Mitsubishi Lancer Evolution X. Manual - part 379

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-581

Judgment Criterion

• For 0.76 second, the difference between the volu-

metric efficiency estimated by the throttle position
sensor (main) and the volumetric efficiency esti-
mated by the throttle position sensor (sub) is 8.8
percent or less.

FAIL-SAFE AND BACKUP FUNCTION

• Fuel control is carried out using throttle opening

degree and engine speed in accordance with pre-
set map.

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:)

• Mass airflow sensor system failed.
• ECM failed.

DIAGNOSIS

Required Special Tools:

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

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

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 P1235 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)

13A-582

STEP 2. Using scan tool MB991958, check data list item 10:
Mass Airflow Sensor.
(1) Start the engine and run at idle.
(2) Set scan tool MB991958 to the data reading mode for item

10, Mass Airflow Sensor.

(3) 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

1,350 and 1,670 millivolts.

• When the engine is revved, the mass airflow rate should

increase according to the increase in engine speed.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?

YES : Go to Step 3.
NO : Refer to, DTC P0101 − Mass Airflow Circuit

Range/Performance Problem

P.13A-126

, DTC P0102

− Mass Airflow Circuit Low Input

P.13A-132

, DTC

P0103 − Mass Airflow Circuit High Input

P.13A-139

STEP 3. Check the trouble symptoms.
(1) Carry out a test drive with the drive cycle pattern. Refer to

Diagnostic Function − OBD-II Drive Cycle − Pattern 16

P.13A-9

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P1235 set?

YES : 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

. Then go to Step 4.

NO : 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

STEP 4. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to

Diagnostic Function − OBD-II Drive Cycle − Pattern 16

P.13A-9

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P1235 set?

YES : Retry the troubleshooting.
NO : The inspection is complete.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-583

DTC P1236: A/D Converter

TECHNICAL DESCRIPTION

Monitors whether input voltage from the accelerator
pedal position sensor (sub) is normally converted
into a digital signal in the ECM.

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

DTC SET CONDITIONS

Check Condition

• Ignition switch is "ON" position.

Judgment Criterion

• When the input voltage from the accelerator

pedal position sensor (sub) is periodically 0 V for
0.45 second, the digital value of the input voltage
indicates 0.2 V or more.

FAIL-SAFE AND BACKUP FUNCTION

• Throttle opening degree position is in default

position.

OBD-II DRIVE CYCLE PATTERN

• None.

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

• ECM failed.

DIAGNOSIS

Required Special Tools:

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

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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-584

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

CAUTION

YES : 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

NO : 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

DTC P1237: Accelerator Pedal Position Sensor Plausibility

TECHNICAL DESCRIPTION

Compare the output value of the accelerator pedal
position sensor (main) with that of the accelerator
pedal position sensor (sub).

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

AC608435

Data link connector

MB991827

MB991824

MB991910

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