Mitsubishi Galant (2004+). Manual - part 1255

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-713

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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.

.

AC306248

B-20 HARNESS

CONNECTOR:

COMPONENT SIDE

AB

B-20

CONNECTOR: B-20

PCM

AIR
CLEANER

AC305231

CONNECTOR: C-25

AM

C-25

AC305266

CONNECTOR: D-23

AB

D-23 (B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-714

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

.

LOGIC FLOW CHARTS (Monitor Sequence)

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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.

.

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

 

AC306648

RANGE CHECK - MIN/MAX

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-715

OBD-ll DRIVE CYCLE PATTERN
Refer to Diagnostic Function 

− OBD-ll Drive Cycle − 

Procedure 1 

− Evaporative Emission System Leak 

Monitor 

P.13B-5

.

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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 P0452 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.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-716

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.
(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).

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC306778

AC

HOSE H

PLUG