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Mitsubishi Montero (2004+). Manual - part 137

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-35

DTC SET CONDITIONS <Range/Performance problem

− high input>

Logic Flow Chart

Check Conditions

• Throttle position sensor output voltage is 1.5 volts

or higher.

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

Judgement Criteria

• Volume airflow sensor output frequency has con-

tinued to be 60 Hz or lower for 2 seconds.

START

Monitoring
Conditions

END

Yes

Malfunction

Good

Output Frequency

> = 800Hz

Continuous

Failure for 2secs

AK302693

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-36

DTC SET CONDITIONS <Range/Performance problem

− low input>

Logic Flow Chart

Check Conditions

• Throttle position sensor output voltage is 2 volts

or lower.

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

Judgement Criteria

• Volume airflow sensor output frequency has con-

tinued to be 800 Hz or higher for 2 seconds.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function

− OBD-II Drive Cycle −

Procedure 6

− Other Monitor

P.13A-4

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

• Volume airflow sensor failed.

• Open or shorted volume 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

• MB991911: Main Harness B

START

MONITORING
CONDITIONS

END

YES

MALFUNCTION

GOOD

OUTPUT FREQUENCY

< =60Hz

CONTINUOUS

FAILURE FOR 2 secs

AK302918

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-37

STEP 1. Using scan tool MB991958, check data list item 12:
Volume 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

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 reset signal 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. 7 and ground by

backprobing.

• Voltage should be between 6.0 and 9.0 volts.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 6.0 and 9.0 volts?

YES : Go to Step 5.
NO : Go to Step 3.

AK302970

MB991911

MB991824

MB991827

AK200937

HARNESS
CONNECTOR:
COMPONENT SIDE

CONNECTOR: B-48

B-48(B)

AKX01515

6 7

1 2 3 4 5

AKX01515

B-48 HARNESS
CONNECTOR:
HARNESS SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-38

STEP 3. Check connector B-48 at volume airflow sensor
and connector D-133 at PCM for damage.
Q: Is the connector in good condition?

YES : Go to Step 4.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 9.

AK200937

HARNESS
CONNECTOR:
COMPONENT SIDE

CONNECTOR: B-48

B-48(B)

AK200939

CONNECTOR: D-133

HARNESS CONNECTOR:
COMPONENT SIDE

PCM

D-133(GR)

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