Mitsubishi Eclipse. Manual - part 533

 

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Mitsubishi Eclipse. Manual - part 533

 

 

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-675

.

CIRCUIT OPERATION

• A 5-volt voltage is supplied to the power terminal 

of the fuel tank differential pressure sensor (ter-
minal 3) from the ECM (terminal 42) <M/T> or 
PCM (terminal 46) <A/T>. The ground terminal 
(terminal 2) is grounded with the ECM (terminal 
49) <M/T> or PCM (terminal 57) <A/T>.

• A voltage proportional to the pressure in the fuel 

tank is sent from the output terminal of the fuel 
tank differential pressure sensor (terminal 1) to 
the ECM (terminal 93) <M/T> or PCM (terminal 
92) <A/T>.

.

TECHNICAL DESCRIPTION

• To judge if the fuel tank differential pressure sen-

sor is defective, the ECM <M/T> or PCM <A/T> 
monitors the fuel tank differential pressure sensor 
output voltage.

• Based on the test conditions and judgment crite-

ria, the ECM <M/T> or PCM <A/T> judges if the 
fuel tank differential pressure sensor output volt-
age is normal.

.

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

AC001741 AJ

CONNECTOR: C-28

AC001689AN

CONNECTORS: C-58, C-62<M/T>,
C-55, C-59 <A/T>

ECM <M/T>
OR
PCM <A/T>

C-62 
<M/T>

C-58 <M/T>,
C-59 <A/T>

C-55 
<A/T>

AC001991

CONNECTOR: C-90

CONNECTOR
BLOCK (LH)

AI

AC001787AD

CONNECTOR: D-16

AC103356

FUEL TANK

AD

CONNECTOR: D-18
FUEL TANK DIFFERENTIAL 
PRESSURE SENSOR

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-676

 Sensor (The sensors below are determined to be 

normal)

• Volume airflow sensor

• Barometric pressure sensor

• Intake air temperature sensor

• Engine coolant temperature sensor

.

LOGIC FLOW CHARTS (Monitor Sequence)

.

DTC SET CONDITIONS

Test Conditions: Electrical noise

• Throttle valve is closed.

• Vehicle speed is 1.5 km/h (0.9 mph) or less.

START 

YES

 

NO 

NO

 

OFF-IDLING CONDITION

 

IDLING CONDITION?

 

F1 = 0 

END 

NO

NO

YES 

YES

 

MALFUNCTION

 

F1 > 20 

SPECIFIED TIMES

MONITORED

 

FTPS OUTPUT

 

VOLTAGE      > 0.2V 

FLUCTUATION

 

NO 

YES

 

YES

 

F1 = F1 + 1 

GOOD

 

YES

 

NO

 

 

OFF-IDLING CONDITION

AC210307

RATIONALITY - NOISE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-677

Judgment Criteria

• The event that the output voltage from the fuel 

tank differential pressure sensor changes by 0.2 
volts or more (i.e. sudden pressure fluctuation) is 
counted at least twenty times during one engine 
idling, and then consecutively eight times during 
normal driving condition.
NOTE: If the number of the sudden pressure fluc-
tuation does not reach twenty during one engine 
idling, the counter will be reset to zero. If the igni-
tion switch is turned off, it will be also reset to 
zero.
NOTE: The conditions for deviating from idling 
operation are as follows:

.

Engine speed is higher than 2,500 r/min.

Vehicle speed is 15 km/h (9.3 mph) or more.

Volumetric efficiency is 55 percent or more.

.

OBD-ll DRIVE CYCLE PATTERN
Refer to Diagnostic Function 

− OBD-ll Drive Cycle − 

Procedure 1 

− Evaporative Emission System Leak 

Monitor 

P.13B-7

.

.

TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:

• Fuel tank differential pressure sensor failed.

• Damaged harness in the fuel tank differential 

pressure sensor circuit.

• ECM <M/T> or PCM <A/T> failed.

.

OVERVIEW OF TROUBLESHOOTING

•  DTC P0451 can be set if either of the following 

conditions occur:

1. Faulty fuel differential pressure sensor, 

related circuit, or ECM <M/T> or PCM <A/T>.

• To check a 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 to scan tool MB991958 deter-
mines the problem in the system.

.

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

• MB991658: Test Harness Set

• MB991709: Test Harness Set

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-678

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 

side, and plug the hose from which the pipes have been 
disconnected.

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

73, Fuel Tank Differential Pressure Sensor.

• The fuel tank pressures should be −1.5 to 1.5  kPa 

(

−0.443 to 0.443 inHg.)

(6) Connect an evaporative emission system pressure pump to 

the fuel filler neck, and apply pressure.

• The scan tool reading should increase.

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

disconnect scan tool MB991958.

Q: Is the scan tool reading within the specified value?

YES : Go to Step 22.
NO :  Go to Step 2.

AC303127

AB

MB991911

16-PIN

MB991827

MB991824 

AC002072 AB

HOSE I

AC000186

 

 

 

 

 

 

 

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