Mitsubishi Eclipse. Manual - part 519

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-619

STEP 1. Check the exhaust leaks.
Q: Are there any abnormalities?

YES : Repair it. Then go to Step 7.
NO :  Go to Step 2.

STEP 2. 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 3.
NO :  Refer to DTC P0136 

− Heated Oxygen Sensor Circuit 

(bank 1, sensor 2) 

P.13B-278

, 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-620

STEP 3. Using scan tool MB991958, check data list item 39: 
Heated Oxygen Sensor Bank 1, Sensor 1 (right front).
(1) Start the engine and run at idle.
(2) Set scan tool MB991958 to the data reading mode for item 

39, Heated Oxygen Sensor Bank 1, Sensor 1 (right front).

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

output voltage should be 0.6 to 1.0 volt.

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

YES : Go to Step 4.
NO :  Refer to DTC P0130 

− Heated Oxygen Sensor Circuit 

(bank 1, sensor 1) 

P.13B-214

, DTC P0131 

− Heated 

Oxygen Sensor Circuit Low Voltage (bank 1, sensor 
1) 

P.13B-233

, DTC P0133 

− Heated Oxygen Sensor 

Circuit Slow Response (bank 1, sensor 1) 

P.13B-248

, 

DTC P0134 

− Heated Oxygen Sensor No Activity 

Detected (bank 1, sensor 1) 

P.13B-254

.

STEP 4. Using scan tool MB991958, check data list item 39: 
Heated Oxygen Sensor Bank 1, Sensor 1 (right front).
(1) Start the engine and run at idle.
(2) Set scan tool MB991958 to the data reading mode for item 

39, Heated Oxygen Sensor Bank 1, Sensor 1 (right front).

(3) Keep the engine speed at 2,000 r/min.

• 0 − 0.4 and 0.6 − 1.0 volt should alternate 15 times or 

more within 10 seconds.

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

YES : Go to Step 5.
NO :  Replace the right bank heated oxygen sensor (front). 

Then go to Step 7.

AK300810

AB

MB991911

16-PIN

MB991827

MB991824 

AK300810

AB

MB991911

16-PIN

MB991827

MB991824 

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-621

STEP 5. 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 3 − 

Catalytic Converter Monitor 

P.13B-7

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0421 set?

YES : Replace the right bank side catalytic converter. Then 

go to Step 6.

NO :  The inspection is complete.

STEP 6. 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 3 − 

Catalytic Converter Monitor 

P.13B-7

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0421 set?

YES : Replace the ECM or PCM. Then go to Step 7.
NO :  The inspection is complete.

STEP 7. 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 3 − 

Catalytic Converter Monitor 

P.13B-7

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0421 set?

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

DTC P0431: Warm Up Catalyst Efficiency Below Threshold (bank 2)

.

TECHNICAL DESCRIPTION

• The signal from the rear heated oxygen sensor 

differs from the front heated oxygen sensor. That 
is because the catalytic converter purifies 
exhaust gas. When the catalytic converter has 
deteriorated, the signal from the front heated oxy-
gen sensor becomes similar to the rear heated 
oxygen sensor.

• The ECM <M/T> or PCM <A/T> compares the 

output of the front and rear heated oxygen sensor 
signals.

.

DTC SET CONDITIONS

Check Conditions

• Engine speed is lower than 3,000 r/min.

• The throttle valve is open.

• Volume airflow sensor output frequency is 

between 69 and 169 Hz.

• More than 3 seconds have elapsed after the 

above mentioned three conditions have been 
met.

• Intake air temperature is higher than −10°C 

(14

°F).

• Barometric pressure is higher than 76 kPa (11 

psi).

• Under the closed loop air/fuel ratio control.

• Vehicle speed is 1.5 km/h (0.93 mph) or more.

• The ECM <M/T> or PCM <A/T> monitors for this 

condition for 7 cycles of 12 second each during 
the drive cycle.

• Short-term fuel trim is higher than −30 percent 

and lower than +25 percent.

• The cumulative volume airflow sensor output fre-

quency is higher than 4,000 Hz.

Judgment Criteria

• The left bank heated oxygen sensor (rear) signal 

frequency divided by left bank heated oxygen 
sensor (front) signal frequency = 0.8 or more.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-622

.

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

• Left bank side catalytic converter deteriorated.

• Left bank heated oxygen sensor failed.

• ECM failed. <M/T>

• PCM failed. <A/T>

• Exhaust leak

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

STEP 1. Check the exhaust leaks.
Q: Are there any abnormalities?

YES : Repair it. Then go to Step 7.
NO :  Go to Step 2.

STEP 2. 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).

• 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 3.
NO :  Refer to DTC P0156 

− Heated Oxygen Sensor Circuit 

(bank 2, sensor 2) 

P.13B-393

, DTC P0157 

− Heated 

Oxygen Sensor Circuit Low Voltage (bank 2, sensor 
2) 

P.13B-412

, DTC P0158 

− Heated Oxygen Sensor 

Circuit High Voltage (bank 2, sensor 2) 

P.13B-420

, 

DTC P0159 

− Heated Oxygen

 

Sensor Circuit Slow 

Response (bank 2, sensor 2) 

P.13B-426

.

AK300810

AB

MB991911

16-PIN

MB991827

MB991824