Mitsubishi Eclipse. Manual - part 473

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-435

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 (rear) 

heater is on.

• Battery positive voltage is between 11 and 16.5 

volts.

Judgment Criteria

• Heater current of the left bank heated oxygen 

sensor (rear) heater has continued to be lower 
than 0.16 ampere or higher than 5.0 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 

(rear) heater circuit, harness damage.

• Open circuit in left bank heated oxygen sensor 

(rear) 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 > 5.0A

AK301443

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-436

DIAGNOSIS

Required Special Tool:

• MB991316: Test Harness

STEP 1. Check connector B-23 at the left bank heated 
oxygen sensor (rear) 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.

AK300410

1

2

3

4

LEFT BANK 
HEATED OXYGEN
SENSOR (REAR)

CONNECTOR: B-23

AB

B-23 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-437

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

(2) Measure the resistance between heated oxygen sensor 

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

Standard value: 11 

− 18 ohms [at 20°C (68°F)]

Q: Is the resistance between 11 and 18 ohms?

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

Then go to Step 12.

AK300410

1

2

3

4

LEFT BANK 
HEATED OXYGEN
SENSOR (REAR)

CONNECTOR: B-23

AB

B-23 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AKX01624 AB

MB991316

HEATED
OXYGEN
SENSOR
EQUIPMENT
SIDE
CONNECTOR

BLUE

RED

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-438

STEP 3. Check the power supply voltage at left bank 
heated oxygen sensor (rear) harness side connector B-23.
(1) Disconnect the connector B-23 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 left bank heated oxygen 
sensor (rear) connector B-23 (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.

AK300410

1

2

3

4

LEFT BANK 
HEATED OXYGEN
SENSOR (REAR)

CONNECTOR: B-23

AB

B-23 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AKX01496AN

B-28 HERNESS 
CONNECTOR: 
COMPONENT SIDE

1

4

3

2

AK300454

2

1

3

4

CONNECTOR: A-18X

AB

A-18X

HARNESS CONNECTOR:
COMPONENT SIDE