Mitsubishi Galant. Manual — part 267

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-293

DTC P0450: Fuel Tank Pressure Sensor Rationality: Noise

AC001944

CHECK VALVE A

CHECK
VALVE B

EVAPORATIVE
EMISSION CANISTER

FUEL TANK

EVAPORATIVE
EMISSION
VENTILATION
SOLENOID

EVAPORATIVE EMISSION
PURGE SOLENOID

INTAKE MANIFOLD

SYSTEM DIAGRAM

A

B

C

D

E

F

G

Q

R

I

H

K

J

L

N

O

M

P

AC

FUEL TANK DIFFERENTIAL
PRESSURE SENSOR

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-294

Fuel Tank Differential Pressure Sensor Circuit

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-295

CIRCUIT OPERATION

•

A 5-volt voltage is supplied to the power terminal
of the fuel tank differential pressure sensor
(terminal 3) from the PCM (terminal 46.) The
ground terminal (terminal 2) is grounded with the
PCM (terminal 57.)

•

A voltage proportional to the pressure in the fuel
tank is sent from the output terminal of the fuel
tank differential pressure sensor (terminal 1) to
the PCM (terminal 92.)

TECHNICAL DESCRIPTION

•

To judge if the fuel tank differential pressure
sensor is defective, the PCM monitors the fuel
tank differential pressure sensor output voltage.

•

There are three different sets (A, B, C) of test
conditions and the judgment criteria. Based on
these test conditions and judgment criteria, the
PCM judges if the fuel tank differential pressure
sensor output voltage is normal.

NOTE: In rare cases, this DTC may be also set
under some fuel and driving conditions regardless of
the fuel pressure sensor output voltage when the fuel
system is clogged.

DTC SET CONDITIONS

Test Conditions: Electrical noise

•

Idle switch: ON.

•

Vehicle speed is 1.5 km/h (0.93 mph) or less.

Test Conditions: Judgment Criteria

•

The PCM looks for rapid voltage changes
(electrical noise) equal to 20 or more spikes of
0.2 volts or more in 25 millisecond averaged
blocks.

•

The PCM must see this activity during 8
consecutive idling periods from engine starting.

AC005041AB

CONNECTOR:C-17

AC005043

CONNECTORS : C-40, C-41

C-41

C-40

PCM

AB

AC005042 AB

CONNECTOR:C-71

AC002041AC

CONNECTOR: D-11

FUEL TANK DIFFERENTIAL
PRESSURE SENSOR

AC005044 AB

CONNECTOR:D-15

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-296

NOTE: Rapid voltage occurs due to fuel sloshing
during refuelling. However, when the PCM sees
the activity mentioned above 8 consecutive
times, it judges that an electrical noise is present.

NOTE: The PCM determines that the engine is
not idling if all of the following conditions are met.

.

•

Engine speed is higher than 2,500 r/min.

•

Vehicle speed is 15 km/h (9.3 mph) or more.

•

Volumetric efficiency is 55 percent or more.

TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:

•

Fuel tank differential pressure sensor failed.

•

Open or shorted fuel tank differential pressure
sensor circuit, or loose connector.

•

PCM failed.

•

Blockage of evaporative emission system
(causing high pressure.)

OVERVIEW OF TROUBLESHOOTING

•

The DTC P0450 can be set if either of the
following conditions occur:

1. Faulty fuel differential pressure sensor,

related circuit, or PCM.

2. Faulty fuel filler neck evaporative emission

ventilation solenoid or blocked vapor line.

•

To check a system blockage, do a performance
test which uses a mechanical vacuum gauge and
the scan tool MB991502 set on the fuel tank
differential pressure sensor (TANK PRS
SNSR73.)
The mechanical gauge reading is used to verify
the scan tool MB991502 reading.
A comparison of the mechanical gauge to the
scan tool MB991502 determines the problem in
the system.

DIAGNOSIS

Required Special Tools:

•

MB991502: Scan Tool (MUT-II)

•

MB991658: Test Harness Set

STEP 1. Using scan tool MB991502, check data list item 73:
Fuel Tank Differential Pressure Sensor.

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to "LOCK" (OFF) position before
connecting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Remove the fuel cap.
(4) Set scan tool MB991502 to the data reading mode for item

73, Fuel Tank Differential Pressure Sensor.

•

The fuel tank pressures should be -1.5 to 1.5kPa.

(5) Connect an evaporative emission system pressure pump to

the fuel filler neck, and apply pressure.

•

The scan tool reading should increase.

Q: Is the scan tool reading within the specified value?

YES : Go to Step 20.
NO : Go to Step 2.

AC003081 AB

16 PIN

MB991502

AC000186