Mitsubishi Galant (2004+). Manual - part 925

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-517

Judgement Criteria (change in the angular accel-

eration of the crankshaft is used for misfire 
detection)

• Misfire has occurred more frequently than 

allowed during the last 200 revolutions [when the 
catalyst temperature is higher than 950

°C 

(1742

°F)].

or

• Misfire has occurred in 15 or more of the last 

1,000 revolutions (corresponding to 1.5 times the 
limit of emission standard). <Federal>

or

• Misfire has occurred in 10 or more of the last 

1,000 revolutions (corresponding to 1.5 times the 
limit of emission standard). <California>

.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function 

− OBD-II Drive Cycle − 

Procedure 6 

− Other Monitor 

P.13A-5

.

.

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

• Ignition system related part(s) failed.

• Poor crankshaft position sensor.

• Incorrect air/fuel ratio.

• Low compression pressure.

• Skipping of timing belt teeth.

• EGR system and EGR valve failed.

• PCM failed.

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

STEP 1. Using scan tool MB991958, check data list item 22: 
Crankshaft Position 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) Start the engine and run at idle.

(3) Set scan tool MB991958 to the data reading mode for item 

22, Crankshaft Position Sensor.

(4) Check the waveform of the crankshaft position sensor while 

keeping the engine speed constant.

• The pulse width should be constant.

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

YES : Go to Step 2.
NO :  Refer to, DTC P0335 

− Crankshaft Position Sensor 

Circuit 

P.13A-542

.

AK303804AB

MB991910

DATA LINK
CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-518

STEP 2. Using scan tool MB991958, check data list item 81: 
Cylinder 1,4 Long-Term Fuel Trim.

(1) Start the engine and run at idle.
(2) Set scan tool MB991958 to the data reading mode for item 

81, Cylinder 1, 4 Long-Term Fuel Trim.

• The fuel trim should be between −12.5 and +12.5 per-

cent when the load is 2,500 r/min (during closed loop) 
after the engine is warmed.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the specification normal?

YES : Go to Step 3.
NO :  Refer to DTC P0171 

− System too Lean (cylinder 1, 4) 

P.13A-403

, DTC P0172 

− System too Rich (cylinder 

1, 4) 

P.13A-412

.

STEP 3. Using scan tool MB991958, check data list item 83: 
Cylinder 2, 3 Long-Term Fuel Trim.

(1) Start the engine and run at idle.
(2) Set scan tool MB991958 to the data reading mode for item 

83, Cylinder 2, 3 Long-Term Fuel Trim.

• The fuel trim should be between −12.5 and +12.5 per-

cent when the load is 2,500 r/min (during closed loop) 
after the engine is warmed.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the specification normal?

YES : Go to Step 4.
NO :  Refer to DTC P0174 

− System too Lean (cylinder 2, 3) 

P.13A-418

, DTC P0175 

− System too Rich (cylinder 

2, 3) 

P.13A-427

.

AK303804AB

MB991910

DATA LINK
CONNECTOR

MB991824

MB991827

AK303804AB

MB991910

DATA LINK
CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-519

STEP 4. Using scan tool MB991958, check data list item 82: 
Cylinder 1, 4 Short-Term Fuel Trim.

(1) Start the engine and run at idle.
(2) Set scan tool MB991958 to the data reading mode for item 

82, Cylinder 1, 4 Short-Term Fuel Trim.

• The fuel trim should be between −10 and +10 percent 

<Federal> or 

−10 and +7.0 percent < California> when 

the load is 2,500 r/min (during closed loop) after the 
engine is warmed.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the specification normal?

YES : Go to Step 5.
NO :  Refer to DTC P0171 

− System too Lean (cylinder 1, 4) 

P.13A-403

, DTC P0172 

− System too Rich (cylinder 

1, 4) 

P.13A-412

.

STEP 5. Using scan tool MB991958, check data list item 84: 
Cylinder 2, 3 Short-Term Fuel Trim.

(1) Start the engine and run at idle.
(2) Set scan tool MB991958 to the data reading mode for item 

84, Cylinder 2, 3 Short-Term Fuel Trim.

• The fuel trim should be between −10 and +10 percent 

<Federal> or 

−10 and +7.0 percent < California> when 

the load is 2,500 r/min (during closed loop) after the 
engine is warmed.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the specification normal?

YES : Go to Step 6.
NO :  Refer to DTC P0174 

− System too Lean (cylinder 2, 3) 

P.13A-418

, DTC P0175 

− System too Rich (cylinder 

2, 3) 

P.13A-427

.

AK303804AB

MB991910

DATA LINK
CONNECTOR

MB991824

MB991827

AK303804AB

MB991910

DATA LINK
CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-520

STEP 6. Check the each ignition coil spark.

(1) Remove the spark plug and connect to the ignition coil.
(2) Ground the spark plug side electrode securely.

• When the engine is cranked, the spark plug should 

spark.

Q: Did it spark?

YES : Go to Step 8.
NO :  Go to Step 7.

STEP 7. Check the spark plugs.

CAUTION

Do not attempt to adjust the gap of the iridium plug. Clean-
ing of the iridium plug may result in damage to the iridium 
and platinum tips. Therefore, if carbon deposits must be 
removed, use a plug cleaner and complete cleaning within 
20 seconds to protect the electrode. Do not use a wire 
brush.
(1) Check the plug gap and replace if the limit is exceeded.

Standard value: 0.7 

− 0.8 mm (0.028 − 0.031 inch)

Limit: 1.0 mm (0.039 inch)

Q: Is the plug gap at the standard value?

YES : Refer to INSPECTION PROCEDURE 31 

− Ignition 

Circuit System 

P.13A-1052

.

NO :  Replace the faulty spark plug. Then go to Step 10.

STEP 8. Check the following items.
(1) Check the following items, and repair or replace the 

defective component.

a. Check for skipped timing belt teeth.
b. Check compression.

c. EGR valve failed.

Q: Are there any abnormalities?

YES : Repair or replace it. Then go to Step 10.
NO :  Go to Step 9.

STEP 9. Check the trouble symptoms.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− OBD-II Drive Cycle − Procedure 6 − 

Other Monitor.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0300 set?

YES : Replace the PCM. Then go to Step 10.
NO :  It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

P.00-6

.

AKX00432

SPARK PLUG

AB

AKX01327AB

IRIDIUM
TIP

PLATINUM
TIP