Mitsubishi Galant 9G. Manual — part 802

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-650

.

CIRCUIT OPERATION

• The PCM (terminal 21) supplies a 5-volt refer-

ence signal to the fuel tank differential pressure
sensor (terminal 3). The fuel tank differential
pressure sensor (terminal 2) is grounded through
the PCM (terminal 22).

• The fuel tank differential pressure sensor (termi-

nal 1) returns a voltage signal to the PCM (termi-
nal 23) that is proportional to the pressure in the
fuel tank.

.

TECHNICAL DESCRIPTION

• The PCM monitors the fuel tank differential pres-

sure sensor output voltage.

• The PCM determines whether the fuel tank differ-

ential pressure sensor signal voltage is within
normal operating parameters.

.

DESCRIPTIONS OF MONITOR METHODS

• Compare purge solenoid status with fuel tank dif-

ferential pressure sensor output voltage.

.

MONITOR EXECUTION

• Continuous.

.

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 ventilation solenoid monitor

Sensor (The sensors below are determined to be

normal)

• Mass airflow sensor

• Barometric pressure sensor

• Intake air temperature sensor

• Engine coolant temperature sensor

• Accelerator pedal position sensor

.

AC305266

CONNECTOR: D-23

AB

D-23 (B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-651

LOGIC FLOW CHARTS (Monitor Sequence)

.

DTC SET CONDITIONS

Check Conditions

• Intake air temperature is greater than 5°C (41°F).

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

• Volumetric efficiency is between 20 and 70 per-

cent.

Judgment Criteria

• When the evaporative emission purge solenoid is

off, the fuel differential pressure sensor output
voltage remains 1.0 volt or less for ten seconds.

Check Conditions

• Intake air temperature is between 5°C (41°F) and

45

°C (113°F) or greater.

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

• Volumetric efficiency is between 20 and 70 per-

cent.

Judgment Criteria

• When the evaporative emission purge solenoid

valve is fully operational (100 percent ratio), the
fuel differential pressure sensor output voltage
remains at 4.0 volts or greater for ten seconds.

.

OBD-ll DRIVE CYCLE PATTERN

Refer to Diagnostic Function

− OBD-ll Drive Cycle −

Procedure 1

− Evaporative Emission System Leak

Monitor

P.13A-6

.

.

NO

YES

CONTINUOUS

FAILURE FOR 10 SECS

START

END

NO

NO

NO

YES

YES

YES

MALFUNCTION

GOOD

MONITORING

CONDITIONS

OUTPUT VOLTAGE

< 1.0V

OUTPUT VOLTAGE

> 4.0V

AC401446

RATIONALITY - HIGH/LOW

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-652

TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CODE TO BE
SET ARE:)

• Malfunction of the fuel tank differential pressure

sensor.

• A damaged harness in the fuel tank differential

pressure sensor circuit.

• Malfunction of the PCM.

.

OVERVIEW OF TROUBLESHOOTING

• DTC P0450 can be set by a faulty fuel tank differ-

ential pressure sensor or related circuit, or PCM
failure.

• To check for system blockage, do a performance

test which uses a mechanical vacuum gauge and
scan tool MB991958 set on the fuel tank differen-
tial pressure sensor (TANK PRS SNSR 73). The
mechanical gauge reading is used to verify scan
tool MB991958 reading. A comparison of the
mechanical gauge with the reading on scan tool
MB991958 will locate a problem in the system.

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

• MB991658: Test Harness Set

• MB991923: Power Plant ECU Check Harness

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-653

STEP 1. Using scan tool MB991958, check data list item 73:
Fuel Tank Differential Pressure Sensor.

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.

(2) Disconnect hose I from the evaporative emission canister,

and plug the hose.

(3) Turn the ignition switch to the "ON" position.
(4) Remove the fuel cap.
(5) Set scan tool MB991958 to the data reading mode.

• Item 73, Fuel Tank Differential Pressure Sensor.

• The fuel tank pressure reading on the scan tool

should be

−1.5 to 1.5 kPa (−0.443 to 0.443 inHg).

(6) Connect the evaporative emission system pressure pump

(Miller number 6872A) to the fuel tank filler tube by using
fuel tank adapter (MLR-8382) and pressurize the fuel tank.

• The fuel tank pressure reading should increase.

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

disconnect scan tool MB991958.

(8) Remove the evaporative emission system pressure pump

(Miller number 6872A) and the fuel tank adapter
(MLR-8382), and reinstall the fuel cap.

(9) Connect hose I to the evaporative emission canister.
Q: Is the fuel tank pressure between

−1.5 and 1.5 kPa

(

−0.443 and 0.443 inHg)?

YES : It can be assumed that this malfunction is intermittent

(Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

− How to

Cope with Intermittent Malfunctions

P.00-14

). Go to

Step 17.

NO : Go to Step 2.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC306778

AB

HOSE I

PLUG

AC306661