Mitsubishi Outlander (2003+). Manual - part 71

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MFI)

13A-147

Code No. P0420: Catalyst malfunction

FUNCTION

œ

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

œ

The engine-ECU compares the output of the front 
and rear heated oxygen sensor signals.

TROUBLE JUDGMENT

Check Conditions

œ

Engine speed: 3,000 r/min or less.

œ

During the driving.

œ

During the air-fuel ratio feedback control.

Judgment Criterion

œ

When the output frequency ratio of the oxygen 
sensor (rear) vs. The oxygen sensor (front) is 0.8 
or more on the average for 12 seconds.

PROBABLE CAUSE

œ

Catalytic converter deteriorated

œ

Failed oxygen sensor (front)

œ

Failed oxygen sensor (rear)

œ

Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1.Check for leakage of exhaust emission 
from exhaust manifold.

Q: Is the check result normal?

YES : 

Go to Step 2 .

NO : 

Repair.

STEP 2.MUT-II data list

œ

Refer to Data list reference table 

3

13A



.

a. Item 11: Oxygen sensor (front)
b. Item 59: Oxygen sensor (rear)

Q: Is the check result normal?

YES : 

 Go to Step 3 .

NO : 

Perform the diagnosis code classified check 
procedure for the sensor that has shown an 
abnormal data valve (Refer to Inspection 
Chart for Diagnosis Codes 

3

13A



).

STEP 3.MUT-II data list

a. Item 11: Oxygen sensor (front)

OK: 0 

-

 0.4 and 0.6 

-

 1.0 volt should alternate 

15 times or more within 10 seconds (engine 
speed at 2,000 r/min).

Q: Is the check result normal?

YES : 

 Go to Step 4 .

NO : 

Replace the oxygen sensor (front).

STEP 4.Replace the oxygen sensor (rear).

œ

After replacing the oxygen sensor (rear), re-
check the trouble symptoms.

Q: Is the check result normal?

YES : 

Go to Step 5 .

NO : 

Check end.

STEP 5.Replace the catalytic converter.

œ

After replacing the catalytic converter, re-check 
the trouble symptoms.

Q: Is the check result normal?

YES : 

 Replacing engine-ECU.

NO : 

Check end.

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MFI)

13A-148

Code No. P0443: Purge Control Solenoid Valve System

OPERATION

œ

Power is supplied to the purge control solenoid 
valve (terminal No. 2) from the engine control 
relay (terminal No. 1).

œ

The engine-ECU (terminal No. 9) makes the 
power transistor in the unit be in "ON" position, 
and that makes currents go on the purge control 
solenoid valve (terminal No. 1).

1

2

3

4

AK300282

2

1

1

14

4

19

5

22

6

17

8

15

9

18

7

20

16

2

13

12

23 24 25 26

21

3

10 11

AB

Engine control relay

B-17X

1

2

9

Engine-ECU

     B-101
(MU802779)

Purge control solenoid valve

1

2

Purge control solenoid valve circuit

W-B

W-B

R

BR

Battery

4

3

Wire colour code
B: Black  LG: Light green  G: Green   L: Blue   W: White   Y: Yellow   SB: Sky blue   BR: Brown    O: Orange   GR: Gray
R: Red   P: Pink   V: Violet

C-134

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MFI)

13A-149

FUNCTION

œ

In response to a signal from the engine-ECU, the 
purge control solenoid valve controls the flow rate 
of the purge air to be introduced into the surge 
tank.

TROUBLE JUDGMENT

Check Conditions

œ

Ignition switch: ON

œ

The battery voltage is 10 V or more.

Judgment Criteria

œ

The surge voltage (system voltage + 2 V) of sole-
noid coil is not detected when the purge control 
solenoid valve is turned in OFF position from ON.

œ

The battery voltage is 10 V or more.

PROBABLE CAUSE

œ

Failed purge control solenoid valve

œ

Open/short circuit in purge control solenoid value 
circuit or loose connector contact

œ

Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. MUT-II actuator test

œ

Item 08: Purge control solenoid valve

OK: Operating sound can be heard and the 
valve vibrates

Q: Is the check result normal?

YES : 

Intermittent malfunction (Refer to GROUP 

00 

-

 How to Use 

Troubleshooting/Inspection Service Points 

3

00



).

NO : 

Go to Step 2 .

STEP 2. Connector check: B-101 purge control 
solenoid valve connector

Q: Is the check result normal?

YES : 

Go to Step 3 .

NO : 

Repair.

STEP 3: Measure resistance at B-101 purge 
control solenoid valve connector.

œ

Disconnect connector, and measure at solenoid 
valve side.

œ

Resistance between terminal No. 1 and No. 2.

OK: 30 

-

 34 

W

 (at 20

•

C)

Q: Is the check result normal?

YES : 

Go to Step 4 .

NO : 

Replace purge control solenoid valve.

STEP 4. Measure voltage at B-101 purge control 
solenoid valve connector.

œ

Disconnect connector, and measure at harness 
side.

œ

Ignition switch: ON

œ

Voltage between terminal No. 2 and earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 6 .

NO : 

Go to Step 5 .

1

2

AK300283AB

Harness side
connector

B-101 (B)

Connector: B-101

1

2

AK300283AB

Harness side
connector

B-101 (B)

Connector: B-101

1

2

AK300283AB

Harness side
connector

B-101 (B)

Connector: B-101

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MFI)

13A-150

STEP 5. Connector check: B-17X engine control 
relay connector

Q: Is the check result normal?

YES : 

Check and repair harness between B-101 

(terminal No. 2) purge control solenoid valve 
connector and B-17X (terminal No. 1) 
engine control relay connector.

œ

Check power line for open/short 
circuit.

NO : 

Repair.

STEP 6. Measure voltage at C-134 engine-ECU 
connector.

œ

Disconnect connector, and measure at harness 
side.

œ

Ignition switch: ON

œ

Voltage between terminal No. 9 and earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 8 .

NO : 

Go to Step 7 .

AK300255

2

1

3

4

Relay box’s
triangle marks

AB

CONNECTOR: B-17X

B-17X

Harness side
connector

1

2

AK300283AB

Harness side
connector

B-101 (B)

Connector: B-101

AK300257

1

14

4

19

5

22

6

17

8

15

9

18

7

20

16

2

13 12

23

24

25

26

21

3

10

11

AB

CONNECTOR: C-134

C-134

Harness side connector