Mitsubishi Eclipse. Manual - part 428

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-255

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)

• Misfire 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

.

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• 20 seconds or more have passed since the start-

ing sequence was completed.

• Engine coolant temperature is higher than 76°C 

(169

°F).

• Engine speed is higher than 1,200 r/min.

• Volumetric efficiency is at between 30 and 95 

percent.

• Throttle position sensor output voltage is lower 

then 4 volts.

• Except while fuel is being shut off.

• Monitoring time: 30 seconds.

Judgment Criteria

• Right bank heated oxygen sensor (front) output 

voltage does not get across 0.5 volt within about 
30 seconds.

.

OBD-ll DRIVE CYCLE PATTERN
Refer to , Diagnostic Function 

− OBD-ll Drive Cycle − 

Procedure 6 

− Other Monitor 

P.13B-7

.

.

HEATED OXYGEN SENSOR (FRONT) 

OUTPUT VOLTAGE CROSSES 0.5V?

START

END

NO

NO

NO

YES

Yes

YES

MALFUNCTION

GOOD

30secs HAVE PASSED?

MONITORING

CONDITIONS

AK203999

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-256

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

• Right bank heated oxygen sensor (front) deterio-

rated.

• Open circuit in right bank heated oxygen sensor 

(front) output line.

• Open circuit in right black heated oxygen sensor 

(front) ground line.
NOTE: When the right bank heated oxygen sen-
sor (front) begins to deteriorate, the right bank 
heated oxygen sensor output voltage will deviate 
from the voltage when the sensor was new (nor-
mally 0.5 volt at stoichiometric ratio). This devia-
tion will be corrected by the right bank heated 
oxygen sensor (rear).

If the right bank heated oxygen sensor (rear) 
responds poorly because it has deteriorated, it 
will improperly correct the right bank heated oxy-
gen sensor (front). Thus, even when closed loop 
control is being effected, the fluctuation of the 
right bank heated oxygen sensor (front) output 
voltage decreases, without intersecting with 0.5 
volt. As a result, there is a possibility of DTC 
P0134 becoming registered.

• ECM failed. <M/T>

• PCM failed. <M/T>

• Harness damage.

• Connector damage.

• Fuel pressure.

• Injector damage.

• Exhaust leak.

• Intake system va.

DIAGNOSIS

Required Special Tools:

• MB991958 (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

• MD998464: Test Harness

STEP 1. Using scan tool MB991958, check data list item 69: 
Heated Oxygen Sensor Bank 1, Sensor 2 (right 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 

69, Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).

• Warming up the engine. When the engine is revved, the 

output voltage should repeat 0 volt and 0.6 to 1.0 volt 
alternately.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?

YES : Go to Step 2.
NO :  Refer to, DTC P0137 

− Heated Oxygen Sensor Circuit 

Low Voltage (bank 1, sensor 2) 

P.13B-297

, DTC 

P0138 

− Heated Oxygen Sensor Circuit High Voltage 

(bank 1, sensor 2) 

P.13B-305

, DTC P0139 

− Heated 

Oxygen Sensor Circuit Slow Response (bank 1, 
sensor 2) 

P.13B-311

.

AK300810

AB

MB991911

16-PIN

MB991827

MB991824 

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-257

STEP 2. Check the exhaust leaks.
Q: Are there any abnormalities?

YES : Repair it. Then go to Step 14.
NO :  Go to Step 3.

STEP 3. Check the intake system vacuum leak.
Q: Are there any abnormalities?

YES : Repair it. Then go to Step 14.
NO :  Go to Step 4.

STEP 4. Check connector B-27 at the right bank heated 
oxygen sensor (front) for damage.
Q: Is the connector in good condition?

YES : Go to Step 5.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 14.

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-258

STEP 5. Check the right bank heated oxygen sensor 
(front).
(1) Disconnect the 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 sensor (front) 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 right bank heated oxygen 
sensor (front).

(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 right 

bank heated oxygen sensor (front) output voltage.

Standard value: 0.6 

− 1.0 volt

Q: Is the voltage between 0.6 and 1.0 volt?

YES : Go to Step 6.
NO :  Replace the right bank heated oxygen sensor (front). 

Then go to Step 14.

STEP 6. Check connector B-48 at injector intermediate 
connector for damage.
Q: Is the connector in good condition?

YES : Go to Step 7.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 14.

AK300409

1

2

3

4

RIGHT BANK 
HEATED OXYGEN
SENSOR (FRONT)

AB

B-27 (B)

CONNECTOR: B-27

HARNESS CONNECTOR:
COMPONENT SIDE

AKX01625AC

BLUE

RED

BLACK

JUMPER
WIRES

WHITE

MD998464

AK300751

1

2

3

4

CONNECTOR: B-48

AB

B-48 (B)

HARNESS CONNECTOR:
COMPONENT SIDE