Mitsubishi Galant 9G. Manual - part 673

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-134

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CIRCUIT OPERATION

• 5-volt voltage is applied to the engine coolant 

temperature sensor output terminal (terminal No. 
1) from the PCM (terminal No. 93) via the resistor 
in the PCM. The ground terminal (terminal No. 2) 
is grounded with PCM (terminal No. 69).

• The engine coolant temperature sensor is a neg-

ative temperature coefficient type of resistor. It 
has the characteristic that when the engine cool-
ant temperature rises the resistance decreases.

• The engine coolant temperature sensor output 

voltage increases when the resistance increases 
and decreases when the resistance decreases.

.

TECHNICAL DESCRIPTION

• The engine coolant temperature sensor converts 

the engine coolant temperature to a voltage and 
outputs it.

• The PCM checks whether this voltage is within a 

specified range.

.

DESCRIPTIONS OF MONITOR METHODS

Engine coolant temperature sensor output voltage 

does not change for specified period when 
engine coolant temperature sensor output volt-
age at engine start is over 7

°C (45°F).

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MONITOR EXECUTION

Once per driving cycle

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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)

• Not applicable

Sensor (The sensor below is determined to be 

normal)

• Mass airflow sensor

• Engine coolant temperature sensor

• Intake air temperature sensor

.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

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DTC SET CONDITIONS
Logic Flow Chart

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Check Conditions

• Engine coolant temperature was 7°C (45°F) or 

more when the engine started.

Judgement Criteria

• Engine coolant temperature fluctuates within 1°C 

(34

°F) after 5 minutes have passed since the 

engine was started.

• However, time is not counted if any of the follow-

ing conditions are met.

1. Intake air temperature is 60

°C (140°F) or 

more.

2. Mass airflow sensor output is 10 g/sec or less.
3. During fuel shut-off operation.

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OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function

−OBD-II Drive 

Cycle

−Procedure 6−Other Monitor 

P.13A-6

.

.

START

END

YES

NO

NO

YES

MALFUNCTION

GOOD

300secs HAVE PASSED?

|dT| < 1˚C(34˚F)

MONITORING CONDITIONS?

START MEASURING THE MINIMUM AND MAXIMUM

TEMPERATURE FROM ENGINE START

CALCULATE THE DIFFERENCE OF THE MINIMUM AND 

THE MAXIMUM TEMPERATURE FROM ENGINE START;dT

YES

NO

AK401491

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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

• Engine coolant temperature sensor failed.

• Harness damage or connector damage.

• 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 21: 
Engine Coolant Temperature 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) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to the data reading mode for item 

21, Engine Coolant Temperature Sensor.

• The engine coolant temperature and temperature 

shown with the scan tool should approximately match.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
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.00-14

.

NO :  Go to Step 2.

AK303804AB

MB991910

DATA LINK
CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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STEP 2. Check the engine coolant temperature sensor.
(1) Disconnect the engine coolant temperature sensor 

connector B-104.

(2) Remove the engine coolant temperature sensor.

(3) With the temperature sensing portion of engine coolant 

temperature sensor immersed in hot water, measure 
resistance.

Standard value:

14 

− 17 kΩ [at −20°C (−4°F)]

5.1 

− 6.5 kΩ [at 0°C (32°F)]

2.1 

− 2.7 kΩ [at 20°C (68°F)]

0.9 

− 1.3 kΩ [at 40°C (104°F)]

0.48 

− 0.68 kΩ [at 60°C (140°F)]

0.26 

− 0.36 kΩ [at 80°C (176°F)]

(4) Apply 3M

 AAD part number 8731 or equivalent on the 

screw section of the engine coolant temperature sensor.

(5) Install the engine coolant temperature sensor, and tighten 

to the specified torque.

Tightening torque: 30 

± 9 N⋅m (22 ± 7 ft-lb)

Q: Is the measured resistance at the standard value?

YES : Go to Step 3.
NO :  Replace the engine coolant temperature sensor. Then 

go to Step 9.

STEP 3. Check harness connector B-104 at the engine 
coolant temperature sensor 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 9.

AK303815

1

2

AB

CONNECTOR: B-104

B-104 (B)

HARNESS 
CONNECTOR:
COMPONENT SIDE

AKX01622

AKX01623 AB

AK303815

1

2

AB

CONNECTOR: B-104

B-104 (B)

HARNESS 
CONNECTOR:
COMPONENT SIDE