Content .. 298 299 300 301 ..

Mitsubishi Lancer Evolution X. Manual - part 300

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-265

DTC SET CONDITIONS
Logic Flow Chart

Check Conditions

• Engine coolant temperature is higher than 76° C

(169° F).

• The heated oxygen sensor (front) is active.
• The cumulative mass airflow sensor output is

1,638 g or higher.

• Repeat 1 or more times: drive

, stop

Drive

• Engine speed is higher than 1,500 r/min.
• Volumetric efficiency is higher than 40 per-

cent.

• Vehicle speed is higher than 30 km/h (19

mph).

• A total of more than 60 seconds have

elapsed with the above mentioned condi-
tions, and more than 3 seconds have
elapsed with the fuel shut off.

Stop

• Vehicle speed is lower than 1.5 km/h (1

mph).

Judgement Criterion

• Change in the output voltage of the heated oxy-

gen sensor (rear) is lower than 0.313 volt.

AK800872

Start

End

Yes

Malfunction

Good

Maximum output
voltage <= V

Monitoring conditions

Output voltage

change < V

Go/stop operation

for specified times

, V

: Threshold valve

*: See DTC SET CONDITIONS-Judgment Criterion

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-266

• The maximum output voltage of the heated oxy-

gen sensor (rear) is lower than 0.508 volt.
NOTE: Monitoring stops after fuel has been shut
off for 64 seconds or more.

FAIL-SAFE AND BACKUP FUNCTION

• None

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function − OBD-II Drive Cycle −

Pattern 12

P.13A-9

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

• Heated oxygen sensor (rear) deteriorated.
• Connector damage.
• 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, check data list item
AD: Heated Oxygen Sensor (rear).

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

AD, Heated Oxygen Sensor (rear).

a. Transaxle: 2nd speed
b. Drive with wide open throttle

c. Engine: 3,500 r/min

• The output voltages should be between 0.6 and 1.0

volt.

(4) 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 heated oxygen sensor (rear). Then go to

Step 2.

AC608435

Data link connector

MB991827

MB991824

MB991910

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-267

STEP 2. 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 12

P.13A-9

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0140 set?

YES : Refer to DTC P0137 − Heated Oxygen Sensor (rear)

Circuit Low Voltage

P.13A-246

, DTC P0138 − Heated

Oxygen Sensor (rear) Circuit High Voltage

P.13A-254

NO : The inspection is complete.

DTC P0171: System too Lean

Fuel Trim Circuit

• Refer to DTC P0201 − Injector Circuit-Cylinder 1

P.13A-298

, DTC P0202 − Injector Circuit-Cylinder

P.13A-308

, DTC P0203 − Injector Circuit-Cylin-

der 3

P.13A-318

, DTC P0204 − Injector Cir-

cuit-Cylinder 4

P.13A-328

CIRCUIT OPERATION

• Refer to DTC P0201 − Injector Circuit-Cylinder 1

P.13A-298

, DTC P0202 − Injector Circuit-Cylinder

P.13A-308

, DTC P0203 − Injector Circuit-Cylin-

der 3

P.13A-318

, DTC P0204 − Injector Cir-

cuit-Cylinder 4

P.13A-328

TECHNICAL DESCRIPTION

• If a malfunction occurs in the fuel system, the fuel

trim value becomes too large.

• The ECM checks whether the fuel trim value is

within a specified range.

DESCRIPTIONS OF MONITOR METHODS

Air/fuel learning value (long time fuel trim) and

air/fuel feedback integral value (short time fuel
trim) are too lean.

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

Sensor (The sensor below is determined to be

normal)

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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-268

DTC SET CONDITIONS

Logic Flow Chart

Check Conditions

• Engine coolant temperature is lower than 100° C

(212° F) when the engine is started.

• Intake air temperature is lower than 60° C

(140° F) when the engine is started.

• Under the closed loop air/fuel ratio control.
• Engine coolant temperature is higher than 76° C

(169° F).

• Mass airflow sensor output is 13 g/sec or more.

Judgement Criterion

• Long-term fuel trim has continued to be +12.5

percent or higher for 5 seconds.

• Short-term fuel trim has continued to be +7.0 per-

cent or higher for 5 seconds.

Check Conditions

• Engine coolant temperature is lower than 100° C

(212° F) when the engine is started.

• Intake air temperature is lower than 60° C

(140° F) when the engine is started.

• Under the closed loop air/fuel ratio control.
• Engine coolant temperature is higher than 76° C

(169° F).

• Mass airflow sensor output is less than 13 g/sec.

End

Malfunction

Good

AK604328

Start

Yes

Continuous

failure for 5secs

Monitoring
conditions

LRN

>= K0

LRN

<= K2

>= K1

<= K3

LRN

: Long-term trim

: Short-term trim

K0 : Maximum limit of long-term trim

K2 : Minimum limit of long-term trim

K1 : Maximum limit of short-term trim

K3 : Minimum limit of short-term trim

Content .. 298 299 300 301 ..