MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-355
•
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.
.
DTC SET CONDITIONS
Remaining fuel amount is 15
−
40 percent (fuel level
sensor output voltage is 1.4
−
2.4 volts)
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 fuel temperature is 36
°
C (97
°
F) or less.
•
With in 800 seconds after the engine is started.
•
Engine coolant temperature is higher than 60
°
C
(140
°
F).
•
Power steering pressure switch: "OFF"
•
Barometric pressure is above 76 kPa (11 psi).
•
Fuel tank differential pressure sensor output volt-
age is 1 to 4 volts.
•
Vehicle speed is 20 km/h (12.4 mph) or more.
Test Conditions C: For Test to Stop
•
Intake air temperature is less than
−
10
°
C (14
°
F).
•
When the evaporative emission purge solenoid
and evaporative emission ventilation solenoid are
closed, the pressure rises higher 451 Pa (0.065
psi).
•
The pressure fluctuation width is higher than 647
Pa (0.094 psi).
Judgment Criteria
•
Internal pressure of the fuel tank has changed
more than 785 Pa (0.114 psi) in 20 seconds after
the tank and vapor line were closed.
NOTE: The monitoring time depends on the fuel
level and the temperature in the fuel tank (75
−
125
seconds).
.
DTC SET CONDITIONS
Remaining fuel amount is 40
−
85 percent (fuel level
sensor output voltage is 2.4
−
3.7 volts)
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 fuel temperature is 36
°
C (97
°
F) or less.
•
Engine coolant temperature is less than 20
°
C
(68
°
F).
•
Barometric pressure is above 76 kPa (11 psi).
•
Fuel tank differential pressure sensor output volt-
age is 1 to 4 volts.
Test Conditions C: For Test to Stop
•
Intake air temperature is less than
−
10
°
C (14
°
F).
•
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 has changed
more than 1.9 kPa (0.28 psi) in 128 seconds after
the tank and vapor line were closed.
NOTE: The monitoring time depends on the fuel
level and the temperature in the fuel tank (10
−
14
minutes).
.
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 P0442, a perfor-
mance test is needed. The performance test uses
a mechanical vacuum gauge and scan tool
MB991502 set on the fuel tank differential pres-
sure sensor (TANK PRES SNER 73.) The
mechanical gauge reading is used to verify scan
tool MB991502 reading. A comparison of the
mechanical gauge to scan tool MB991502 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:
•
MB991502: Scan Tool (MUT-II)
