Mitsubishi Lancer Evolution X. Manual - part 321

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-349

STEP 6. Using scan tool MB991958, check data list item 15: 
Throttle Position Sensor (sub).
(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 

15, Throttle Position Sensor (sub).

• Output voltage should be 4.0 volts or more when the 

throttle valve is fully closed with your finger.

• Output voltage should be 1.0 volt or less when the throt-

tle 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

.

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

register the ID code. Refer to GROUP 42B, ID Code 
Registration Necessity Judgment Table <Vehicles 
with KOS> 

P.42B-11

 or GROUP 42C, ID Codes 

Registration Judgment Table <Vehicles with WCM> 

P.42C-9

. Then go to Step 8.

STEP 7. Replace the throttle body assembly.
(1) Replace the throttle body assembly.
(2) Turn the ignition switch to the "ON" position.
(3) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P0223 set?

YES : Replace the ECM. When the ECM is replaced, 

register the ID code. Refer to GROUP 42B, ID Code 
Registration Necessity Judgment Table <Vehicles 
with KOS> 

P.42B-11

 or GROUP 42C, ID Codes 

Registration Judgment Table <Vehicles with WCM> 

P.42C-9

. Then go to Step 8.

NO :  The inspection is complete.

STEP 8. 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 P0223 set?

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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-350

DTC P0234: Turbocharger Wastegate System Malfunction

.

TECHNICAL DESCRIPTION

• The ECM checks that the engine is not over-

charged by always monitoring intake air volume.

• The ECM protects the engine by shutting off fuel 

when an overcharged condition is detected.

.

DESCRIPTIONS OF MONITOR METHODS

It detects overcharging failure by monitoring intake 
air volume.

.

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)

• Turbocharger wastegate solenoid monitor

Sensor (The sensor below is determined to be 

normal)

• Mass airflow sensor
• Intake air temperature sensor
• Barometric pressure sensor
• Throttle position sensor

.

DTC SET CONDITIONS

Logic Flow Chart

.

Malfunction

Load value > 240 - 270%

Start

Yes

Yes

No

No

Continuous

failure for 1sec

End

Good

AK801251

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-351

Check Condition, Judgement Criterion

• Volumetric efficiency is higher than 240 − 270 per-

cent.

.

FAIL-SAFE AND BACKUP FUNCTION

• Fuel is cut in abnormal engine overboost condi-

tion.

.

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function − OBD-II Drive Cycle − 

Pattern 17.

.

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

• Turbocharger wastegate actuator failed.
• Charging pressure control system failed.
• ECM failed.

DIAGNOSIS

STEP 1. Check the intake charge pressure.
Refer to GROUP 15, On-vehicle Service − Intake Charge Pres-

sure Check 

P.15-5

.

Q: Are there any abnormalities?

YES : Repair or replace it. Then go to Step 3.
NO :  Go to Step 2.

STEP 2. Check the charge pressure control system.
Refer to GROUP 15, On-vehicle Service − Intake Charge Pres-

sure Control System Check 

P.15-7

.

Q: Are there any abnormalities?

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

STEP 3. Test the OBD-II drive cycle.
(1) Carry out test drive with the drive cycle pattern. Refer to 

Diagnostic Function − OBD-II Drive Cycle − Pattern 17 

P.13A-9

.

(2) Check the diagnostic trouble code (DTC).
Q: Is the DTC P0234 set?

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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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DTC P0243: Turbocharger Wastegate Solenoid 1 Circuit

AK704405

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2

1

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3

11

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20

2

1

A-10

A-13

B-09

20A

WHITE

WHITE

BLA

CK-

BLUE

BLA

CK-

BLUE

WHITE

A-34X

4

3

1

2

22

36

FUSIBLE LINK

OFF

ON

AB

RELAY BOX
(ENGINE COMPARTMENT)

ENGINE
CONTROL
MODULE

MFI
RELAY

TO ECM

TURBOCHARGER WASTEGATE SOLENOID 1 CIRCUIT

TURBOCHARGER
WASTEGATE SOLENOID 1