Mitsubishi Montero (2002-2004). Manual - part 677

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-405

STEP 2. Using scan tool MB991502, check data list item 73: 
Fuel Tank Differential Pressure Sensor.
(1) Turn the ignition switch to the "ON" position.
(2) Remove the fuel cap.
(3) Set scan tool MB991502 to the data reading mode for item 

73, Fuel Tank Differential Pressure Sensor.

• The fuel tank differential pressures should be −3.3 − 3.3 

kPa (

−0.97 − 0.97 in.Hg).

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the fuel tank pressure between 

−3.3 and 3.3 kPa (−

0.97 to 0.97 inHg)?
YES : Go to Step 3.
NO :  Refer to, DTC P0451 - Evaporative Emission System 

Pressure Sensor Range/Performance 

P.13Ac-436

.

STEP 3. Using scan tool MB991502, check actuator test 
item 08: Evaporative Emission Purge Solenoid.
(1) Turn the ignition switch to the "ON" position.
(2) Set scan tool MB991502 to the actuator test mode for item 

08, Evaporative emission purge solenoid.

• An operation sound should be heard and vibration 

should be felt when the evaporative emission purge 
solenoid is operated.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the solenoid operating properly?

YES : Go to Step 4.
NO :  Replace the evaporative emission purge solenoid. 

Then go to Step 5.

STEP 4. Using scan tool MB991502, check actuator test 
item 29: Evaporative Emission Ventilation Solenoid.
(1) Turn the ignition switch to the "ON" position.
(2) Set scan tool MB991502 to the actuator test mode for item 

29, Evaporative emission ventilation solenoid.

• An operation sound should be heard and vibration 

should be felt when the evaporative emission ventilation 
solenoid is operated.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the solenoid operating properly?

YES : Repair or replace the vent hose and air filter. Then go 

to Step 5.

NO :  Replace the evaporative emission ventilation 

solenoid. Then go to Step 5.

ACX01539

16-PIN

MB991502

AC

ACX01539

16-PIN

MB991502

AC

ACX01539

16-PIN

MB991502

AC

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

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STEP 5 Perform the OBD-II drive cycle. 
(1) Carry out a test drive with the drive cycle pattern. (Refer to 

GROUP 13A, Trouble Code Diagnosis 

− OBD-II Drive Cycle 

− Procedure 1 − Evaporative Emission System Leak 

Monitor 

P.13Ab-2

.)

(2) Read the diagnostic trouble code.
Q: Is DTC P0441 set?

YES : Go to Step 1.
NO :  The procedure is complete.

DTC P0442: Evaporative Emission System Leak Detected (Small Leak)

AC203991

SYSTEM DIAGRAM

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

Q

S

R

P

FUEL TANK

CHECK VALVE B

CHECK VALVE A

EVAPORATIVE
EMISSION
PURGE
SOLENOID

EVAPORATIVE EMISSION
VENTILATION SOLENOID

EVAPORATIVE
EMISSION
CANISTER

OVER VENT
VALVE MODULE

VENT PIPE
ASSEMBLY

AB

AC101766

EVAPORATIVE EMISSION CANISTER

AB

AC203904

AC

EVAPORATIVE EMISSION
PURGE SOLENOID

INTAKE AIR DUCT

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-407

.

TECHNICAL DESCRIPTION

• The PCM monitors the Evaporative Emission 

(EVAP) System pressure.

• The PCM controls the evaporative emission ven-

tilation solenoid. It closes the evaporative emis-
sion ventilation solenoid to seal the evaporative 
emission canister side of the system.

• The evaporative emission purge solenoid is 

opened to allow manifold vacuum to create low 
pressure (vacuum) in the EVAP system.

• When the EVAP system develops a vacuum of 2 

kPa (0.29 psi), the evaporative emission purge 
solenoid is closed and the fuel system vacuum is 
maintained at 2 kPa (0.29 psi).

• The PCM determines whether there is a leak in 

the EVAP system by monitoring the vacuum 
inside the fuel tank.

• The test is stopped when fuel vapor pressure 

exceeds predetermined limits.

.

DTC SET CONDITIONS
Remaining fuel amount is 15 

− 40 percent of capac-

ity. (fuel level sensor output voltage is 1.4 

− 2.4 

volts).

Test Conditions:

• Engine coolant temperature is less than 36°C 

(97

°F) when the engine is started.

• Intake air temperature is less than 36°C (97°F) 

when the engine is started.

• Fuel tank temperature is less than 36°C (97°F), 

and with in 800 seconds have elapsed since the 
engine was started.

• Engine coolant temperature is greater than 60°C 

(140

°F).

• Intake air temperature is greater than −10°C 

(14

°F).

• Barometric pressure is greater than 76 kPa (11 

psi).

• Power steering pressure switch: "OFF".

• Fuel tank differential pressure sensor output volt-

age is 1 

− 4 volts.

• Pressure fluctuation is less than 647 Pa (0.094 

psi).

• When the evaporative emission purge solenoid 

and evaporative emission ventilation solenoid are 
closed, the pressure rises in the fuel tank is less 
than 451 Pa (0.065 psi).

• Vehicle speed is greater than or equal to 20 km/h 

(12.4 mph).

• 10 seconds have elapsed from the start of the 

previous monitoring.

• Monitoring time: 75 − 125 seconds.

Judgment Criteria:

• Internal pressure of the fuel tank has changed 

greater than 647 Pa (0.094 psi) in 20 seconds 
after the tank and vapor line were closed.

• Only one monitor during one drive cycle.

.

DTC SET CONDITIONS
Remaining fuel amount is 40 

− 85 percent of capac-

ity. (fuel level sensor output voltage is 2.4 

− 3.7 

volts).

Test Conditions:

• Engine coolant temperature is less than 36°C 

(97

°F) when the engine is started.

• Intake air temperature is less than 36°C (97°F) 

when the engine is started.

• Engine coolant temperature is greater than 20°C 

(68

°F).

• Intake air temperature is greater than −10°C 

(14

°F).

• Fuel tank temperature is less than 36°C (97°F).

• Barometric pressure is greater than 76 kPa (11 

psi).

• Fuel tank differential pressure sensor output volt-

age is 1 

− 4 volts.

• When the evaporative emission purge solenoid 

and evaporative emission ventilation solenoid are 
closed, the pressure rises in the fuel tank is less 
than 324 Pa (0.047 psi).

• 10 seconds have elapsed from the start of the 

previous monitoring

• Monitoring time: 10 − 14 minutes.

AC101763 AB

REAR COIL SPRING (RH)

EVAPORATIVE EMISSION VENTILATION 
SOLENOID

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DIAGNOSTIC TROUBLE CODE PROCEDURES

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Judgment Criteria:

• Internal pressure of the fuel tank has changed 

greater than 1.9 kPa (0.28 psi) in 128 seconds 
after the tank and vapor line were closed.

• Only one monitor during one drive cycle.

.

TROUBLESHOOTING HINTS (The most likely 
causes for this code to be set are:)

• Loose fuel cap.

• Fuel cap relief pressure is incorrect.

• Evaporative emission canister seal is leaking.

• Fuel tank, purge line or vapor line seal is leaking.

• Evaporative emission ventilation solenoid does 

not seal.

.

OVERVIEW OF TROUBLESHOOTING

• To determine the cause of DTC P0442, a perfor-

mance test is needed. The performance test uses 
a mechanical vacuum gauge and scan tool 
MB991502 set to the data reading mode for the 
fuel tank differential pressure sensor (TANK 
PRES SNER 73). The mechanical gauge reading 
is used to verify the scan tool reading. A compari-
son of the mechanical gauge and scan tool 
MB991502 determines whether there is problem 
in the system.

• Prior to doing the performance test, ensure that 

the fuel cap is closed securely. Inspect all EVAP 
system hoses and tubes for damage.