Mitsubishi Eclipse. Manual - part 431

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-267

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 right 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 right 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 right bank heated oxygen sen-

sor (front) heater circuit harness damage, or con-
nector damage.

• Open circuit in right bank heated oxygen sensor 

(front) heater.

• ECM failed. <M/T>

• PCM failed. <A/T>

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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-268

DIAGNOSIS

Required Special Tool:

• MD998464: Test Harness

STEP 1. Check connector B-27at the right bank heated 
oxygen sensor (front) for damage.
Q: Is the connector in good condition?

YES : Go to Step 2.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 12.

AK300409

1

2

3

4

RIGHT BANK 
HEATED OXYGEN
SENSOR (FRONT)

AB

B-27 (B)

CONNECTOR: B-27

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-269

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

connector B-27 and connect test harness special tool, 
MD998464, to the connector on the right bank heated 
oxygen (front) sensor side.

(2) Measure the resistance between heated oxygen sensor 

connector terminal No. 1 (red clip) and terminal No. 3 (blue 
clip).

Standard value: 4.5 

− 8.0 ohms [at 20°C (68°F)]

Q: Is the resistance between 4.5 and 8.0 ohms?

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

Then go to Step 12.

AK300409

1

2

3

4

RIGHT BANK 
HEATED OXYGEN
SENSOR (FRONT)

AB

B-27 (B)

CONNECTOR: B-27

HARNESS CONNECTOR:
COMPONENT SIDE

AKX01624

HEATED
OXYGEN
SENSOR
EQUIPMENT
SIDE
CONNECTOR

MD998464

BLUE

RED

AC

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-270

STEP 3. Check the power supply voltage at right bank 
heated oxygen sensor (front) harness side connector B-27.
(1) Disconnect the connector B-27 and measure at the harness 

side.

(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 1 and ground.

• Voltage should be battery positive voltage.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts) 

present?
YES : Go to Step 5.
NO :  Go to Step 4.

STEP 4. Check connector A-18X at the MFI relay for 
damage.
Q: Is the connector in good condition?

YES : Repair harness wire between MFI relay connector 

A-18X (terminal No. 4) and right bank heated oxygen 
sensor (front) connector B-27 (terminal No. 1) 
because of open circuit or short circuit to ground Then 
go to Step 12.

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

Connector Inspection 

P.00E-2

. Then go to Step 12.

AK300409

1

2

3

4

RIGHT BANK 
HEATED OXYGEN
SENSOR (FRONT)

AB

B-27 (B)

CONNECTOR: B-27

HARNESS CONNECTOR:
COMPONENT SIDE

AKX01498 AU

2

1

4

3

B-27 HERNESS 
CONNECTOR: 
COMPONENT SIDE

AK300454

2

1

3

4

CONNECTOR: A-18X

AB

A-18X

HARNESS CONNECTOR:
COMPONENT SIDE