Mitsubishi Galant 9G. Manual - part 1124

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-796

Q: Is the fuel tank pressure between 

−1.5 and 1.5 kPa 

(

−0.443 and 0.443 inHg)?

YES : It can be assumed that this malfunction is intermittent 

(Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

− How to 

Cope with Intermittent Malfunctions 

P.00-14

). Go to 

Step 17.

NO :  Replace the PCM (Refer to 

P.13B-1192

). Then go to 

Step 17   .

STEP 17. Perform the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern (Refer to 

Diagnostic Function 

− OBD-ll Drive Cycle − Procedure 1 − 

Evaporative Emission System Leak Monitor 

P.13B-6

).

(2) Read the diagnostic trouble code (DTC).
Q: Is DTC P0453 set?

YES : Repeat the troubleshooting from Step 2.
NO :  The procedure is complete.

DTC P0455: Evaporative Emission System Leak Detected (Gross Leak)

AC306278

A

B

C

D

E

F

G

O

P

Q

N

M

L

H

I

J

K

AB

INTAKE MANIFOLD PLENUM

FUEL TANK

EVAPORATIVE EMISSION
VENTILATION SOLENOID

CHECK VALVE

EVAPORATIVE EMISSION
PURGE SOLENOID

EVAPORATIVE 
EMISSION CANISTER

ONBOARD REFUELING
VAPOR RECOVERY(ORVR)
VENT VALVE MODULE

SYSTEM DIAGRAM

CHAMBER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-797

.

TECHNICAL DESCRIPTION

• The fuel tank may be under a slight pressure or 

vacuum depending on the state of the Evapora-
tive Emission (EVAP) System. The PCM monitors 
and responds to these pressure/vacuum 
changes. If the pressure/vacuum varies from the 
specified range, the PCM will set DTC P0455.

• The PCM energizes the evaporative emission 

ventilation solenoid to shut off the evaporative 
emission canister outlet port.

• The evaporative emission purge solenoid is acti-

vated to apply engine manifold vacuum to the 
EVAP system.

• 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 vac-
uum is maintained at 2 kPa (0.29 psi).

• The PCM determines whether there is a leak or 

clog in the fuel system by measuring the change 
in vacuum inside the fuel tank.

• The test is stopped when fuel vapor pressure is 

determined to be too high.

.

DESCRIPTIONS OF MONITOR METHODS

• Depressurizing EVAP system by intake manifold 

negative pressure is impossible within specified 
period.

.

MONITOR EXECUTION

• Once per driving cycle.

.

MONITOR EXECUTION CONDITIONS 
(OTHER MONITOR AND SENSOR)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Evaporative emission purge solenoid monitor

• Evaporative emission purge system monitor

• Fuel tank differential pressure sensor monitor

• Evaporative emission ventilation solenoid monitor

• Fuel level sensor monitor

• Fuel temperature sensor monitor

 Sensor (The sensors below are determined to be 

normal)

• Mass airflow sensor

• Barometric pressure sensor

• Intake air temperature sensor

• Engine coolant temperature sensor

.

AC306400

AB

EVAPORATIVE EMISSION CANISTER

AC306388AB

EVAPORATIVE EMISSION
PURGE SOLENOID 

AC305053AC

EVAPORATIVE EMISSION
VENTILATION SOLENOID 

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-798

LOGIC FLOW CHARTS (Monitor Sequence)

.

AC306649

0.04in, 0.02in GROSS LEAK MONITOR

START

YES

YES

YES

YES

YES

NO

NO

NO

NO

NO

MONITORING
CONDITIONS?

DEPRESSURIZE FUEL TANK PRESSURE

GROSS LEAK

MONITORING CONDITIONS

SHUT PURGE LINE

MEASURE REVERTING
PRESSURE :    PFT

PFT > PT

SPECIFIED TIMES

MONITORED

MALFUNCTION

END

SPECIFIED TIMES

HAVE PASSED

MALFUNCTION

(GROSS LEAK)

GOOD

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-799

DTC SET CONDITIONS

Check Conditions A: At Start up

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

upon engine start up.

• The engine coolant temperature is 36°C (97°F) or 

less upon engine start up.

Check Conditions B: For Test to Run

• The engine coolant temperature is 60°C (140°F) 

or greater and the fuel tank is 15 

− 40 percent full.

• The engine coolant temperature is 20°C (68°F) or 

greater and the fuel tank is 40 

− 85 percent full.

• The engine speed is greater than or equal to 

1,600 r/min.

• Barometric pressure is greater than 76 kPa (11 

psi).

• Volumetric efficiency is between 20 and 70 per-

cent.

• The fuel tank temperature is 36°C (97°F) or less.

• The fuel tank differential pressure sensor output 

voltage is 1 

− 4 volts.

Check Conditions C: For Test to Stop

• The intake air temperature is greater than 5°C 

(41

°F).

• When the evaporative emission purge solenoid 

and evaporative emission ventilation solenoid are 
closed, the pressure in the fuel tank rises to 451 
Pa (0.065 psi) or less and the amount of remain-
ing fuel is 15 

− 40 percent of capacity upon 

engine start-up.

• When the evaporative emission purge solenoid 

and evaporative emission ventilation solenoid are 
closed, the pressure in the fuel tank rises to 324 
Pa (0.047 psi) or less and the amount of remain-
ing fuel is 40 

− 85 percent of capacity upon 

engine start-up.

• 10 seconds have elapsed from the start of the 

previous monitoring.

• Monitoring time: 150 seconds.

Judgment Criteria

• The fuel tank internal pressure is 2 kPa (0.29 psi) 

or more after the evaporative emission purge 
solenoid valve has been driven when the fuel 
tank and vapor line were closed.

.

OBD-ll DRIVE CYCLE PATTERN

Refer to Diagnostic Function 

− OBD-ll Drive Cycle − 

Procedure 1 

− Evaporative Emission System Leak 

Monitor 

P.13B-6

.

.

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 valve failed.

• Evaporative emission ventilation solenoid valve 

failed.

• Fuel tank differential pressure sensor failed.

• Evaporative emission canister seal is faulty.

• Evaporative emission canister is clogged.