Mitsubishi Montero (2002-2004). Manual — part 700

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-497

STEP 24. Check for clogging in the evaporative emission
canister.
(1) Remove the evaporative emission canister. (Refer to

GROUP 17, Evaporative Emission Canister and Fuel Tank
Pressure Relief Valve

P.17-66

).

(2) Connect a hand vacuum pump to the vent nipple of the

evaporative emission canister.

(3) Plug the other two nipples or loop a hose between the other

nipples.

(4) Apply a pressure on the vacuum pump.
(5) When each nipple is unplugged, air should pass through the

unplugged nipple.

Q: Is the evaporative emission canister in good condition?

YES : Reinstall the evaporative emission canister. (Refer to

GROUP 17, Evaporative Emission Canister and Fuel
Tank Pressure Relief Valve

P.17-66

). Go to Step 25 .

NO : Replace the evaporative emission canister. (Refer to

GROUP 17, Evaporative Emission Canister and Fuel
Tank Pressure Relief Valve

P.17-66

). Go to Step 26 .

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-498

STEP 25. Using scan tool MB991502, check evaporative
emission system monitor test.

CAUTION

• To prevent damage to scan tool MB991502, always turn

the ignition switch to the "LOCK" (OFF) position before
connecting or disconnecting scan tool MB991502.

• During this test, the PCM automatically increases the

engine speed to 1,600 r/min or greater. Check that the
transmission is set to "P" position.

(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Erase the DTCs using scan tool MB991502. (Refer to

GROUP 13A, Trouble Code Diagnosis

P.13Ab-2

).

(4) Check that the fuel cap is securely closed. (Tighten until

three clicks are heard).

(5) Start the engine.
(6) Select "System Test" and press the "YES" key.
(7) Select "Evap Leak Mon" and press the "YES" key.
(8) During this test, keep the accelerator pedal at the idling

position.

(9) Keep the engine speed and engine load within the specified

range. When the monitor test starts, the "In Progress" item
on scan tool MB991502 will change from "NO" to "YES".

(10)Turn the ignition switch to the "LOCK" (OFF) position and

disconnect scan tool MB991502.

Q: What is displayed on scan tool MB991502?

"Evap Leak Mon. Completed. Test Passed" : The

evaporative emission system is working properly at
this time. Go to Step 26 .

"Evap Leak Mon. Completed. Test Failed and DTCs Set"
:

Replace the PCM. Go to Step 26.

"Evap Lead Mon. discontinued. Retest again from the
first" : The monitor test was interrupted. Turn the ignition

switch to the "LOCK" (OFF) position once and repeat
evaporative emission system monitor test.

STEP 26. Perform the OBD-II drive cycle.
(1) Confirm the repair by performing the appropriate drive

cycle. [Refer to GROUP 13A, Trouble Code Diagnosis

−

OBD-II Drive Cycle (Procedure 1: Evaporative Emission
Control system Leak Monitor)

P.13Ab-2

].

(2) Read the DTC.
Q: Is DTC P0455 set?

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

ACX01539

16-PIN

MB991502

AC

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-499

DTC P0456: Evaporative Emission System Leak Detected (Very 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

AC101763 AB

REAR COIL SPRING (RH)

EVAPORATIVE EMISSION VENTILATION
SOLENOID

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-500

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

Test Conditions:

• Fuel level sensor output voltage is 2.4 − 3.7 volts

when the engine is started, and the amount of
remaining fuel is 40

− 85 percent of capacity.

• 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 33°C (91°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 seconds.

Judgment Criteria:

• Internal pressure of the fuel tank has changed

greater than 1,177

− 1,373 Pa (0.171 − 0.199 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 P0456, 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.