Mitsubishi Eclipse. Manual — part 471

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-427

.

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the ECM (ter-
minal No. 73) <M/T> or PCM (terminal No. 73)
<A/T> from the output terminal (terminal No. 4) of
the left bank heated oxygen sensor (rear).

• Terminal No. 2 of the left bank heated oxygen

sensor (rear) is grounded with ECM (terminal No.
49) <M/T> or PCM (terminal No. 57) <A/T>.

.

TECHNICAL DESCRIPTION

• The output signal of the left bank heated oxygen

sensor (front) is compensated by the output sig-
nal of the left bank heated oxygen sensor (rear).

• The ECM <M/T> or PCM <A/T> checks for an

open circuit in the left bank heated oxygen sensor
(rear) output line.

.

DESCRIPTIONS OF MONITOR METHODS
Left bank heated oxygen sensor (rear) output voltage

does not change during specified go/stop opera-
tions including fuel cut are repeated.

.

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 heater (front) monitor

• Heated oxygen sensor heater (rear) 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

.

AK300058

LEFT BANK
HEATED OXYGEN
SENSOR (REAR)

CONNECTOR: B-23

AB

B-23 (GR)

AK300244

CONNECTORS: C-55, C-59 <A/T>

AD

PCM

C-55 (GR)

C-59 (GR)

AK300091

CONNECTORS: C-58, C-62 <M/T>

ECM

AD

C-58 (GR)

C-62 (GR)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-428

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• Engine coolant temperature is higher than 76°C

(169

°F).

• The left bank heated oxygen sensor (front) is

active.

• The cumulative volume airflow sensor output fre-

quency is higher than 4,000 Hz.

• Repeat 3 or more times: drive

*1

, stop

*2

.

Drive

*1

:

• 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 10 seconds have

elapsed with the above mentioned condi-
tions, and more than 2 seconds have
elapsed with the fuel shut off.

Stop

*2

:

• Vehicle speed is lower than 1.5 km/h (1.0

mph) .

Judgement Criteria

• Change in the output voltage of the left bank

heated oxygen sensor (rear) is lower than 0.312
volt.
NOTE: Monitoring stops after fuel has been shut
off for more than 38 seconds.

.

OBD-ll DRIVE CYCLE PATTERN
Refer to , Diagnostic Function

− OBD-ll Drive Cycle −

Procedure 4

− Heated Oxygen Sensor Monitor

P.13B-7

.

.

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

• Left bank heated oxygen sensor (rear) failed.

END

YES

NO

NO

NO

START

MONITORING

CONDITION

YES

MALFUNCTION

GOOD

F1: COUNTER OF A DRIVING STATE.
F2: COUNTER OF A STOP STATE.

OUTPUT VOLTAGE

CHANGE < 0.313 V

GO/STOP OPERATION

FOR SPECIFIED TIMES

YES

AK301442

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-429

• ECM failed. <M/T>

• PCM failed. <A/T>

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

• MB991316: Test Harness

STEP 1. Using scan tool MB991958, check data list item 59:
Heated Oxygen Sensor Bank 2, Sensor 2 (left 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

59, Heated Oxygen Sensor Bank 2, Sensor 2 (left rear).

(4) Warm up the engine.

• After increasing the output voltage 0.15 volt or more by

the engine revving, finish it. Then confirm that the output
voltage reduces to 0.15 volt or less within 3 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

P.00-6

.

NO : Replace the left bank heated oxygen sensor (rear).

Then go to Step 2.

AK300810

AB

MB991911

16-PIN

MB991827

MB991824

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-430

STEP 2. Check the left bank heated oxygen sensor (rear).
(1) Disconnect the left bank heated oxygen sensor (rear)

connector B-23 and connect test harness special tool,
MB991316, to the connector on the left bank heated oxygen
sensor (rear) side.

(2) Warm up the engine until engine coolant 80

°C (176°F) or

higher.

CAUTION

Be very careful when connecting the jumper wires; incor-
rect connection can damage the left bank heated oxygen
sensor (rear).

(3) Use the jumper wires to connect terminal No. 1 (red clip) to

the positive battery terminal and terminal No. 3 (blue clip) to
the negative battery terminal.

(4) Connect a digital volt meter between terminal No. 2 (black

clip) and terminal No. 4 (white clip).

(5) While repeatedly revving the engine, measure the heated

oxygen sensor (rear) output voltage.

Standard value: 0.6

− 1.0 volt

Q: Is the voltage between 0.6 and 1.0 volt?

YES : Go to Step 3.
NO : Replace the left bank heated oxygen sensor (rear).

Then go to Step 4.

AK300410

1

2

3

4

LEFT BANK
HEATED OXYGEN
SENSOR (REAR)

CONNECTOR: B-23

AB

B-23 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AKX01625 AB

BLUE

JUMPER
WIRES

BLACK

RED

WHITE

MB991316