Mitsubishi 380. Manual - part 528

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-204

STEP 1. Using diagnostic tool, check data list item AD: 
Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).

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 itemAD, 

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

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

output voltage should alternate between 0 and 0.6 to 1.0 
volts.

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

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 :  Replace the sensor. Then go to Step 2.

STEP 2. Test the EOBD drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− EOBD Drive Cycle − 

P.13A-11

.

(2) Check the diagnostic trouble code (DTC).

Q: Is DTC P0139 set?

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

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-205

DTC P0140: Heated Oxygen Sensor Circuit No Activity Detected (bank 1, sensor 2).

.

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the 
ENGINE-ECU (terminal No. 60) from the output 
terminal (terminal No. 1) of the right bank heated 
oxygen sensor (rear).

• Terminal No. 2 of the right bank heated oxygen 

sensor (rear) is grounded with ENGINE-ECU (ter-
minal No. 59).

• The ENGINE-ECU applies an offset voltage of 

0.5 volt to terminal No. 2 of the right bank heated 
oxygen sensor (rear).

.

TECHNICAL DESCRIPTION

• The output signal of the right bank heated oxygen 

sensor (front) is compensated by the output sig-
nal of the right bank heated oxygen sensor (rear).

• The ENGINE-ECU checks for the right bank 

heated oxygen sensor (rear) output voltage.

.

DTC SET CONDITIONS

Check Conditions

• Battery voltage is between 10.7 and 16.1volts.

• Engine speed is above 20 r/min.

• Engine start achieved.

Judgment Criteria

• Signal check.

• 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: )

• Right bank heated oxygen sensor (rear) failed.

• Open circuit in right bank heated oxygen sensor 

(rear) output line.

• Open circuit in right bank heated oxygen sensor 

(rear) sensor ground.

• 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.

AK303063

THROTTLE BODY

RIGHT BANK

HEATED OXYGEN

SENSOR (REAR)

CONNECTOR: B-08

B-08 (GR)

AB

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-206

• MB991827: USB Cable

• MB991910: Main Harness A

• MB992044:  ENGINE-ECU Check Harness

STEP 1. Using diagnostic tool, check data list item AD: 
Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).

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 AD, 

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

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

output voltage should alternate between 0 and 0.6 to 1.0 
volts.

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

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 :  Then go to Step 2.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-207

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 all 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. 60 and ground.

• Warm engine. When the engine is revved, the output 

voltage should alternate between 0 and 0.6-1.0 volts.

(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 :  Then go to Step 3.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

03DB203A

B-20 HARNESS 

CONNECTOR