Mitsubishi Eclipse. Manual — part 518

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-615

STEP 10. Check for harness damage between MFI relay
connector A-18X (terminal No. 4) and EGR vacuum
regulator solenoid valve connector B-31 (terminal No. 1).
Q: Is the harness wire in good condition?

YES : Go to Step 11.
NO : Repair it. Then go to Step 12.

AK300454

2

1

3

4

CONNECTOR: A-18X

AB

A-18X

HARNESS CONNECTOR:
COMPONENT SIDE

AK300436

1

2

CONNECTOR: B-31 <WITHOUT INTAKE
MANIFOLD TUNING SYSTEM>

AB

B-31 (BR)

HARNESS CONNECTOR:
COMPONENT SIDE

AK300430

1

2

CONNECTOR: B-31 <WITH INTAKE
MANIFOLD TUNING SYSTEM>

AB

B-31 (BR)

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-616

STEP 11. Check for harness damage between EGR vacuum
regulator solenoid valve connector B-31 (terminal No. 2)
and ECM connector C-51 (terminal No. 6) <M/T> or PCM
connector C-52 (terminal No. 6) <A/T>.
Q: Is the harness wire in good condition?

YES : Replace the ECM or PCM. Then go to Step 12.
NO : Repair it. Then go to Step 12.

AK300436

1

2

CONNECTOR: B-31 <WITHOUT INTAKE
MANIFOLD TUNING SYSTEM>

AB

B-31 (BR)

HARNESS CONNECTOR:
COMPONENT SIDE

AK300430

1

2

CONNECTOR: B-31 <WITH INTAKE
MANIFOLD TUNING SYSTEM>

AB

B-31 (BR)

HARNESS CONNECTOR:
COMPONENT SIDE

AK300458

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1

10

CONNECTOR: C-52 <A/T>

C-52 (GR)

AB

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-617

STEP 12. 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 − Procedure 6 −

Other Monitor

P.13B-7

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0403 set?

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

DTC P0421: Warm Up Catalyst Efficiency Below Threshold (bank 1)

.

TECHNICAL DESCRIPTION

• The signal from the rear heated oxygen sensor

differs from the front heated oxygen sensor. That
is because the catalytic converter purifies
exhaust gas. When the catalytic converter has
deteriorated, the signal from the front heated oxy-
gen sensor becomes similar to the rear heated
oxygen sensor.

• The ECM <M/T> or PCM <A/T> compares the

output of the front and rear heated oxygen sensor
signals.

.

DESCRIPTIONS OF MONITOR METHODS
Front and rear oxygen sensor rich/lean switching fre-

quencies are nearly equal.

.

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)

• Heated oxygen sensor (front) monitor

• Heated oxygen sensor (rear) monitor

• Oxygen sensor heater (front)

• Oxygen sensor heater (rear)

• Misfire monitor

• Fuel system monitor

• Air/fuel ratio feedback monitor

Sensor (The sensor below is determined to be

normal)

• Volume airflow sensor

• Engine coolant temperature sensor

• Intake air temperature sensor

• Barometric pressure sensor

• Throttle position sensor

.

AK300443

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30

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1

10

CONNECTOR: C-51 <M/T>

C-51 (GR)

AB

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-618

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• Engine speed is lower than 3,000 r/min.

• The throttle valve is open.

• Volume airflow sensor output frequency is

between 69 and 169 Hz.

• More than 3 seconds have elapsed after the

above mentioned three conditions have been
met.

• Intake air temperature is higher than −10°C

(14

°F).

• Barometric pressure is higher than 76 kPa (11

psi).

• Under the closed loop air/fuel ratio control.

• Vehicle speed is 1.5 km/h (0.93 mph) or more.

• The ECM <M/T> or PCM <A/T> monitors for this

condition for 7 cycles of 12 second each during
the drive cycle.

• Short-term fuel trim is higher than −30 percent

and lower than +25 percent.

• The cumulative volume airflow sensor output fre-

quency is higher than 4,000 Hz.

Judgment Criteria

• The right bank heated oxygen sensor (rear) sig-

nal frequency divided by right bank heated oxy-
gen sensor (front) signal frequency = 0.8 or more.

.

OBD-ll DRIVE CYCLE PATTERN
Refer to , Diagnostic Function

− OBD-ll Drive Cycle −

Procedure 3

− Catalytic Converter Monitor

P.13B-7

.

.

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

• Right bank side catalytic converter deteriorated.

• Right bank heated oxygen sensor failed.

• ECM failed. <M/T>

• PCM failed. <A/T>

• Exhaust leak

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

START

MONITORING

CONDITIONS

Rf > R0

MALFUNCTION

GOOD

END

NO

NO

YES

YES

CALCULATE AVERAGE FREQUENCY

RATIO (Rf = Fr/Ff) OF SPECIFIED TIMES

R0: AVERAGE THRESHOLD VALUE.
R1: REAL TIME THRESHOLD VALUE.

AK204058