Mitsubishi Lancer Evolution X. Manual - part 293

 

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Mitsubishi Lancer Evolution X. Manual - part 293

 

 

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-237

DTC SET CONDITIONS
Logic Flow Chart

.

Check Conditions

• Engine coolant temperature is higher than 60° C 

(140° F).

• Engine speed is between 1,406 and 3,500 r/min.
• Volumetric efficiency is between 20 and 65 per-

cent.

• Under the closed loop air/fuel control.
• The accelerator pedal is depressed.
• Short-term fuel trim is between −

 

20 and +17 per-

cent.

• More than 3.5 seconds have elapsed after the 

above mentioned conditions have been met.

• During the drive cycle, the ECM performs moni-

toring with the accumulated total time of 10 sec-
onds, 5 times.

Judgement Criteria

• The average of the heated oxygen sensor (front) 

rich/lean switching frequency is less than 9 times 
<M/T> or 8 times <TC-SST> for the accumulated 
time of 10 seconds.

• The heated oxygen sensor (front) rich/lean 

switching frequency is less than 20 times <M/T> 
or 16 times <TC-SST> for the accumulated time 
of 10 seconds.

NOTE: If the sensor switching frequency is lower 
than the Judgement Criteria due to the M.U.T.-III 
OBD-II test Mode 

−

 HO2S Test Results, it is assumed 

that the heated oxygen sensor has deteriorated. If it 
is higher, it is assumed that the harness is damaged 
or has a short circuit.
If the heated oxygen sensor signal voltage has not 
changed even once (lean/rich) after the DTC was 
erased, the sensor switch time will display as 0 sec-
ond.

.

FAIL-SAFE AND BACKUP FUNCTION

• None

.

F0: Threshold value for average switching frequency

Start

Monitoring

conditions

Malfunction

Good

End

No

No

Yes

Yes

Ff < F0

Calculate average switching

frequency (Ff) over specified times

AK604323

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-238

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function − OBD-II Drive Cycle − 

Pattern 1 

P.13A-9

.

.

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

• Heated oxygen sensor (front) 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

• MB991658: Test Harness

STEP 1. Using scan tool MB991958, check data list item 
AC: Heated Oxygen Sensor (front).

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 

AC, Heated Oxygen Sensor (front).

(4) Warm up the engine, 2,500 r/min.

• Output voltage repeats 0.4 volt or less and 0.6 to 1.0 volt 

9 times <M/T> or 8 times <TC-SST> or more within 10 
seconds.

(5) 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 :  Go to Step 2.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-239

STEP 2. Check the heated oxygen sensor (front).
(1) Disconnect the heated oxygen sensor (front) connector 

C-34 and connect test harness special tool MB991658 to 
the connector on the heated oxygen sensor (front) side.

(2) Warm up the engine until engine coolant temperature 

reaches 80° C (176° F) or higher.

(3) Rev the engine for 5 minutes or more with the engine speed 

of 2,000 r/min.

(4) Connect a digital voltage meter between terminal No. 3 and 

terminal No. 4.

(5) Warm up the engine, 2,500 r/min 

• Output voltage repeats 0.4 volt or less and 0.6 to 1.0 volt 

9 times <M/T> or 8 times <TC-SST> or more within 10 
seconds.

CAUTION

• Be very careful when connecting the jumper wires; 

incorrect connection can damage the heated oxygen 
sensor.

• Be careful the heater can be damaged if a voltage 

beyond 8 volts is applied to the heated oxygen sensor 
heater.
NOTE: If the temperature of sensing area does not reach 
the high temperature [of approximately 400

°

C (752

°

F) or 

more] even though the heated oxygen sensor is normal, the 
output voltage would be possibly low in spite of the rich 
air/fuel ratio. Therefore, if the output voltage is low, use a 
jumper wire to connect the terminal No. 1 and the terminal 
No. 2 of the heated oxygen sensor with the positive terminal 
and the negative terminal of 8 volts power supply respec-
tively, then check again.

Q: Is the sensor operating properly?

YES : Go to Step 3.
NO :  Replace the heated oxygen sensor (front). Then go to 

Step 4.

STEP 3. Check harness connector C-34 at heated oxygen 
sensor (front) and harness connector B-09 at ECM for 
damage.
Q: Is the harness connector in good condition?

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 4.

NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 4.

AK604493AB

MB991658

Heated oxygen
sensor component
side connector

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-240

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 1 

P.13A-9

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0133 set?

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

DTC P0134: Heated Oxygen Sensor (front) Circuit No Activity Detected

.

Heated Oxygen Sensor (front) No Activity 
Detected Circuit

• Refer to DTC P0131 − Heated Oxygen Sensor 

(Front) Circuit Low Voltage 

P.13A-223

.

• Refer to DTC P0201 − Injector Circuit-cylinder 1 

P.13A-298

.

• Refer to DTC P0202 − Injector Circuit-cylinder 2 

P.13A-308

.

• Refer to DTC P0203 − Injector Circuit-cylinder 3 

P.13A-318

.

• Refer to DTC P0204 − Injector Circuit-cylinder 4 

P.13A-328

.

.

CIRCUIT OPERATION

• Refer to DTC P0131 − Heated Oxygen Sensor 

(Front) Circuit Low Voltage 

P.13A-223

.

• Refer to DTC P0201 − Injector Circuit-cylinder 1 

P.13A-298

.

• Refer to DTC P0202 − Injector Circuit-cylinder 2 

P.13A-308

.

• Refer to DTC P0203 − Injector Circuit-cylinder 3 

P.13A-318

.

• Refer to DTC P0204 − Injector Circuit-cylinder 4 

P.13A-328

.

.

TECHNICAL DESCRIPTION

• The ECM effects air/fuel ratio feedback control in 

accordance with the signals from the heated oxy-
gen sensor (front).

• If the heated oxygen sensor (front) has deterio-

rated, corrections will be made by the heated 
oxygen sensor (rear).

• DTC P0134 becomes stored in memory if a fail-

ure is detected in the above air/fuel ratio feed-
back control system.

.

DESCRIPTIONS OF MONITOR METHODS

Heated oxygen sensor (front) output voltage does 

not cross lean/rich criteria (about 0.5 volt) within 
specified period.

.

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

.

 

 

 

 

 

 

 

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