Mitsubishi Galant 9G. Manual — part 953

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-112

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 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) Remove the mass airflow sensor from the air intake hose.

(3) Turn the ignition switch to the "ON" position.
(4) Set scan tool MB991958 to the data reading mode for item

13, Intake Air Temperature Sensor.

(5) Heating the sensor using a hair drier.

• The indicated temperature increases.

NOTE: Do not allow it to increase over 80

°

C (176

°

F).

(6) Turn the ignition switch to the "LOCK" (OFF) position.
(7) Attach the mass airflow sensor.
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.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AK302200 AB

INTAKE AIR
TEMPERATURE
SENSOR

MASS AIRFLOW
SENSOR

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-113

STEP 2. 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.

(3) Measure resistance while heating the sensor using a hair

drier.

Standard value:

13

− 17 kΩ [at −20°C (−4°F)]

5.3

− 6.7 kΩ [at 0°C (32°F)]

2.3

− 3.0 kΩ [at 20°C (68°F)]

1.0

− 1.5 kΩ [at 40°C (104°F)]

0.56

− 0.76 kΩ [at 60°C (140°F)]

0.30

− 0.45 kΩ [at 80°C (176°F)]

Q: Is the measured resistance at the standard value?

YES : Go to Step 3.
NO : Replace the mass airflow sensor. Then go to Step 9.

STEP 3. 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 4.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 9.

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

AK203040 AB

INTAKE AIR
TEMPERATURE
SENSOR

MASS AIRFLOW
SENSOR

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-114

STEP 4. Check the continuity at intake air temperature
sensor harness side connector B-10.

(1) Disconnect the connector B-10 and measure at the harness

side.

(2) Check for the continuity between terminal No. 4 and

ground.

• Should be less than 2 ohms.

Q: Does continuity exist?

YES : Go to Step 7.
NO : Go to Step 5.

STEP 5. Check harness connector B-21 at PCM for
damage.

Q: Is the harness connector in good condition?

YES : Go to Step 6.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 9.

AK303015

2

1

3

4

AB

B-10 (GR)

CONNECTOR: B-10

HARNESS
CONNECTOR:
COMPONENT SIDE

2

1

3

4

AK303019

B-10 HARNESS
CONNECTOR:
COMPONENT SIDE

AB

AK303018

55

56

54 53 52 51

57

62 61 60 59 58

63

69 68 67 66 65 64

70

75 74 73 72 71

76

82 81 80 79 78 77

83

CONNECTOR: B-21

PCM

AB

HARNESS CONNECTOR:
COMPONENT SIDE

AIR CLEANER

B-21 (B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-115

STEP 6. Check for open circuit and harness damage
between intake air temperature sensor connector B-10
(terminal No. 4) and PCM connector B-21 (terminal No. 69).

Q: Is the harness wire in good condition?

YES : Replace the PCM. Then go to Step 9.
NO : Repair it. Then go to Step 9.

AK303015

2

1

3

4

AB

B-10 (GR)

CONNECTOR: B-10

HARNESS
CONNECTOR:
COMPONENT SIDE

AK303018

55

56

54 53 52 51

57

62 61 60 59 58

63

69 68 67 66 65 64

70

75 74 73 72 71

76

82 81 80 79 78 77

83

CONNECTOR: B-21

PCM

AB

HARNESS CONNECTOR:
COMPONENT SIDE

AIR CLEANER

B-21 (B)