Mitsubishi Galant 9G. Manual — part 651

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-46

DTC P0101: Mass Airflow Circuit Range/Performance Problem

CAUTION

If DTC P0101 has been set, TCL related DTC
U1120 is also set. After P0101 has been diag-
nosed, don't forget to erase DTC U1120.

1

2

3

4

1

2

3 4

52

51

53 54 55 56

57

58 59 60 61 62

63

64 65 66 67 68 69

70

71 72 73 74 75

76

77 78 79 80 81 82

83

100

99

92

91

93 94 95

96 97 98

101 102 103 104

105 106 107 108

109 110 111 112 113

AK400876

RED

WHITE-GREEN

BLA

C

K

RED-

WHITE

RED-

WHITE

B-10

B-17X

MFI RELAY

BATTERY

MASS AIRFLOW
SENSOR

HEAT
SENSITIZING
RESISTANCE

POWERTRAIN CONTROL
MODULE (PCM)

108

3

69

2

1

2

4

4

3

Mass Airflow Sensor Circuit

B-21

B-22

TO PCM

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-47

.

CIRCUIT OPERATION

• The mass airflow sensor power is supplied from

the MFI relay (terminal No. 4), and the ground is
provided on the PCM (terminal No. 69).

• A voltage that is according to the mass airflow

rate is sent to the PCM (terminal No. 108) from
the mass airflow sensor output terminal (terminal
No. 3).

.

TECHNICAL DESCRIPTION

• While the engine is running, the mass airflow

sensor outputs voltage which corresponds to the
mass airflow rate.

• The PCM checks whether the voltage output by

the mass airflow sensor while the engine is run-
ning is within a specified range.

.

DESCRIPTIONS OF MONITOR METHODS

Compare load value with mass airflow sensor output

voltage.

.

MONITOR EXECUTION

Continuous

.

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

.

AK303802AB

CONNECTOR: B-10

MASS AIRFLOW SENSOR
(WITH BUILT-IN INTAKE AIR
TEMPERATURE SENSOR)

B-10 (GR)

AK303013

CONNECTORS: B-21, B-22

PCM

AB

AIR CLEANER

B-22 (B)

B-21 (B)

AK303803AB

CONNECTOR: B-17X

MFI RELAY

B-17X

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-48

DTC SET CONDITIONS <Range/Performance problem

− high input>

Logic Flow Chart

Check Conditions

• Throttle position sensor output voltage is 1.0 volt

or lower.

• Mass airflow sensor output voltage is 4.9 volts or

lower.

Judgement Criteria

• Mass airflow sensor output voltage has continued

to be 3.5 volts or higher for 2 seconds.

.

START

END

NO

NO

YES

YES

YES

NO

MALFUNCTION

GOOD

CONTINUOUS

FAILURE FOR 2secs

OUTPUT VOLTAGE

> =3.50V

MONITORING

CONDITIONS

AK302006

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-49

DTC SET CONDITIONS <Range/Performance problem

− low input>

Logic Flow Chart

Check Conditions

• Throttle position sensor output voltage is 1.5 volts

or higher.

• Mass airflow sensor output voltage is 0.2 volt or

higher.

Judgement Criteria

• Mass airflow sensor output voltage has continued

to be 1.8 volts or lower for 2 seconds.

.

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function

− OBD-II Drive Cycle −

Procedure 6

− Other Monitor

P.13A-6

.

.

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

• Mass airflow sensor failed.

• Mass airflow sensor circuit harness damage, or

connector damage.

• PCM failed.

DIAGNOSIS

Required Special Tools:

• MB991958: Scan tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

START

END

NO

YES

YES

YES

NO

NO

MALFUNCTION

GOOD

CONTINUOUS

FAILURE FOR 2secs

OUTPUT VOLTAGE

< =1.8V

MONITORING

CONDITIONS

AK401683