Mitsubishi Montero (2004+). Manual — part 272

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-575

STEP 15. 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.13A-4

).

(2) Read the diagnostic trouble code (DTC).
Q: Is DTC P0451 set?

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

DTC P0452: Evaporative Emission System Pressure Sensor Low Input

AC203991

SYSTEM DIAGRAM

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

Q

S

R

P

FUEL TANK

CHECK VALVE B

CHECK VALVE A

EVAPORATIVE
EMISSION
PURGE
SOLENOID

EVAPORATIVE EMISSION
VENTILATION SOLENOID

EVAPORATIVE
EMISSION
CANISTER

VENT PIPE
ASSEMBLY

AC

FUEL TANK DIFFERENTIAL
PRESSURE SENSOR

ONBOARD REFUELING
VAPOR RECOVERY(ORVR)
VENT VALVE MODULE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-576

FUEL TANK
DIFFERENTIAL
PRESSURE
SENSOR

POWERTRAIN CONTROL
MODULE (PCM)

AC309251

Fuel Tank Differential Pressure Sensor Circuit

AB

FUEL TANK
DIFFERENTIAL
PRESSURE
SENSOR

POWERTRAIN CONTROL
MODULE (PCM)

AC309251

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-577

.

CIRCUIT OPERATION

• The PCM (terminal 97) 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 96).

• The fuel tank differential pressure sensor (termi-

nal 1) returns a voltage signal to the PCM (termi-
nal 82) 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

AC203998

CONNECTOR: D-112

AB

D-112

AC203993

CONNECTORS: D-134, D-135

AB

D-134
(GR)

D-135
(GR)

PCM

AC203999

CONNECTORS: E-111, E-113

AB

E-113

E-111

AC204000

CONNECTOR: F-07

AB

F-07 (B)

ACX00218

CONNECTOR : G-05

AQ

G-05 (B)

SECOND SEAT UNDER
SERVICE HOLE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-578

.

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.

.

OBD-ll DRIVE CYCLE PATTERN
Refer to Diagnostic Function

− OBD-ll Drive Cycle −

Procedure 1

− Evaporative Emission System Leak

Monitor

P.13A-4

.

.

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.

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

AC210306

RANGE CHECK - MIN/MAX