Mitsubishi Lancer Evolution X. Manual — part 353

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-477

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CIRCUIT OPERATION

• The ECM (terminal No. 114) supplies a 5 volts

reference voltage to the fuel tank differential pres-
sure sensor (terminal No. 3). The ECM (terminal
No. 113) supplies a ground to the fuel tank differ-
ential pressure sensor (terminal No. 2).

• The ECM (terminal No. 112) receives a voltage

signal proportional to the pressure in the fuel tank
from the fuel tank differential pressure sensor
(terminal No. 1).

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TECHNICAL DESCRIPTION

• To determine whether the fuel tank differential

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

• The ECM 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

Fuel tank differential pressure sensor output voltage
is out of specified range.

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MONITOR EXECUTION

Continuous

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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
• Fuel tank temperature sensor monitor
• Fuel level sensor 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

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MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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DTC SET CONDITIONS

Logic Flow Chart (Monitor Sequence)

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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 percent or less when

the engine is started.

Judgement Criterion

• The fuel tank differential pressure sensor output

voltage remains 4.8 volts or greater for 5 sec-
onds.

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FAIL-SAFE AND BACKUP FUNCTION

• None

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OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function − OBD-II Drive Cycle −

Pattern 23

P.13A-9

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

• Fuel tank differential pressure sensor failed.
• Open fuel tank differential pressure sensor cir-

cuit, or connector damage.

• ECM failed.

AK704952

No

Continuous

failure for 5 secs

Start

End

No

No

Yes

Yes

Malfunction

Good

Output voltage

< 0.2V

Output voltage

> 4.8V

Yes

No

Yes

Monitoring
conditions

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-479

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: V.C.I.
• MB991827: M.U.T.-III USB Cable
• MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, check data list item 52:
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 E 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 for item

52, Fuel Tank Differential Pressure Sensor.

• Output voltage should be between 1,500 to 3,500 mV.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

AK704692 AB

Plug

Hose E

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-480

(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 E to the evaporative emission canister.
Q: Is the sensor operating ptoperly?

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.00-15

).

NO : Go to Step 2 .

STEP 2. Measure the ground voltage at fuel tank
differential pressure sensor connector D-21 by
backprobing.
(1) Do not disconnect the connector D-21.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal No. 2 and ground by

backprobing.

• Voltage should be 0.5 volt or less.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage 0.5 volt or less?

YES : Go to Step 6 .
NO : Go to Step 3 .

STEP 3. Check harness connector D-21 at the fuel tank
differential pressure sensor and harness connector B-10
at ECM for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 4 .
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 7 .

STEP 4. Check for open circuit between fuel tank
differential pressure sensor connector D-21 (terminal No.
2) and ECM connector B-10 (terminal No. 113).
NOTE: Check harness after checking intermediate connector
C-47. If intermediate connector is damaged, repair or replace it.
Refer to GROUP 00E, Harness Connector Inspection

P.00E-2

.

Then go to Step 7 .
Q: Is the harness wire in good condition?

YES : Go to Step 5 .
NO : Repair it. Then go to Step 7 .

AK704700

3

2

1

AK704396

D-21 harness
connector:
harness side

AC