Mitsubishi Galant. Manual — part 88

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-33

CIRCUIT OPERATION

•

The volume air flow sensor power is supplied
from the MFI relay (terminal 1), and the ground is
provided on the PCM (terminal 57).

•

5-volt power is applied to the volume air flow
sensor output terminal (terminal 3) from the PCM
(terminal 65). The volume air flow sensor
generates a pulse signal when the output
terminal and ground are opened/closed (opened/
short).

TECHNICAL DESCRIPTION

•

While the engine is running, the volume air flow
sensor outputs a pulse signal which corresponds
to the volume of air flow.

•

The PCM checks whether the frequency of this
signal output by the volume air flow sensor while
the engine is running is at or above the set value.

DTC SET CONDITIONS

Check Conditions

•

Throttle position sensor voltage is 1.5 volts or
higher.

•

Engine speed is higher than 2,000 r/min.

Judgement Criteria

•

Volume air flow sensor output frequency has
continued to be 60 Hz or lower for 2 seconds.

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

•

Volume air flow sensor failed.

•

Open or shorted volume air flow sensor circuit, or
loose connector.

•

PCM failed.

•

Air leak between volume air flow sensor and
throttle body.

DIAGNOSIS

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

ACX02480

CONNECTOR : B-14

AC

VOLUME AIR
FLOW SENSOR

AK000280

CONNECTORS : C-39, C-40

C-39 C-40

PCM

AU

AK000555AB

CONNECTOR : A-21X

MFI RELAY

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-34

STEP 1. Using scan tool MB991502, check data list item 12:
Volume Air Flow 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) Start the engine and run at idle.
(3) Set scan tool MB991502 to the data reading mode for item

12, Volume Air Flow Sensor.

(4) Warm up the engine to normal operating temperature:80

°

C

to 96

°

C(176

°

F to 205

°

F).

•

The standard value during idling should be 10Hz or
more.

•

When the engine is revved, the frequency should
increase according to the increase in engine speed.

(5) 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.

STEP 2. Replace the volume air flow sensor.
(1) Replace the volume air flow sensor.
(2) Carry out a test drive with the drive cycle pattern. Refer to,

Procedure 6

−

Other Monitor(

P.13A-5

).

(3) Check the diagnostic trouble code (DTC).

Q: Is the DTC P0102 is output?

YES : Replace the PCM. Then go to Step 3.
NO : The inspection is complete.

STEP 3. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to,

Procedure 6

−

Other Monitor(

P.13A-5

).

(2) Check the diagnostic trouble code (DTC).

Q: Is the DTC P0102 is output?

YES : Retry the troubleshooting.
NO : The inspection is complete.

AC003081 AB

16 PIN

MB991502

ACX02480

CONNECTOR : B-14

AC

VOLUME AIR
FLOW SENSOR

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-35

DTC P0103: Volume Air Flow Circuit High Input

AK000459

1 2 3 4 5 6 7

42 43
48 49 50 51 52 53 54 55 56 57

46

45

44

58 59

60 61 62 63

64 65 66

2

3 4

5 6

7 8

9

11 12 13 14 15 16 17 18 19 20

30

21 22 23

24 25

26 27 28 29

3132 33

34 35

RED

RED

-

WHITE

RED

-

WHITE

47

1

41

10

RED

-

WHITE

3 4

1 2

GREEN-BL

UE

BL

ACK

WHITE-GREEN

B-14

MFI
RELAY

BATTERY

VOLUME AIR
FLOW SENSOR

5V

19

7

57

65

4

5

3

C-39
(MU803784)

C-40
(MU803781)

POWERTRAIN CONTROL
MODULE(PCM)

3

4

1

2

A-21X

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-36

CIRCUIT OPERATION

•

The volume air flow sensor power is supplied
from the MFI relay (terminal 1), and the ground is
provided on the PCM (terminal 57).

•

5-volt power is applied to the volume air flow
sensor output terminal (terminal 3) from the PCM
(terminal 65). The volume air flow sensor
generates a pulse signal when the output
terminal and ground are opened/closed (opened/
short).

TECHNICAL DESCRIPTION

•

While the engine is running, the volume air flow
sensor outputs a pulse signal which corresponds
to the volume of air flow.

•

The PCM checks whether the frequency of this
signal output by the volume air flow sensor while
the engine is running is at or above the set value.

•

When the throttle position sensor output voltage
is low, the PCM causes the power transistor to be
"ON" to send an air flow sensor reset signal to the
air flow sensor. In response to the reset signal,
the air flow sensor resets the filter circuit and
improves the ability of the air flow sensor to
measure the amount of air in a small air intake
region.

DTC SET CONDITIONS

Check Conditions

•

Throttle position sensor voltage is 2 volts or
lower.

•

Engine speed is lower than 2,000 r/min.

Judgement Criteria

•

Volume air flow sensor output frequency has
continued to be 800 Hz or higher for 2 seconds.

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

•

Volume air flow sensor failed.

•

Open or shorted volume air flow sensor circuit, or
loose connector.

•

PCM failed.

•

Air leak between volume air flow sensor and
throttle body.

DIAGNOSIS

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

ACX02480

CONNECTOR : B-14

AC

VOLUME AIR
FLOW SENSOR

AK000280

CONNECTORS : C-39, C-40

C-39 C-40

PCM

AU

AK000555AB

CONNECTOR : A-21X

MFI RELAY