Mitsubishi Galant (2004+). Manual - part 1107

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-121

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• 2 seconds or more have passed since the engine 

starting sequence was completed.

Judgement Criteria

• Intake air temperature sensor output voltage has 

continued to be 4.6 volts or higher [corresponding 
to an air intake temperature of 

−40°C (−40°F) or 

lower] for 2 seconds.

.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function 

− OBD-II Drive Cycle − 

Procedure 6 

− Other Monitor 

P.13B-5

.

.

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

• Intake air temperature sensor failed.

• Open intake air temperature sensor circuit, or 

connector damage.

• PCM failed.

START

OUTPUT VOLTAGE < 0.2V

END

NO

NO

NO

YES

YES

YES

MALFUNCTION

GOOD

CONTINUOUS

FAILURE FOR 2secs

OUTPUT VOLTAGE > 4.6V

MONITORING

CONDITIONS

NO

YES

AK302384

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-122

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 13: 
Intake Air 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 

13, Intake Air Temperature Sensor.

• The intake air 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 

P.00-6

.

NO :  Go to Step 2.

STEP 2. Check harness connector B-10 at the intake air 
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

AK303015

2

1

3

4

AB

B-10 (GR)

CONNECTOR: B-10

HARNESS
CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-123

STEP 3. Check the intake air temperature sensor.
(1) Disconnect the intake air temperature sensor connector 

B-10.

(2) Measure the resistance between intake air temperature 

sensor side connector terminal No. 1 and No. 4.

• There should be continuity. (0.30 − 20 kΩ)

Q: Is the measured resistance between 0.30 and 20 k

Ω?

YES : Go to Step 4.
NO :  Replace the mass airflow sensor. Then go to Step 11.

STEP 4. Measure the sensor supply voltage at intake air 
temperature sensor harness side connector B-10.
(1) Disconnect the connector B-10 and measure at the harness 

side.

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

(3) Measure the voltage between terminal No. 1 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.

AK303015

2

1

3

4

AB

B-10 (GR)

CONNECTOR: B-10

HARNESS
CONNECTOR:
COMPONENT SIDE

1

2

3 4

AK203041

INTAKE AIR TEMPERATURE
SENSOR CONNECTOR

AB

AK303015

2

1

3

4

AB

B-10 (GR)

CONNECTOR: B-10

HARNESS
CONNECTOR:
COMPONENT SIDE

AK303034

2

1

3

4

B-10 HARNESS 
CONNECTOR: 
COMPONENT SIDE

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-124

STEP 5. Measure the sensor supply voltage at PCM 
connector B-22 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 intake air temperature sensor connector 

B-10.

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

AK303016

104

96

94

95

93 92 91

99 98 97

103 102 101 100

108 107 106 105

113 112 111 110 109

CONNECTOR: B-22

B-22 (B)

PCM

AB

HARNESS CONNECTOR: 
COMPONENT SIDE

AIR CLEANER