Mitsubishi Galant 9G. Manual — part 1108

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-732

STEP 16. 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).

(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 H to the evaporative emission canister.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC306778

AC

HOSE H

PLUG

AC306661

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-733

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 : Replace the PCM (Refer to

P.13B-1192

). Then go to

Step 17 .

STEP 17. Perform the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern (Refer to

Diagnostic Function

− OBD-ll Drive Cycle − Procedure 1 −

Evaporative Emission System Leak Monitor

P.13B-6

).

(2) Read the diagnostic trouble code (DTC).
Q: Is DTC P0450 set?

YES : Repeat the troubleshooting from Step 2.
NO : The procedure is complete.

DTC P0451: Evaporative Emission System Pressure Sensor Range/Performance

AC306278

A

B

C

D

E

F

G

O

P

Q

N

M

L

H

I

J

K

AC

INTAKE MANIFOLD PLENUM

FUEL TANK

EVAPORATIVE EMISSION
VENTILATION SOLENOID

CHECK VALVE

EVAPORATIVE EMISSION
PURGE SOLENOID

EVAPORATIVE
EMISSION CANISTER

ONBOARD REFUELING
VAPOR RECOVERY(ORVR)
VENT VALVE MODULE

FUEL TANK DIFFERENTIAL
PRESSURE SENSOR

SYSTEM DIAGRAM

CHAMBER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-734

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-735

.

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 signal voltage.

• The PCM determines whether the fuel tank differ-

ential pressure sensor signal voltage is within
normal operating parameters.

.

DESCRIPTIONS OF MONITOR METHODS

• Detect malfunction if change of fuel tank differen-

tial pressure sensor output voltage during idling
stays large during specified go/stop operations.

.

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)