Mitsubishi Galant 9G. Manual - part 1119

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-776

FUEL TANK 
DIFFERENTIAL 
PRESSURE 
SENSOR

POWERTRAIN 
CONTROL 
MODULE

Fuel Tank Differential Pressure Sensor Circuit

AC306128

AC306248

B-20 HARNESS

CONNECTOR:

COMPONENT SIDE

AB

B-20

CONNECTOR: B-20

PCM

AIR
CLEANER

AC305231

CONNECTOR: C-25

AM

C-25

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-777

.

CIRCUIT OPERATION

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

ence voltage to the fuel tank differential pressure 
sensor (terminal 3). The PCM (terminal 22) sup-
plies a ground to the fuel tank differential pres-
sure sensor (terminal 2).

• The PCM (terminal 23) receives a voltage signal 

proportional to the pressure in the fuel tank from 
the fuel tank differential pressure sensor (terminal 
1).

.

TECHNICAL DESCRIPTION

• To determine whether the fuel tank differential 

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

• The PCM judges if the fuel tank differential pres-

sure 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.

.

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) <3.8L ENGINE>

13B-778

LOGIC FLOW CHARTS (Monitor Sequence)

.

DTC SET CONDITIONS

Check Conditions

• 2 seconds or more have passed since the start-

ing sequence was completed.

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

• Remaining fuel level is 85% or less when the 

engine is started.

Judgment Criteria

• The fuel tank differential pressure sensor output 

voltage remains 4.8 volt or greater for 5 seconds.

.

OBD-ll DRIVE CYCLE PATTERN

Refer to Diagnostic Function 

− OBD-ll Drive Cycle − 

Procedure 1 

− Evaporative Emission System Leak 

Monitor 

P.13B-6

.

.

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

• Malfunction of the fuel tank differential pressure 

sensor.

• Open or shorted fuel tank differential pressure 

sensor circuit.

• Malfunction of the PCM.

.

AC401447

RANGE CHECK - MIN. / MAX.

NO

YES 

CONTINUOUS

FAILURE FOR 5 SECS

START 

END 

NO 

NO

NO

YES 

YES 

 

YES 

MALFUNCTION

 

GOOD 

MONITORING

 

CONDITIONS

 

OUTPUT VOLTAGE

 

< 1.0V

OUTPUT VOLTAGE

 

> 4.8V 

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-779

OVERVIEW OF TROUBLESHOOTING

• DTC P0453 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 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

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 H from the evaporative emission canister, 

and plug the hose.

(3) Turn the ignition switch to the "ON" position.
(4) Remove the fuel cap.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC306778

AC

HOSE H

PLUG