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Mitsubishi Evolution X. Manual - part 284

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-113

DTC P0102: Mass Airflow Circuit Low Input

AK704233

71 72 73 74 75 76 77 78 79 80 81 82

83 84 85 86 87 88 89 90 91 92 93 94

95 96 97 98 99

100 101 102 103 104

112 113 114

109

108

107

110 111

115 116

106

105

118

117

3 4

MASS AIRFLOW SENSOR CIRCUIT

MASS AIRFLOW SENSOR

HEAT
SENSITIZING
RESISTANCE

BLUE

A-07

(MU805110)

20A

WHITE

A-34X

B-10

FUSIBLE LINK

OFF

RELAY BOX
(ENGINE COMPARTMENT)

ENGINE
CONTROL
MODULE

TO ECM

MFI
RELAY

BLA

CK-BLUE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-114

CIRCUIT OPERATION

• The mass airflow sensor power is supplied from

the MFI relay (terminal No. 2), and the ground is
provided on the ECM (terminal No. 88).

• A voltage that is according to the mass airflow

rate is sent to the ECM (terminal No. 87) 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 ECM 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

Mass airflow sensor output voltage is out of specified

range.

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)

• Not applicable

AK704234

Connector: A-07

Mass airflow sensor

A-07 (GR)

AK704226

Connector: A-34X

MFI relay

A-34X

AK704235 AB

Connector: B-10

ECM

B-10 (GR)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-115

DTC SET CONDITIONS

Logic Flow Chart

Check Condition

• 3 seconds or more have passed since the ignition

switch was turned to "ON" position.

Judgement Criterion

• Mass airflow sensor output voltage has continued

to be lower than 0.2 volt (corresponding to an air
flow rate of 0 g/sec) for 2 seconds.

FAIL-SAFE AND BACKUP FUNCTION

• None

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function

− OBD-II Drive Cycle −

Pattern 23

P.13A-9

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

• Mass airflow sensor failed.

• Open or shorted mass airflow sensor circuit, or

connector damage.

• ECM failed.

End

Malfunction

Output voltage

< 0.2V

Output voltage

> 4.9V

Good

AK604310

Start

Yes

Continuous
failure for 2secs

Monitoring
conditions

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-116

DIAGNOSIS

Required Special Tools:

• MB991958: Scan tool (M.U.T.-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

• MB992110: Power Plant ECU Check Harness

STEP 1. Using scan tool MB991958, check data list item 10:
Mass Airflow 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) Start the engine and run at idle.
(3) Set scan tool MB991958 to the data reading mode for item

10, Mass Airflow Sensor.

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

° C

to 95

° C (176° F to 203° F).

• The standard value during idling should be between

1,300 and 1,650 millivolts.

• When the engine is revved, the mass airflow rate 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

− How to

Cope with Intermittent Malfunctions

P.00-15

NO : Go to Step 2.

STEP 2. Check harness connector A-07 at mass airflow
sensor for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 3.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 10.

STEP 3. Measure the power supply voltage at mass airflow
sensor harness side connector A-07.
(1) Disconnect the connector A-07 and measure at the harness

side.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal No. 2 and ground.

• Voltage should be battery positive voltage.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts)

present?
YES : Go to Step 5.
NO : Go to Step 4.

AC608435

Data link connector

MB991827

MB991824

MB991910

AK704237

2 1

A-07 harness
connector:
component side

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