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Mitsubishi Montero (2002-2004). Manual - part 578

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-9

DTC P0102: Volume Airflow Circuit Low Input

1 2 3 4 5 6 7

3 4

1 2

RED

GREEN

WHITE-BLA

SKY B

ULE

WHITE-

BLA

WHITE-

BLA

AK201126

B-48

B-22X

MFI
RELAY

BATTERY

VOLUME AIRFLOW
SENSOR

POWERTRAIN CONTROL MODULE(PCM)

5 V

Volume Airflow Sensor Circuit

35363738394041 42 43
444546474849

50 51

5253

545556

57 58

33 34

D-133

(MU803803)

61
656667686970 717273
74757677787980 8182
8384

858687

8889

6364

D-134

(MU803804)

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-10

CIRCUIT OPERATION

• The volume airflow sensor power is supplied from

the MFI relay (terminal No. 1), and the ground is
provided on the PCM (terminal No. 88).

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

sor output terminal (terminal No. 3) from the PCM
(terminal No. 63). The volume airflow sensor gen-
erates 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 PCM 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.

DTC SET CONDITIONS

Check Conditions

• Engine speed is higher than 500 r/min.

Judgement Criteria

• Volume airflow sensor output frequency has con-

tinued to be 3.3 Hz or lower for 2 seconds.

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

• Volume airflow sensor failed.

• Open or shorted volume airflow sensor circuit, or

loose connector.

• PCM failed.

• Air leak between volume airflow sensor and throt-

tle body.

AK201039

MFI RELAY

B-22X

CONNECTOR: B-22X

AK200940AD

B-48(B)

CONNECTOR: B-48

VOLUME AIRFLOW
SENSOR

AK201038AH

CONNECTORS: D-133, D-134

PCM

D-134(GR)

D-133(GR)

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-11

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, check data list item 12:
Volume Airflow Sensor.

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting 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 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 10 Hz 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.00-6

NO : Go to Step 2.

STEP 2. Measure the power supply voltage at volume
airflow sensor connector B-48 by backprobing.
(1) Do not disconnect the connector B-48.
(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No.4 and ground by

backprobing.

• 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 3.

ACX01539

16-PIN

MB991502

AK200937

HARNESS
CONNECTOR:
COMPONENT SIDE

CONNECTOR: B-48

B-48(B)

AKX01514

6 7

1 2 3 4 5

AKX01514

B-48 HARNESS
CONNECTOR:
HARNESS SIDE

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-12

STEP 3. Measure the power supply voltage at volume
airflow sensor harness side connector B-48.
(1) Disconnect the connector B-48 and measure at the harness

side.

(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 4 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 4.
NO : Repair harness wire between MFI relay connector B-

22X (terminal No. 1) and volume airflow sensor
connector B-48 (terminal No. 4) because of open
circuit or short circuit to ground. Then go to Step 13.

STEP 4. Check connector B-48 at the volume airflow
sensor for damage.
Q: Is the connector in good condition?

YES : Repair harness wire between MFI relay connector B-

22X (terminal No. 1) and volume airflow sensor
connector B-48 (terminal No. 4) because of harness
damage. Then go to Step 13.

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

Connector Inspection

P.00E-2

. Then go to Step 13.

STEP 5. Check connector B-48 at volume airflow 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 13.

AK200937

HARNESS
CONNECTOR:
COMPONENT SIDE

CONNECTOR: B-48

B-48(B)

AKX01405

B-48 HARNESS CONNECTOR:
COMPONENT SIDE

AK200937

HARNESS
CONNECTOR:
COMPONENT SIDE

CONNECTOR: B-48

B-48(B)

AK200937

HARNESS
CONNECTOR:
COMPONENT SIDE

CONNECTOR: B-48

B-48(B)

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