Mitsubishi Galant 9G. Manual - part 1043

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-472

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• 2 seconds or more have passed since the engine 

starting sequence was completed.

Judgement Criteria

• Sensor output voltage has continued to be 4.6 

volts or higher for 2 seconds.

.

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function 

− OBD-II Drive Cycle − 

Procedure 6 

− Other Monitor 

P.13B-6

.

.

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

• Fuel tank temperature sensor failed.

• Open fuel tank temperature sensor circuit, har-

ness damage, or connector damage.

• PCM failed. 

START

MONITORING

CONDITIONS

END

NO

NO

NO

YES

YES

YES

MALFUNCTION

GOOD

OUTPUT VOLTAGE

< 0.1V

CONTINUOUS

FAILURE FOR 2secs

OUTPUT VOLTAGE

> 4.6V

NO

YES

AK302403

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-473

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

• MB991923: Power Plant ECU Check Harness

STEP 1. Using scan tool MB991958, check data list item 
4A: Fuel Tank 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 

4A, Fuel Tank Temperature Sensor.

• Approximately the same as the ambient air temperature 

when the engine is cooled.

(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.

STEP 2. Check harness connector D-18 at the fuel tank 
temperature 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 11.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AK303840

1

2

3

4

5

SERVICE
HOLE

AB

CONNECTOR: D-18

D-18 (GR)

HARNESS 
CONNECTOR: 
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-474

STEP 3. Check the fuel tank temperature sensor.
(1) Disconnect the fuel tank temperature sensor connector 

D-18.

(2) Measure the resistance between terminal No. 1 and No. 3 

of the fuel tank temperature sensor.

Standard value:

0.5 

− 12.0 kΩ

Q: Is the measured resistance between 0.5 and 12.0 k

Ω?

YES : Go to Step 4.
NO :  Replace the fuel tank temperature sensor. Then go to 

Step 11.

STEP 4. Check the sensor supply voltage at fuel tank 
temperature sensor harness side connector D-18.
(1) Disconnect the connector D-18 and measure at the harness 

side.

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

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

• Voltage should be between 4.5 and 4.9 volts.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.5 and 4.9 volts?

YES : Go to Step 8.
NO :  Go to Step 5.

AK303840

1

2

3

4

5

SERVICE
HOLE

AB

CONNECTOR: D-18

D-18 (GR)

HARNESS 
CONNECTOR: 
COMPONENT SIDE

1

2 3

4

5

AK203165

FUEL TANK TEMPERATURE
SENSOR CONNECTOR

AB

AK303840

1

2

3

4

5

SERVICE
HOLE

AB

CONNECTOR: D-18

D-18 (GR)

HARNESS 
CONNECTOR: 
COMPONENT SIDE

1

2

3

4

5

AK303091

D-18 HARNESS 
CONNECTOR: 
COMPONENT SIDE

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-475

STEP 5. Check the sensor supply voltage at PCM 
connector B-20 by using power plant ECU check harness 
special tool MB991923.
(1) Disconnect the all PCM connectors and connect power 

plant ECU check harness special tool MB991923 between 
the separated connectors.

(2) Disconnect the fuel tank temperature sensor connector 

D-18.

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

AK303092

25

21

24 23 22

29 28 27 26

34 33 32 31 30

38 37 36 35

43 42 41 40 39

CONNECTOR: B-20

B-20

PCM

AB

HARNESS CONNECTOR: 
COMPONENT SIDE

AIR CLEANER

AK203002

25

21

24 23 22

29 28 27 26

34 33 32 31 30

38 37 36 35

43 42 41 40 39

AB

POWER PLANT ECU 
CHECK HARNESS CONNECTOR

MB991923

PCM