Mitsubishi Lancer Evolution X. Manual - part 349

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-461

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) Plug the disconnected end of hose E.
(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.

(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 properly?

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 .

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

AK704692 AB

Plug

Hose E

AK704700

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-462

STEP 2. Check harness connector D-21 at fuel tank 
differential pressure sensor for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 3 .
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 12 .

STEP 3. Measure the sensor supply 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. 3 and ground by 

backprobing.

• Voltage should be between 4.9 and 5.1 volts.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.9 and 5.1 volts?

YES : Go to Step 6 .
NO :  Go to Step 4 .

STEP 4. Check harness connector B-10 at ECM for 
damage.
Q: Is the harness connector in good condition?

YES : Go to step 5 .
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 12 .

STEP 5. Check for harness damage between fuel tank 
differential pressure sensor connector D-21 (terminal No. 
3) and ECM connector B-10 (terminal No. 114).
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 12 .
Q: Is the harness wire in good condition?

YES : Go to Step 11 .
NO :  Repair it. Then go to Step 12 .

3

2

1

AK704395

D-21 harness 
connector: 
harness side

AC

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-463

STEP 6. 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 9 .
NO :  Go to Step 7 .

STEP 7. Check harness connector B-10 at ECM for 
damage.
Q: Is the harness connector in good condition?

YES : Go to Step 8 .
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 12 .

STEP 8. Check for harness damage 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 12 .
Q: Is the harness wire in good condition?

YES : Go to Step 11 .
NO :  Repair it. Then go to Step 12 .

STEP 9. Check harness connector B-10 at ECM for 
damage.
Q: Is the harness connector in good condition?

YES : Go to Step 10 .
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 12 .

3

2

1

AK704396

D-21 harness 
connector: 
harness side

AC

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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STEP 10. Check for harness damage between fuel tank 
differential pressure sensor connector D-21 (terminal No. 
1) and ECM connector B-10 (terminal No. 112).
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 12 .
Q: Is the harness wire in good condition?

YES : Go to Step 11 .
NO :  Repair it. Then go to Step 12 .

STEP 11. Replace the fuel tank differential pressure 
sensor.
(1) Replace the fuel tank differential pressure sensor.
(2) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function − OBD-II Drive Cycle − Pattern 15 

P.13A-9

.

(3) Check the diagnostic trouble code (DTC).
Q: Is DTC P0451 set?

YES : Replace the ECM. When the ECM is replaced, 

register the ID code. Refer to GROUP 42B, Diagnosis 
− ID Code Registration Judgment Table <Vehicles with 

KOS> 

P.42B-11

 or GROUP 42C, Diagnosis − ID Code 

Registration Judgment Table <Vehicles with WCM> 

P.42C-9

. Then go to Step 12 .

NO :  The inspection is complete.

STEP 12. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function − OBD-II Drive Cycle − Pattern 15 

P.13A-9

.

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

YES : Repeat the troubleshooting.
NO :  The inspection is complete.