Mitsubishi Lancer Evolution X. Manual - part 377

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-573

STEP 2. Using scan tool MB991958, read the diagnostic
trouble code (DTC).
(1) Turn the ignition switch to the "ON" position.
(2) After the DTC has been deleted, read the DTC again.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P0657 set?

YES : Refer to DTC P0657 − Throttle actuator control motor

relay circuit malfunction

P.13A-558

NO : Replace the ECM. When the ECM is replaced,

P.42B-11

or GROUP 42C, ID Codes

Registration Judgment Table <Vehicles with WCM>

P.42C-9

DTC P1233: Throttle Position Sensor (main) Plausibility

TECHNICAL DESCRIPTION

Compare the actual measurement of volumetric effi-
ciency by a mass airflow sensor signal with volumet-
ric efficiency estimated from a throttle position
sensor (main) signal.

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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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DTC SET CONDITIONS

Logic Flow Chart

Check Conditions

• The engine speed is between 750 and 3,000

r/min. Or, the throttle position sensor (main) out-
put voltage is 3 volts or lower.

• Except while fuel is being shut off.

Judgment Criterion

• For 0.8 second, the difference between the actual

volumetric efficiency and the volumetric efficiency
estimated by the throttle position sensor (main) is
43 percent or more.

FAIL-SAFE AND BACKUP FUNCTION

• Throttle opening degree is restricted.

• Throttle opening degree position is in default

position if throttle position sensor (sub) fails.

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function − OBD-II Drive Cycle −

Pattern 16

P.13A-9

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

• Throttle position sensor (main) system failed.
• Intake system vacuum leak.
• ECM failed.

AK604351

Start

Yes

Continuous failure

for specified time

Malfunction

End

Good

Monitoring
conditions

|Ec-calculated Ec|
> specified value

Ec: load value

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-575

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.
• MB991827: USB Cable
• MB991910: Main Harness A

• MB991658: Test Harness

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) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the diagnostic trouble code other than P1233 set?

YES : Refer to, Diagnostic Trouble Code Chart

P.13A-48

NO : Go to Step 2.

AC608435

Data link connector

MB991827

MB991824

MB991910

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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STEP 2. Using scan tool MB991958, check data list item 13:
Throttle Position Sensor (main).
(1) Turn the ignition switch to the "ON" position.
(2) Detach the intake air hose at the throttle body.
(3) Disconnect the connector of the throttle position sensor.
(4) Use test harness special tool (MB991658) to connect only

terminals No. 3, No. 4, No. 5, and No. 6.

(5) Set scan tool MB991958 to the data reading mode for item

13, Throttle Position Sensor (main).

• Output voltage should be between 0.3 and 0.7 volt when

the throttle valve is fully closed with your finger.

• Output voltage should be 4.0 volts or more when the

throttle valve is fully open with your finger.

(6) 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