Mitsubishi Galant. Manual — part 274

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-321

•

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 or clog 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 is 30

°

C (86

°

F) or

less when the engine is started.

Test Conditions 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 25 and 80
percent.

•

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

Test Conditions C: For Test to Stop

•

Intake air temperature is less than 5

°

C (41

°

F.)

•

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

•

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

•

Fuel tank differential pressure sensor output
voltage 1

−

4 V.

Judgment Criteria

•

The fluctuation of fuel tank internal pressure is
less than 324 Pa (0.047 psi) in 20 seconds after
the evaporative emission purge solenoid had
been driven when the fuel tank and vapor line
were closed.

NOTE: The monitoring time (75

−

125 seconds.)

depends on the fuel level and the temperature in the
fuel tank.

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

•

Loose fuel cap.

•

Fuel cap relief pressure is incorrect.

•

Fuel overflow limiter valve failed.

•

Purge line or vapor line is clogged.

•

Fuel tank, purge line or vapor line seal failed.

•

Evaporative emission purge solenoid failed.

•

Evaporative emission ventilation solenoid failed.

•

Fuel tank differential pressure sensor failed.

•

Evaporative emission canister seal is faulty.

•

Evaporative emission canister is clogged.

OVERVIEW OF TROUBLESHOOTING

•

To determine the cause of DTC P0455, 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 reading to the scan tool
MB991502 reading determines the reading
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)

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-322

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 "System Setup" at the main menu.

STEP 1. Check for leaks in the evaporator line hose A,
hose B and evaporative emission purge solenoid valve.
(1) Disconnect hose A at the intake manifold side, and then

connect a hand vacuum pump to the hose.

(2) Apply vacuum.

NOTE: The vacuum should be 40 kPa (5.8 psi) or less.

Q: Is the vacuum maintained?

YES : Go to Step 4.
NO : Go to Step 2.

STEP 2. Check for leaks in the evaporator line hose A and
hose B.
(1) The leakage test with a hand vacuum pump on hose A.

Q: Are there any leaks?

YES : Replace that hose. Then go to Step 32.
NO : Go to Step 3.

AC003081 AB

16 PIN

MB991502

AC001619

HOSE A

AB

AC002283

HOSE A

AB

AC002074

HOSE B

AB

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-323

STEP 3. Check the evaporative emission purge solenoid
valve using the scan tool MB991502. (Actuator test item
08)
(1) Turn the ignition switch to the "ON" position.
(2) Connect the hand vacuum pump to the nipple of the

evaporative emission purge solenoid from which the hoses
have been disconnected.

(3) Apply a vacuum on the hand vacuum pump, and confirm

that the applied vacuum does not fluctuate.
If the vacuum fluctuates, refer to

P.13B-279

, diagnosis step

for evaporative emission purge solenoid trouble code DTC
P0443.

(4) While maintaining the vacuum, carry out the actuator test

with scan tool MB991502.

Q: Does the vacuum pump gauge indicate the atmospheric

pressure when the evaporative emission purge solenoid
is activated?
The evaporative emission purge solenoid valve
operates normally, and the vacuum pump gauge
reading returns to the atmospheric pressure : Go to

Step 32.

The evaporative emission purge solenoid valve
operates normally, but the vacuum pump gauge does
not indicate the atmospheric pressure : Replace the

evaporative emission purge solenoid. Then go to Step
32.

The evaporative emission purge solenoid valve does
not operate normally : Refer to

P.13B-279

, diagnosis step

for evaporative emission purge solenoid trouble code
DTC P0443.

STEP 4. Check for clogging in the evaporator line hose A,
hose B and evaporative emission purge solenoid valve.
(1) Use scan tool MB991502 to activate the evaporative

emission purge solenoid valve.

Q: Are there any clogs?

YES : Go to Step 5.
NO : Go to Step 6.

AC002074

HOSE B

AB

AC002075

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-324

STEP 5. Check for clogging in the evaporator line hose A
and hose B.
(1) Sequentially apply vacuum with a hand vacuum pump

connected to hose A and hose B.

Q: Are there any clogs?

YES : Replace that hose, and perform the purge flow check.

(Refer to GROUP 17, Engine Emission Control

−

Evaporative Emission Control System

−

Purge

Control System Check

P.17-85

.)

NO : Go to Step 32.

AC002283

HOSE A

AB

AC002074

HOSE B

AB