Mitsubishi 380. Manual - part 530

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-212

DTC P0150: Heated Oxygen Sensor Circuit (bank 2, sensor 1).

.

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the 
ENGINE-ECU (terminal No. 15) from the output 
terminal (terminal No. 1) of the left bank heated 
oxygen sensor (front).

• Terminal No. 2 of the left bank heated oxygen 

sensor (front) is grounded with or ENGINE-ECU 
(terminal No. 14).

.

TECHNICAL DESCRIPTION

• The left bank heated oxygen sensor (front) 

detects the concentration of oxygen in the 
exhaust gas; it converts that data to voltage, and 
sends it to the ENGINE-ECU.

• When the left bank heated oxygen sensor (front) 

begins to deteriorate, the heated oxygen sensor 
signal response deteriorates also.

• The ENGINE-ECU forcibly varies the air/fuel mix-

ture to make it leaner and richer, and checks the 
response speed of the left bank heated oxygen 
sensor (front). In addition, the ENGINE-ECU also 
checks for an open circuit in the left bank heated 
oxygen sensor (front) output line.

.

DTC SET CONDITIONS

Check Conditions

• Battery voltage < 11.02 volts

• Engine coolant temperature is higher than 80°C. 

Judgment Criteria

• Idling.

• MIL is activated after 2 Drive cycles.

• No limp home.

.

EOBD DRIVE CYCLE PATTERN

Refer to Diagnostic Function 

− EOBD Drive Cycle − 

P.13A-11

.

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

• Left bank heated oxygen sensor (front) failed.

• Short circuit in left bank heated oxygen sensor 

(front) output line to heater circuit ground line. 

• Wiring harness or connector damage.

• Refer to component locations GROUP-

70

• Refer to configuration diagrams GROUP-

80

• Refer to circuit diagrams GROUP-

90

DIAGNOSIS

Required Special Tools:

•  Diagnostic tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

AK303070

LEFT BANK

HEATED OXYGEN

SENSOR (FRONT)

CONNECTOR: B-25

B-25 (B)

AB

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-213

• MB991827: USB Cable

• MB991910: Main Harness A

• MB992044:  ENGINE-ECU Check Harness

STEP 1. Using diagnostic tool, check data list item AE: 
Heated Oxygen Sensor Bank 2, Sensor 1 (left front).

CAUTION

To prevent damage to diagnostic tool, always turn the igni-
tion switch to the "LOCK" (OFF) position before connect-
ing or disconnecting diagnostic tool .
(1) Connect diagnostic tool  to the data link connector.
(2) Start the engine and run at idle.
(3) Ensure engine is at running temperature (80

° C or higher).

(4) Set diagnostic tool  to the data reading mode for item AE, 

Heated Oxygen Sensor Bank 2, Sensor 1 (left front).

• Warm engine. When the engine is revved up and down, 

the output voltage should cycle between  0.1 to 1.0 volt.

• Warm engine. When the engine is idling, the output volt-

age should alternate between 0.1 to 0.6 -1.0 volt.

(5) Turn the ignition switch to the "LOCK" (OFF) position.

NOTE: If data list readings are consistantly low or appear 
slow to cycle( should cycle every 0.5-1.0 sec.) during check 
the sensor is likely to be malfuctioning. Ensure wiring and 
connector checks are performed prior to replacing sensor.

Q: Is the sensor operating properly?

YES : It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

− How to 

Cope with Intermittent Malfunctions 

P.00-14

.

NO :  Go to Step 2.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-214

STEP 2. Measure the sensor output voltage at 
ENGINE-ECU connector B-20 by using  ENGINE-ECU 
check harness special tool MB992044.
(1) Disconnect the ENGINE-ECU connectors and connect  

ENGINE-ECU check harness special tool MB992044 
between the separated connectors.

(2) Start the engine and run at idle.
(3) Ensure engine is at running temperature (80

° C or higher).

(4) Measure the voltage between terminal No. 15 and ground.

• Warm engine. When the engine is 2,500 r/min, the out-

put voltage should cycle between 0.1  to 0.8-1.0 volt 
alternately.

(5) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the measured voltage cycling within the specified 

range?
YES : Go to Step 6.
NO :  Go to Step 3.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

03DB208A

B-20 HARNESS 

CONNECTOR 

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-215

STEP 3. Check harness connector B-25 at left bank heated 
oxygen sensor (front) and harness connector B-20 at 
ENGINE-ECU for damage or loose terminals.
Q: Is the harness connector in good condition?

YES : Go to Step 4.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 6. 

AK303071

1

2

3

4

LEFT BANK

HEATED OXYGEN

SENSOR (FRONT)

CONNECTOR: B-25

B-25 (B)

AB

HARNESS

CONNECTOR:

COMPONENT SIDE

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER