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Mitsubishi Eclipse. Manual - part 287

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-641

CIRCUIT OPERATION

• The idle air control motor power is supplied from

the MFI relay (terminal No. 4).

• The ECM (terminals No. 4, No. 5, No. 17, No. 18)

<M/T> or PCM (terminals No. 14, No. 15, No. 28,
No. 29) <A/T> drives the stepper motor by
sequentially turning "ON" the power transistors in
the ECM <M/T> or PCM <A/T> and providing
ground to the idle air control motor (terminals No.
1, No. 3, No. 4, No. 6).

TECHNICAL DESCRIPTION

• The amount of air taken in during idling is regu-

lated by the opening and closing of the servo
valve located in the air passage that bypasses
the throttle body.

• If there is a malfunction of the IAC system, the

actual engine speed will not be identical to the
target engine speed.

• The ECM <M/T> or PCM <A/T> checks the differ-

ence between the actual engine speed and the
target engine speed.

DESCRIPTIONS OF MONITOR METHODS
Difference between actual and target idle speed is

over the specified value.

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)

• Misfire monitor

• Exhaust gas recirculation (EGR) system monitor

• Fuel system monitor

Sensor (The sensor below is determined to be

normal)

• Volume airflow sensor

• Engine coolant temperature sensor

• Intake air temperature sensor

• Barometric pressure sensor

• Throttle position sensor

AK300056

CONNECTOR: B-34

IDLE AIR
CONTROL MOTOR

B-34 (B)

AK300060

ECM

CONNECTOR: C-49 <M/T>

C-49 (G)

AK300060AD

C-50 (GR)

PCM

CONNECTOR: C-50 <A/T>

AK300121

MFI RELAY

CONNECTOR: A-18X

A-18X

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-642

DTC SET CONDITIONS

Logic Flow Chart

Check Conditions

• Vehicle speed has reached 1.5 km/h (1 mph) or

more at least once.

• Under the closed loop idle speed control.

• Engine coolant temperature is higher than 77°C

(171

°F).

• Battery positive voltage is higher than 10 volts.

• Barometric pressure is higher than 76 kPa (22.4

in.Hg).

• Intake air temperature is higher than −10°C

(14

°F).

• 25 seconds have elapsed from the start of the

previous monitoring.

• Target idle air control motor position is 0 steps.

Judgment Criteria

• Actual idle speed has continued to be higher than

the target idle speed by 200 r/min (300 r/min*) or
more for 12 seconds.

*: Specs in parentheses are applicable if the max-

imum air temperature during the previous
operation was more than 45

°C (113°F).

OBD-ll DRIVE CYCLE PATTERN
Refer to Diagnostic Function

− OBD-ll Drive Cycle −

Procedure 6

− Other Monitor

P.13A-5

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

• Idle air control motor failed.

• Open or shorted idle air control motor circuit, or

harness damage, or connector damage.

• Intake system vacuum leak.

• ECM failed. <M/T>

• PCM failed. <A/T>

END

YES

MALFUNCTION

GOOD

START

CALCULATE

MONITORING

CONDITIONS

Ne = (ACTUAL-Ne) - (TARGET-Ne)

Ne: ENGINE SPEED

Ne < -100 r/min OR

> 200 r/min

HAVE 10secs PASSED?

AK204002

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-643

DIAGNOSIS

Required Special Tools:

• MB991958 (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

• MB991709: Test harness Set

STEP 1. Using scan tool MB991958, read the diagnostic
trouble code (DTC).

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) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958, read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the diagnostic trouble code other than P0507 output?

YES : Refer to, Diagnostic Trouble Code Chart

P.13A-24

NO : Go to Step 2.

STEP 2. Check the intake system vacuum leak.
Q: Are there any abnormalities?

YES : Go to Step 3.
NO : Repair or replace it. Then go to Step 14.

STEP 3. Check connector B-34 at idle air control motor 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 14.

AK300810

MB991911

16-PIN

MB991827

MB991824

AK300408

CONNECTOR: B-34

B-34 (B)

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-644

STEP 4. Check the idle air control motor coil resistance.
(1) Disconnect the idle air control motor connector B-34.

(2) Measure the resistance between idle air control motor

connector terminal No. 2 and either terminal No. 1 or
terminal No. 3.

Standard value: 28

− 33 ohms [at 20°C (68°F)]

(3) Measure the resistance between idle air control motor

connector terminal No. 5 and either terminal No. 4 or
terminal No. 6.

Standard value: 28

− 33 ohms [at 20°C (68°F)]

Q: Is the measured resistance between 28 and 33 ohms?

YES : Go to Step 5.
NO : Replace the idle air control motor. Then go to Step 14.

AK300408

CONNECTOR: B-34

B-34 (B)

HARNESS CONNECTOR:
COMPONENT SIDE

AKX01561

1 2 3
4 5 6

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