Mitsubishi Eclipse / Eclipse Spyder (2000-2002). Service and repair manual — part 280

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-319

Fuel Tank Diferential Pressure Sensor Circuit

AC005149

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-320

CIRCUIT OPERATION

•

A 5-volt voltage is supplied to the power terminal
of the fuel tank differential pressure sensor
(terminal 3) from the ECM (terminal 42) <M/T> or
PCM (terminal 46) <A/T>. The ground terminal
(terminal 2) is grounded with the ECM (terminal
49) <M/T> or PCM (terminal 57) <A/T>.

•

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 ECM (terminal 93) <M/T> or PCM (terminal
92) <A/T>.

TECHNICAL DESCRIPTION

•

To judge if the fuel tank differential pressure
sensor is defective, the ECM <M/T> or PCM <A/
T> 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
ECM <M/T> or PCM <A/T> 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 A: Fuel tank differential pressure

sensor output voltage is less than the upper
limit of the predetermined value

•

Intake air temperature is higher than 5

°

C (41

°

F.)

•

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

•

Volumetric efficiency is between 25 and 80
percent.

•

Vehicle speed is 30 km/h (18.7 mph) or more.

AC001741

CONNECTOR: C-28

AM

AC001689AN

CONNECTORS: C-58, C-62<M/T>,
C-55, C-59 <A/T>

ECM <M/T>
OR
PCM <A/T>

C-62
<M/T>

C-58 <M/T>,
C-59 <A/T>

C-55
<A/T>

AC001800 AF

CONNECTOR: C-90

AC001787AD

CONNECTOR: D-16

AC002041AB

CONNECTOR: D-18

FUEL TANK DIFFERENTIAL
PRESSURE SENSOR

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-321

•

Evaporative emission purge solenoid is driven at
a 100 percent duty when the intake air
temperature is between 5 and 45

°

C (41

−

113

°

F.)

Judgement Criteria A

•

The sensor output voltage remains 4.0 V or more
for 10 seconds or more.

Test Conditions B: Fuel tank differential pressure

sensor output voltage is more than the lower
limit of the predetermined value

•

Intake air temperature is higher than 5

°

C (41

°

F.)

•

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

•

Volumetric efficiency is between 25 and 80
percent.

•

Vehicle speed is 30 km/h (18.7 mph) or more.

•

Evaporative emission purge solenoid is not
driven when the intake air temperature is 5

°

C

(41

°

F) or more.

Judgment Criteria B

•

The sensor output voltage remains less than 1.0
V for 10 seconds 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.

•

ECM failed <M/T>.

•

PCM failed <A/T>.

•

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 ECM <M/T> or PCM <A/T>.

2. Faulty fuel filler neck evaporative emission

ventilation solenoid or blocked vapor line.

•

If the fuel filler neck evaporative emission
ventilation solenoid is faulty and stays closed or
the vapor line is blocked, the pressure inside the
fuel tank is increased as the evaporative fuel is
not purged especially at hot ambient
temperatures. Once the pressure inside the fuel
tank reaches 5 kPa (0.073 psi), the sensor output
voltage also reaches 4.0 volts. This will set the
DTC P0451.

•

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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-322

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to "LOCK" (OFF) position before
connecting or disconnecting scan tool MB991502.

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

STEP 2. Check the output circuit voltage at intermediate
connector D-16.
(1) Remove the rear seat cushion. (Refer to GROUP 52A, Rear

Seat

P.52A-23

.)

(2) Remove the protector.
(3) Do not disconnect intermediate connector D-16.
(4) Use special tools (MB991658 and MB991709) to connect

terminals 5, 6 and 8 between connectors of the
intermediate connector, respectively.

(5) Turn the ignition switch to the "ON" position.
(6) Remove the fuel cap.
(7) Measure the voltage between terminal 5 and ground by

backprobing.

•

Voltage should be between 2.0 and 3.0 volts.

(8) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the multi-meter reading within the specified value?

YES : Go to Step 10.
NO : Go to Step 3.

AC001252

MB991502

16 PIN

AB

AC000186

AC002079 AB

MB991709

MB991658