Mitsubishi Galant. Manual — part 129

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-197

DTC P0442: Evaporative Emission Control System Leak Detected

TECHNICAL DESCRIPTION

•

To judge if there is leak in the fuel system, PCM
measure the change of the pressure inside the
fuel tank.

•

The PCM turns on the evaporative emission
ventilation solenoid to shot off the evaporative
emission canister outlet port.

AC001943AB

A

B

C

EVAPORATIVE EMISSION
PURGE SOLENOID

EVAPORATIVE
EMISSION CANISTER

EVAPORATIVE
EMISSION
VENTILATION
SOLENOID

FUEL TANK

CHECK VALVE A

CHECK
VALVE B

INTAKE MANIFOLD

SYSTEM DIAGRAM

D

E

F

G

I

H

L

N

M

K

J

O

P

CHAMBER

AC000183AB

EVAPORATIVE EMISSION CANISTER

FUEL TANK

AC000182

EVAPORATIVE EMISSION
PURGE SOLENOID

AB

AC002035AB

EVAPORATIVE EMISSION
VENTILATION SOLENOID

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-198

•

Then the evaporative emission purge solenoid is
driven to set the fuel system into a negative
pressure.

•

When the fuel system develops a vacuum of 2
kPa (0.29 psi), the evaporative emission purge
solenoid is turned "off" and the fuel system
vacuum is maintained at 2 kPa (0.29 psi.)

•

The PCM determines if there is leak in the fuel
system by measuring the change of vacuum
inside the fuel tank.

•

The test is stopped when fuel vapor pressure is
judged as too high.

DTC SET CONDITIONS
Test Conditions

A. At Start up

•

Intake air temperature is 30

°

C (86

°

F) or less

when the engine is started.

•

The engine coolant temperature 30

°

C (86

°

F) or

less when the engine is started.

B. For Test to Run

•

With in 16 minutes after the engine is started.

•

Engine coolant temperature is higher than 60

°

C

(140

°

F.)

•

Engine speed is 1,600 r/min or more.

•

Power steering pressure switch: "OFF"

•

Barometric pressure is above 76 kPa (11 psi.)

•

Volumetric efficiency is between 20 and 80
percent.

•

Vehicle speed is 30 km/h (18.7 mph) or more.

C. For Test to Stop

•

Intake air temperature is less than 5

°

C (41

°

F.)

•

The engine coolant temperature higher than 60

°

C

(140

°

F.)

•

When the evaporative emission purge solenoid
and evaporative emission ventilation solenoid are
closed, the pressure rises within 451 Pa (0.065
psi.)

•

The pressure fluctuation width is less than 647
Pa (0.094 psi.)

•

Fuel tank differential pressure sensor output
voltage is 1 to 4 V.

Judgment Criteria

•

Internal pressure of the fuel tank has changed
more than 785 Pa (0.114 psi) in 20 seconds after
the tank and vapor line were closed.

NOTE: The monitoring time depends on the fuel
level and the temperature in the fuel tank (75

−

125

seconds.)

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 faulty.

•

Fuel tank, purge line or vapor line seal failed.

•

Evaporative emission ventilation solenoid failed.

OVERVIEW OF TROUBLESHOOTING

•

To determine the cause of DTC P0442, a
performance test is needed. The performance
test uses a mechanical vacuum gauge and scan
tool MB991502 set on the fuel tank differential
pressure sensor (TANK PRES SNER 73.) The
mechanical gauge reading is used to verify scan
tool MB991502 reading. A comparison of the
mechanical gauge to scan tool MB991502
determines the problem in the system.

•

Prior to doing the performance test, several
simple inspections are needed to exclude some
possibilities of the symptom.

DIAGNOSIS

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
connecting or disconnecting scan tool MB991502.
In this procedure, scan tool MB991502 should be used in the
metric mode (showing the value in kPa.) If not, set scan tool
MB991502 by selecting the "Syatem Setup" at the main menu.

AC003081 AB

16 PIN

MB991502

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-199

STEP 1. Evaporative Emission System Monitor Test using
scan tool MB991502.

CAUTION

With this monitor, the PCM automatically increases the
engine speed to 1,600 r/min or more. Check that the
transaxle is set to "P."
(1) Turn the ignition switch to the "ON" position.
(2) Erase the DTCs using the scan tool MB991502.
(3) Check that the fuel cap is securely closed. (Tighten until

three clicks are heard.)

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

position.

NOTE: If the engine speed does not reach 2,000 r/min
during the monitor test, adjustment of the Speed Adjusting
Screw may be needed. Refer to

P.13A-438

. and adjust to

the standard value.

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

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

Q: What is displayed on the scan tool MB991507?

"Evap Leak Mon. Completed Test Passed" : The

evaporative emission system is working properly at
this time. Explain to customer that improperly
tightened fuel cap can cause MIL to turn on, and
return the vehicle.

"Evap Leak Mon. Completed. Test Failed and DTCs
Set" : A malfunction has been detected during the monitor

test. Go to Step 2.

"Evap Lead Mon. discontinued. Retest again from the
first" : The monitor was discontinued for a certain reason

(vehicle speed input from computer, engine speed
and engine load deviating from specified range.) Turn
the ignition switch to the "LOCK" (OFF) position once,
and repeat the monitoring from the Step 1.

AC003081 AB

16 PIN

MB991502

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-200

STEP 2. Pressure test for evaporator line from hose B to
hose N.
(1) Remove the module bracket mounting bolts, and

disconnect hose E from the evaporative emission
ventilation solenoid side, and plug the hoses from which the
hoses have been disconnected.

(2) Confirm that the evaporative emission system pressure

pump (Miller number 6872A) is operating properly. Perform
the self-test as described in the manufacturer's instructions.

(3) Connect an evaporative emission system pressure pump to

the fuel filler neck.

(4) Pressure test the system to determine whether any leaks

are present.

NOTE: "Pressure test" in this procedure refers to the I/
M240 Simulation Test (8 simple steps) described in the
evaporative emission system pressure pump (Miller number
6872A) manufacturer's instructions located in the lid of the
pump box.

Q: Are there any leaks in the evaporator line?

YES : Go to Step 4.
NO : Go to Step 3.

AC002028

HOSE E

AC

AC000186