PRESSURE SENSOR
CHECK

M1173007700027

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

− Fuel

tank inspection

P.13B-10

.

EVAPORATIVE EMISSION VENTILATION
SOLENOID CHECK

M1173007800080

Refer to GROUP 17, Evaporative emission canister and fuel
tank pressure relief valve

− Fuel tank pressure relief valve

inspection

P.17-69

.

EXHAUST GAS RECIRCULATION (EGR) SYSTEM

GENERAL DESCRIPTION (EGR SYSTEM)

M1173005200189

The exhaust gas recirculation (EGR) system lowers
the nitrogen oxide (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.
The powertrain control module monitors the EGR
system and illuminates the check engine/malfunction
indicator lamp to indicate that there is a malfunction.

EMISSION CONTROL

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ENGINE AND EMISSION CONTROL

17-64

SYSTEM DIAGRAM

COMPONENT LOCATION

M1173007600138

EGR VALVE (STEPPER MOTOR) CHECK

M1173050200026

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 circuit is normal, either the stepper motor or the
engine A/T-ECU may have failed.

AK200803

VOLUME AIRFLOW
SENSOR

ENGINE COOLANT
TEMPERATURE SENSOR

CRANKSHAFT POSITION
SENSOR

PCM

MFI RELAY

BATTERY

EGR
VALVE

AB

AK200803

AC203907

AC

EGR VALVE

EMISSION CONTROL

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ENGINE AND EMISSION CONTROL

17-65

.

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 i 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.
4. Connect terminal 1 or terminal 3 to the negative (

−) terminal

of the battery to test the presence of vibrations that result
from the operation of the stepper motor (by feeling it’s slight
vibrations.

5. Connect the positive (+) terminal the battery to terminal 5.
6. Connect terminal 4 or terminal 6 to the negative (

−) terminal

of the battery to test the presence of vibrations that result
from the operation of the stepper motor (by feeling it’s slight
vibrations.

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: If 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.

VOLUME AIRFLOW SENSOR CHECK

M1173007900441

To inspect these parts, refer to GROUP 13A, Multiport Fuel
Injection (MFI) Diagnosis

− Diagnostic Trouble Code Chart

P.13Ab-22

.

AK200805

1 2 3
4 5 6

1 2 3
4 5 6

AB

AK200806

1 2 3

4 5 6

EGR VALVE

AB

AK200806

+

-

AK200807

BATTERY

MB991658

AB

+

-

AK200807

EMISSION CONTROL

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ENGINE AND EMISSION CONTROL

17-66

ENGINE COOLANT TEMPERATURE SENSOR
CHECK

M1173008100437

To inspect these parts, refer to GROUP 13A, Multiport Fuel
Injection (MFI) Diagnosis

− Diagnostic Trouble Code Chart

P.13Ab-22

.

CRANKSHAFT POSITION SENSOR CHECK

M1173008300226

To inspect these parts, refer to GROUP 13A, Multiport Fuel
Injection (MFI) Diagnosis

− Diagnostic Trouble Code Chart

P.13Ab-22

.

EVAPORATIVE EMISSION CANISTER AND FUEL TANK PRESSURE RELIEF
VALVE

REMOVAL AND INSTALLATION

M1173004800252

<EVAPORATIVE EMISSION VENTILATION SOLENOID, ONBOAD REFUELING VAPOR
RECOVERY(ORVR) VENT VALVE MODULE>

AC204036AB

1

13

12

11

10

9

8

7

6

5

4

3

2