Mitsubishi Eclipse. Manual - part 552

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-751

• 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 sys-
tem 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)

• Volume airflow sensor

• Barometric pressure sensor

• Intake air temperature sensor

• Engine coolant temperature sensor

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-752

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) <3.0L>

13B-753

• 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 128 sec-

onds after the tank and vapor line were closed.

• 10 seconds have elapsed from the start of the

previous monitoring.

• Monitoring time: 10 − 14 minutes.

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.13B-7

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 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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-754

STEP 1. Using scan tool MB991958, check evaporative
emission system monitor test.

CAUTION

• To prevent damage to scan tool MB991958, always turn

the ignition switch to the "LOCK" (OFF) position before
connecting or disconnecting scan tool MB991958.

• With this monitor, the ECM <M/T> or PCM <A/T> auto-

matically increases the engine speed to 1,600 r/min or
more. Check that the transaxle is set to "neutral" <M/T>
or "P" <A/T> position.

(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Erase the DTCs using scan tool MB991958.
(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 the monitor, keep the accelerator pedal at the idling

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

P.13B-1105

. And adjust to

the standard value.

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

range. When the monitor test starts, the "In Progress" item
on the scan tool MB991958 will change from "NO" to "YES."

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

disconnect scan tool MB991958.

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.

AC303127

MB991911

16-PIN

MB991827

MB991824

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