Mitsubishi Eclipse. Manual - part 274

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-589

STEP 26. Check for clogging in the evaporator line from
hose N.
(1) The clogging test with a hand vacuum pump on the hose N.
Q: Is the hose N in good condition?

YES : Go to Step 27.
NO : Replace the hose N, and reinstall the fuel tank. (Refer

to GROUP 13C, Fuel Tank

P.13C-13

.) Then go to

Step 27.

STEP 27. Test the OBD-II drive cycle.
(1) Confirm the repair by performing the appropriate drive cycle

(Refer to Diagnostic Function

− OBD-ll Drive Cycle −

Procedure 1

− Evaporative Emission System Leak Monitor

P.13A-5

(2) Read the diagnostic trouble code.
Q: Is diagnostic trouble code P0455 set?

YES : Go to Step 1.
NO : This diagnosis is complete.

DTC P0456: Evaporative Emission Control System Leak Detected (Very Small Leak)

AC000195

HOSE N

AC001943AB

EVAPORATIVE EMISSION
PURGE SOLENOID

EVAPORATIVE
EMISSION CANISTER

EVAPORATIVE
EMISSION
VENTILATION
SOLENOID

FUEL TANK

CHECK VALVE A

CHECK
VALVE B

INTAKE MANIFOLD

SYSTEM DIAGRAM

CHAMBER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-590

TECHNICAL DESCRIPTION

• To judge if there is leak in the fuel system, ECM

<M/T> or PCM <A/T> measure the change of the
pressure inside the fuel tank.

• The ECM <M/T > or PCM <A/T> turns on the

evaporative emission ventilation solenoid valve to
shot off the evaporative emission canister outlet
port.

• Then the evaporative emission purge solenoid

valve is driven to set the fuel system into a nega-
tive pressure.

• When the fuel system develops a vacuum of 2

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

• The ECM <M/T> or PCM <A/T> 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.

DESCRIPTIONS OF MONITOR METHODS

• Measure reverting pressure after depressurizing

by intake manifold negative pressure and detect
malfunction if reverting pressure rises largely.

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

AC000183AB

EVAPORATIVE EMISSION CANISTER

FUEL TANK

AC000182

EVAPORATIVE EMISSION
PURGE SOLENOID

AC002035AB

EVAPORATIVE EMISSION
VENTILATION SOLENOID

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-591

LOGIC FLOW CHARTS (Monitor Sequence)

DTC SET CONDITIONS

Test Conditions A: At Start up

• The fuel level sensor output voltage is 2.4 − 3.7

volts when the engine starts (i.e. the amount of
remaining fuel is 40

− 85 percent)

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

when the engine is started.

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

less when the engine is started.

Test Conditions B: For Test to Run

• Barometric pressure is above 76 kPa (11 psi).

• The fuel tank temperature is 33°C (91°F) or less

• Fuel tank differential pressure sensor output volt-

age is 1 to 4 volts.

Test Conditions C: For Test to Stop

• Engine coolant temperature is less than 20°C

(68

°F).

• Intake air temperature is less than −10°C (14°F).

START

END

MONITORING
CONDITIONS?

GROSS LEAK

MONITORING CONDITIONS

SPECIFIED TIMES

MONITORED

SPECIFIED TIMES

HAVE PASSED

YES

DEPRESSURIZE FUEL TANK PRESSURE

YES

SHUT PURGE LINE

MALFUNCTION

(GROSS LEAK)

GOOD

YES

AC210304

0.04in, 0.02in GROSS LEAK MONITOR

MEASURE REVERTING
PRESSURE :

PFT

PFT > PT

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-592

• When the evaporative emission purge solenoid

and evaporative emission ventilation solenoid are
closed, the pressure rises higher 324 Pa (0.047
psi).

Judgment Criteria

• Internal pressure of the fuel tank fluctuate 1177 −

1373 Pa (0.171

− 0.199 psi) or more in 10 sec-

onds after the tank and vapor line were closed.

• ECM monitors for this condition once during drive

cycle.

NOTE: The monitoring time depends on the fuel
level and the temperature in the fuel tank (10

−

minutes.)

OBD-ll DRIVE CYCLE PATTERN
Refer to Diagnostic Function

− OBD-ll Drive Cycle −

Procedure 1

− Evaporative Emission System

Leak Monitor

P.13A-5

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 valve

failed.

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
MB991958 set on the fuel tank differential pres-
sure sensor (TANK PRES SNER 73.) The
mechanical gauge reading is used to verify scan
tool MB991958 reading. A comparison of the
mechanical gauge to scan tool MB991958 deter-
mines the problem in the system.

• Prior to doing the performance test, several sim-

ple inspections are needed to exclude some pos-
sibilities of the symptom.

DIAGNOSIS

Required Special Tool:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

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