Mitsubishi Galant. Manual — part 208

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-57

TECHNICAL DESCRIPTION

•

The intake air temperature sensor converts the
intake air temperature to a voltage.

•

The PCM checks whether this voltage is within a
specified range.

DTC SET CONDITIONS

Check Conditions

•

Two seconds or more have passed since the
engine was started.

Judgement Criteria

•

Intake air temperature sensor output voltage has
continued to be 4.6 volts or higher [corresponding
to an air intake temperature of -45

°

C (-49

°

F) or

lower] for 2 seconds.

or

•

Intake air temperature sensor output voltage has
continued to be 0.2 volt or lower [corresponding
to an air intake temperature of 125

°

C (257

°

F) or

higher] for 2 seconds.

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

•

Intake air temperature sensor failed.

•

Open or shorted intake air temperature sensor
circuit, or loose connector.

•

PCM failed.

DIAGNOSIS

Required Special Tools
MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, check data list item 13:
Intake Air Temperature Sensor.

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK"(OFF) position before
connecting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991502 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.00-8

).

NO : Go to Step 2.

AC003081 AB

16 PIN

MB991502

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-58

STEP 2. Check the sensor output voltage at intake air
temperature sensor connector B-14 by backprobing.
(1) Do not disconnect the connector B-14.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 6 and ground by

backprobing.

•

When intake air temperature is 0

°

C(32

°

F), voltage

should be 3.2 and 3.8 volts.

•

When intake air temperature is 20

°

C(68

°

F), voltage

should be 2.3 and 2.9 volts.

•

When intake air temperature is 40

°

C(104

°

F), voltage

should be 1.5 and 2.1 volts.

•

When intake air temperature is 80

°

C(176

°

F), voltage

should be 0.4 and 1.0 volts.

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

Q: Is the voltage normal?

YES : Go to Step 3.
NO : Go to Step 5.

STEP 3. Check connector B-14 at the intake air
temperature sensor for damage.
Q: Is the 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 19.

STEP 4. Using scan tool MB991502, check data list item 13:
Intake Air Temperature Sensor.

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK"(OFF) position before
connecting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991502 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.00-8

).

NO : Replace the PCM. Then go to Step 19.

AKX01524

B-14 CONNECTOR
HARNESS
SIDE VIEW

1 2 3 4 5 6 7

AC

ACX02480

CONNECTOR : B-14

AG

INTAKE AIR
TEMPERATURE
SENSOR

AC003081 AB

16 PIN

MB991502

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-59

STEP 5. Check connector B-14 at intake air temperature
sensor for damage.
Q: Is the 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 19.

STEP 6. Check the intake air temperature sensor.
(1) Disconnect the intake air temperature sensor connector B-

14

(2) Measure the resistance between intake air temperature

sensor side connector terminal 5 and 6.

•

There should be continuity. (0.30

−

1.0 k

Ω

)

NOTE: Check that the circuit is not open loop.

Q: Is the resistance normal?

YES : Go to Step 7.
NO : Replace the volume air flow sensor. Then go to Step

19.

STEP 7. Check the sensor supply voltage at intake air
temperature sensor harness side connector B-14.
(1) Disconnect the connector B-14 and measure at the harness

side.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 6 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 voltage normal?

YES : Go to Step 12.
NO : Go to Step 8.

ACX02480

CONNECTOR : B-14

AG

INTAKE AIR
TEMPERATURE
SENSOR

ACX02480

CONNECTOR : B-14

AG

INTAKE AIR
TEMPERATURE
SENSOR

AKX01407AB

INTAKE AIR TEMPERATURE
SENSOR SIDE CONNECTOR

1 2 3 4 5 6 7

AKX01408

B-14 HARNESS
SIDE CONNECTOR

7 6 5 4 3 2 1

AC

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-60

STEP 8. Check the sensor supply voltage at PCM
connector C-40 by backprobing.
(1) Do not disconnect the PCM connector C-40.
(2) Disconnect the intake air temperature sensor connector B-

14.

(3) Turn the ignition switch to the "ON" position.
(4) Measure the voltage between terminal 64 and ground by

backprobing.

•

Voltage should be between 4.5 and 4.9 volts.

(5) Turn the ignition switch to the "LOCK"(OFF) position.

Q: Is the voltage normal?

YES : Go to Step 9.
NO : Go to Step 10.

STEP 9. Check connector C-40 at PCM for damage.
Q: Is the connector in good condition?

YES : Repair harness wire between intake air temperature

sensor connector B-14 terminal 6 and PCM connector
C-40 terminal 64 because of open circuit. Then go to
Step 19.

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

Connector Inspection(

P.00E-2

). Then go to Step 19.

STEP 10. Check connector C-40 at PCM for damage.
Q: Is the connector in good condition?

YES : Go to Step 11.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection(

P.00E-2

). Then go to Step 19.

AK000286

C-40 CONNECTOR
HARNESS SIDE VIEW

46
57
66

45
56
65

44
55

43
49

54

64

42
48
59

41
47
58

53
63

52
62

51
61

50
60

AC

AK000280

CONNECTOR : C-40

PCM

AV

AK000280

CONNECTOR : C-40

PCM

AV