Mitsubishi Eclipse. Manual - part 459

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-379

STEP 11. Check the fuel pressure.
Refer to On-vehicle Service 

− Fuel Pressure Test 

P.13B-1106

.

Q: Is the fuel pressure normal?

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

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 P0154 set?

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

AK300443

2

3

4

5

6

7

8

9

11

12

13

14

15

16

17

18

19

20

30

21

22

23

24

25

26

27

28

29

31

32

33

34

35

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-380

DTC P0155: Heated Oxygen Sensor Heater Circuit (bank 2, sensor 1)

AK101601

3 4

1 2

RED

-

WHITE

RED

-

WHITE

RED

-

WHITE

RED

BROWN-

WHITE

BATTERY

1

2

4

3

LEFT BANK HEATED
OXYGEN SENSOR (FRONT)

     B-24
MU802605

1

2

3

4

TO ECM
OR PCM

TO ECM
OR PCM

ENGINE CONTROL
MODULE (ECM) <M/T>
OR
POWERTRAIN CONTROL
MODULE (PCM) <A/T>

3

MFI
RELAY

C-51 <M/T>, C-52 <A/T>
         (MU803784)

2

3 4

5 6

7 8

9

11 12 13 14 15 16 17 18 19 20

30

21 22 23

24 25

26 27 28 29

3132 33

34 35

1

10

Left Bank Heated Oxygen Sensor (front) Heater Circuit

3 4

1 2

A-18X

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-381

.

CIRCUIT OPERATION

• Power is supplied from the MFI relay (terminal 

No. 4) to the left bank heated oxygen sensor 
(front) heater.

• The ECM (terminal No. 3) <M/T> or PCM (termi-

nal No. 3) <A/T> controls continuity to the left 
bank heated oxygen sensor (front) heater by 
turning the power transistor in the ECM <M/T> or 
PCM <A/T> "ON" and "OFF".

.

TECHNICAL DESCRIPTION

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

the heater current is within a specified range 
when the heater is energized.

.

DESCRIPTIONS OF MONITOR METHODS
Left bank heated oxygen sensor heater (front) cur-

rent is out of specified range when engine coolant 
temperature is over 20

°C (68°F).

.

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)

• Not applicable

Sensor (The sensor below is determined to be 

normal)

• Engine coolant temperature sensor

.

AK300061

LEFT BANK 
HEATED OXYGEN
SENSOR (FRONT)

CONNECTOR: B-24

AB

B-24 (B)

AK300121

MFI RELAY

CONNECTOR: A-18X

AB

A-18X

AK300244

CONNECTOR: C-52 <A/T>

AC

PCM

C-52 (GR)

AK300091

CONNECTOR: C-51 <M/T>

ECM

AF

C-51 (GR)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-382

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• 60 seconds have elapsed from the start of the 

previous monitoring.

• Engine coolant temperature is higher than 20°C 

(68

°F).

• While the left bank heated oxygen sensor (front) 

heater is on.

• Battery positive voltage is at between 11 and 16.5 

volts.

Judgment Criteria

• Heater current of the left bank heated oxygen 

sensor (front) heater has continued to be lower 
than 0.16 ampere or higher than 7.5 ampere for 4 
seconds.

.

OBD-ll DRIVE CYCLE PATTERN
Refer to , Diagnostic Function 

− OBD-ll Drive Cycle − 

Procedure 6 

− Other Monitor 

P.13B-7

.

.

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

• Open or shorted left bank heated oxygen sensor 

(front) heater circuit harness damage.

• Open circuit in left bank heated oxygen sensor 

(front) heater.

• ECM failed. <M/T>

• PCM failed. <A/T>

• Connector damage.

START

END

YES

YES

YES

YES

NO

NO

NO

NO

MALFUNCTION

GOOD

CONTINUOUS

FAILURE FOR 4secs

MONITORING

CONDITIONS

CURRENT < 0.16A

CURRENT > 7.5A

AK301439