Mitsubishi Lancer Evolution X. Manual - part 420

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-745

STEP 9. Check the positive crankcase ventilation system.
Refer to GROUP 17, Emission Control System − Positive 

Crankcase Ventilation System − Positive Crankcase Ventilation 

System Check 

P.17-72

.

Q: Is the positive crankcase ventilation system?

YES : Check the following items, and repair or replace the 

defective items.

a. Vacuum leak.
b. Clogged air cleaner.

c. Clogged exhaust system.

d. Check if fuel is contaminated.
e. Check if the injectors are clogged.

f. Check if the foreign materials (water, 

kerosene, etc.) got into fuel.

Then confirm that the malfunction symptom is 

eliminated.

NO :  Repair it. Then confirm that the malfunction symptom 

is eliminated.

Inspection procedure 15: Acceleration shock

.

COMMENT

• There may be an ignition leak accompanying the 

increase in the spark plug demand voltage during 
acceleration.

.

TROUBLESHOOTING HINTS (The most 
likely causes for this case:)

• Malfunction of the ignition system.
• Malfunction of the TC-SST system.
• Malfunction of the ECM.

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.
• MB991827: USB Cable
• MB991910: Main Harness A

NOTE: To protect the TC-SST, the TC-SST-ECU outputs, into 
the ECM, the request signal to reduce the engine torque 
according to the operation condition. Based on the signal, the 
ECM closes the throttle valve, retards the ignition or carries out 
fuel cut. At that time, the engine output seems to temporarily 
reduce, but there is no malfunction.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-746

STEP 1. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).

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) Turn the ignition switch to the "ON" position.
(3) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is any DTC set?

YES : Refer to Diagnostic Trouble Code Chart 

P.13A-48

.

NO :  Go to Step 2.

STEP 2. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).
NOTE: When the TC-SST has a malfunction, the TC-SST-ECU 
might output the request signal of reducing the engine torque in 
order to protect the TC-SST.
(1) Turn the ignition switch to the "ON" position.
(2) Read the TC-SST-DTC.
(3) Turn the ignition switch to the "LOCK" (OFNF) position.
Q: Is the TC-SST-DTC set?

YES : Refer to GROUP 22C, Diagnosis <TC-SST> − 

Diagnostic Trouble Code Chart 

P.22C-17

.

NO :  Go to Step 3 . 

STEP 3. Check the spark plugs.
Refer to GROUP 16, Ignition System − On-vehicle Service − 

Spark Plug Check And Cleaning 

P.16-39

.

Q: Are there any abnormalities?

YES : Replace the spark plug. Then confirm that the 

malfunction symptom is eliminated.

NO :  Go to Step 4.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-747

STEP 4. Check the ignition coil.
Refer to GROUP 16, Ignition System − On-vehicle Service − 

Ignition Coil Check 

P.16-37

.

Q: Are there any abnormalities?

YES : Replace the ignition coil. Then confirm that the 

malfunction symptom is eliminated.

NO :  Check for occurrence of ignition leak. Then confirm 

that the malfunction symptom is eliminated.

Inspection procedure 16: Knocking

.

COMMENT

• Incases such as the above, the cause is probably 

that the detonation control is defective or the heat 
value of the spark plug is inappropriate.

.

TROUBLESHOOTING HINTS (The most 
likely causes for this case:)

• Defective knock sensor.
• Incorrect heat value of the spark plug.
• Poor compression.
• Malfunction of the ECM.

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.
• MB991827: USB Cable
• MB991910: Main Harness A

STEP 1. Using the scan tool MB991958, read the 
diagnostic trouble code (DTC).

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) Turn the ignition switch to the "ON" position.
(3) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is any DTC set?

YES : Refer to Diagnostic Trouble Code Chart 

P.13A-48

.

NO :  Go to Step 2.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-748

STEP 2. Using scan tool MB991958, check data list.
(1) Turn the ignition switch to the "ON" position.
(2) Check the following items of the data list. Refer to Data List 

Reference Table 

P.13A-818

.

a. Item 32: Knock retard.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?

YES : Go to Step 3.
NO :  Refer to DTC P0327 − Knock Sensor Circuit Low Input 

P.13A-383

, DTC P0328 - Knock Sensor Circuit High 

Input 

P.13A-386

.

STEP 3. Check the spark plugs.
Refer to GROUP 16, Ignition System − On-vehicle Service − 

Spark Plug Check And Cleaning 

P.16-39

.

Q: Are there any abnormalities?

YES : Replace the spark plug. Then confirm that the 

malfunction symptom is eliminated.

NO :  Go to Step 4.

STEP 4. Check the compression pressure.
Refer to GROUP 11A, On-vehicle Service − Compression Pres-

sure Check 

P.11A-15

.

Q: Is the compression pressure normal?

YES : Check the following items, and repair or replace the 

defective items.

a. Check if fuel is contaminated.
b. Check if the foreign materials (water, 

kerosene, etc.) got into fuel.

c. Check the octane level of the fuel.

Then confirm that the malfunction symptom is 

eliminated.

NO :  Repair it. Then confirm that the malfunction symptom 

is eliminated.