Mitsubishi Lancer Evolution X. Manual - part 351

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-469

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

• MB992110: Power Plant ECU Check Harness

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)

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(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 .

STEP 2. 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 8 .
NO :  Go to Step 3 .

STEP 3. Check 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 12 .

AK704700

3

2

1

AK704395

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 4. Measure the sensor supply voltage at ECM 
connector B-10 by using power plant ECU check harness 
special tool MB992110.
(1) Disconnect all ECM connectors. Connect the power plant 

ECU check harness special tool MB992110 between the 
separated connectors.

(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 114 and ground.

• 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 7 .
NO :  Go to Step 5 .

STEP 5. Check harness connector D-21 at the fuel tank 
differential pressure sensor for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 6 .
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 12 .

STEP 6. Check for short circuit to ground 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 .

AK604171

ECM

AB

Body side harness 

MB992110

82 81 80 79 78 77 76 75 74 73 72 71

94 93 92 91 90 89 88 87 86 85 84 83

99 98 97 96 95

100

101

102

103

104

105

106

112

113

114

109 108

107

110

111

115

116

117

118

AK704397 AB

Power plant ECU
check harness connector

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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STEP 7. Check harness connector D-21 at the fuel tank 
differential pressure sensor for damage.
Q: Is the harness connector in good condition?

YES : Check harness connector C-47 at intermediate 

connector for damage, and repair or replace as 
required. Refer to GROUP 00E, Harness Connector 
Inspection 

P.00E-2

. If intermediate connector is in 

good condition, repair harness wire between fuel tank 
differential pressure sensor connector D-21 (terminal 
No. 3) and ECM connector B-10 (terminal No. 114) 
because of open circuit. Then go to Step 12 .

NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 12 .

STEP 8. Check harness connector D-21 at the fuel tank 
differential pressure sensor and connector B-10 at ECM for 
damage.
Q: Is the harness connector in good condition?

YES : Go to Step 9 .
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 12 .