Mitsubishi Eclipse. Manual - part 547

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-731

• The ECM <M/T> or PCM <A/T> determines if 

there is leak or clog in the fuel system by measur-
ing 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

• 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)

• 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-732

LOGIC FLOW CHARTS (Monitor Sequence)

.

DTC SET CONDITIONS

Test Conditions A: At Start up

• 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

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

more <i.e. the amount of remaining fuel is 15 

− 40 

percent>.

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

more <i.e. the amount of remaining fuel is 40 

− 85 

percent>.

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

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

START

END

MONITORING 
CONDITIONS?

GROSS LEAK

MONITORING CONDITIONS

SPECIFIED TIMES 

MONITORED

SPECIFIED TIMES 

HAVE PASSED

YES

NO

DEPRESSURIZE FUEL TANK PRESSURE

NO

YES

YES

YES

SHUT PURGE LINE

MALFUNCTION

MALFUNCTION

(GROSS LEAK)

GOOD

YES

NO

NO

NO

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-733

• Volumetric efficiency is between 20 and 70 per-

cent.

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

• Fuel tank differential pressure sensor output volt-

age 1 

− 4 volts.

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 higher 451 Pa (0.065 
psi) <i.e. the amount of remaining fuel is 15 

− 40 

percent>.

• When the evaporative emission purge solenoid 

and evaporative emission ventilation solenoid are 
closed, the pressure rises higher 324 Pa (0.047 
psi) <i.e. the amount of remaining fuel is 40 

− 85 

percent>.

• 10 seconds have elapsed from the start of the 

previous monitoring.

• Monitoring time: 136 seconds.

Judgment Criteria

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

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

NOTE: The monitoring time (136 seconds) depends 
on the fuel level and the temperature in the fuel tank.

.

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.

• 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 perfor-

mance test is needed. The performance test uses 
a mechanical vacuum gauge and scan tool 
MB991958mb991958 set on the fuel tank differ-
ential pressure sensor (TANK PRES SNER 73.) 
The mechanical gauge reading is used to verify 
scan tool MB991958 reading. A comparison of 
the mechanical gauge reading to scan tool 
MB991958 reading determines the reading prob-
lem 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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-734

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 the 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."

Q: What is displayed on the scan tool MB991958?

"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

AB

MB991911

16-PIN

MB991827

MB991824