Mitsubishi Eclipse. Manual - part 134

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-29

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PROBLEM SYMPTOMS TABLE (FOR YOUR INFORMATION)

Ignition switch-ST system <M/T>

31

P.13A-867

Ignition switch-ST system and transmission range switch system <A/T>

32

P.13A-873

Ignition circuit system

33

P.13A-877

A/C system

34

P.13A-887

SYMPTOMS

INSPECTION 
PROCEDURE

REFERENCE 
PAGE

ITEMS

SYMPTOM

Starting

Won't start 

The starter is used to crank the engine, but there is no combustion 
within the cylinders, and the engine won't start.

Starts up and 
dies

The engine starts, but then the engine soon stalls.

Hard starting

Engine starts after cranking a while.

Idling stability

Hunting

Engine speed doesn't remain constant; changes at idle.

Rough idle

Usually, a judgement can be based upon the movement of the 
tachometer pointer, and the vibration transmitted to the steering wheel, 
shift lever, body, etc.

Incorrect idle 
speed

The engine doesn't idle at the usual correct speed.

Engine stall (die 
out)

The engine stalls when the foot is taken from the accelerator pedal, 
regardless of whether the vehicle is moving or not. 

Engine stall 
(pass out)

The engine stalls when the accelerator pedal is depressed or while it is 
being used.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-30

Driving

Hesitation Sag

"Hesitation" is the delay in 
response of the vehicle speed 
(engine speed). This occurs when 
the accelerator is depressed in 
order to accelerate from the speed 
at which the vehicle is now 
traveling, or a temporary drop in 
vehicle speed (engine speed) 
during such acceleration. 
Serious hesitation is called "sag".

Poor 
acceleration

Poor acceleration is inability to obtain an acceleration corresponding to 
the degree of throttle opening, even though acceleration is smooth or 
the inability to reach maximum speed.

Stumble

Engine speed increase is delayed 
when the accelerator pedal is 
initially depressed for acceleration. 

Shock

The feeling of a comparatively large impact or vibration when the 
engine is accelerated or decelerated. 

Surge

This is slight acceleration and deceleration feel usually felt during 
steady, light throttle cruise. Most notable under light loads.

Knocking

A sharp sound during driving like a hammer striking the cylinder walls.

Stopping

Dieseling (run 
on) 

The condition in which the engine continues to run after the ignition 
switch is turned to the "LOCK" (OFF) position. Also called "dieseling".

ITEMS

SYMPTOM

AKX01361

VEHICLE
SPEED

TIME

NORMAL

HESITATION

SAG

INITIAL
ACCELE-
RATOR
PEDAL
DEPRE-
SSION

AKX01361AB

AKX01362

VEHICLE
SPEED

TIME

NORMAL

STUMBLE

INITIAL
ACCEL-
ERATOR
PEDAL 
DEP-
RESSION

IDLING

AC

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-31

DIAGNOSTIC TROUBLE CODE PROCEDURES

DTC P0101: Volume Airflow Circuit Range/Performance Problem

AK300331

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

GREEN-BL

UE

BROWN

WHITE-GREEN

82

78

81

80

89 90 91 92

79

87

71

74

73

72

76

75

77

85

88

83 84

86

B-14

MFI
RELAY

BATTERY

Volume Airflow Sensor Circuit

VOLUME 
AIRFLOW 
SENSOR

5 V

19 <M/T>*1
19 <A/T>*4

7

40 <M/T>*2
16 <A/T>*4

90 <M/T>*3
65 <A/T>*5

4

5

3

C-60 <M/T>
(MU803772)

C-50 <A/T>
(MU803784)

C-54 <A/T>
(MU803781)

NOTE
*1: ECM connector C-49 <M/T>
*2: ECM connector C-53 <M/T>
*3: ECM connector C-60 <M/T>
*4: PCM connector C-50 <A/T>
*5: PCM connector C-54 <A/T>

ENGINE CONTROL
MODULE (ECM) <M/T>
OR
POWERTRAIN CONTROL
MODULE (PCM) <A/T>

1

2

4

3

1

14

4

19

5

22

6

17

8

15

9

18

7

20

16

2

13

12

23 24 25 26

21

3

C-49 <M/T>
(MU803773)

10 11

C-53 <M/T>
(MU803771)

34

33

32

36

35

37

42

45

31

39

38

46

40 41

43 44

3 4

1 2

A-18X

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-32

.

CIRCUIT OPERATION

• The volume airflow sensor power is supplied from 

the MFI relay (terminal No. 4), and the ground is 
provided on the ECM (terminal No. 40) <M/T> or 
PCM (terminal No. 16) <A/T>.

• 5-volt power is applied to the volume airflow sen-

sor output terminal (terminal No. 3) from the ECM 
(terminal No. 90) <M/T> or PCM (terminal No. 65) 
<A/T>. The volume airflow 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 airflow 

sensor outputs a pulse signal which corresponds 
to the volume of air flow.

• The ECM <M/T> or PCM <A/T> checks whether 

the frequency of this signal output by the volume 
airflow sensor while the engine is running is at or 
above the set value.

• When the throttle position sensor output voltage 

is low, the ECM <M/T> or PCM <A/T> causes the 
power transistor to be "ON" to send an volume 
airflow sensor reset signal to the volume airflow 
sensor. In response to the reset signal, the vol-
ume airflow sensor resets the filter circuit and 
improves the ability of the volume airflow sensor 
to measure the amount of air in a small air intake 
region.

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DESCRIPTIONS OF MONITOR METHODS
Compare load value with volume airflow sensor out-

put frequency.

.

MONITOR EXECUTION
Continuous

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MONITOR EXECUTION CONDITIONS (Other 
monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Not applicable

Sensor (The sensor below is determined to be 

normal)

• Throttle position sensor

.

AK300121

MFI RELAY

CONNECTOR: A-18X

AB

A-18X

AK300053

CONNECTOR: B-14

VOLUME AIRFLOW 
SENSOR

AB

B-14 (B)

AK300060

ECM

CONNECTORS: C-49, C-53, C-60 <M/T>

AM

C-53 (G) C-60 (G)

C-49 (G)

AK300060

PCM

CONNECTORS: C-50, C-54 <A/T>

AO

C-54 (GR)

C-50 (GR)