Mitsubishi 380. Manual - part 498

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-84

STEP 5. Check harness connector B-20 at ENGINE-ECU for 
damage.
Q: Is the harness connector in good condition?

YES : Go to Step 6.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 11.

STEP 6. Measure the sensor output voltage at 
ENGINE-ECU connector B-20 by using  ECU check 
harness special tool MB992044.
(1) Disconnect the all ENGINE-ECU connectors and connect  

ECU check harness special tool MB992044 between the 
separated connectors.

(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 43 and ground.

• When the engine is revved, voltage should be increase 

in response to revving.

Q: Is the measured voltage normal?

YES : Go to Step 9.
NO :  Go to Step 7.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

03DB225A

B-20 HARNESS 

CONNECTOR 

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-85

STEP 7. Check for open circuit or short circuit to ground 
between mass airflow sensor connector B-10 (terminal No. 
5) and ENGINE-ECU connector B-20 (terminal No. 43).
Q: Is the harness wire in good condition?

YES : Replace the mass airflow sensor. Then go to Step 8.
NO :  Repair it. Then go to Step 11.

STEP 8. Replace the mass airflow sensor.
(1) Replace the mass airflow sensor.
(2) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− EOBD Drive Cycle − 

P.13A-11

.

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

Q: Is DTC P0102 set?

YES : Then go to Step 11.
NO :  The inspection is complete.

CONNECTOR: B-10

B-10 (GR)

03DB218A

HARNESS

CONNECTOR:

COMPONENT SIDE

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

CONNECTOR: B-10

B-10 (GR)

03DB218A

HARNESS

CONNECTOR:

COMPONENT SIDE

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-86

STEP 9. Check harness connector B-20 at ENGINE-ECU for 
damage.
Q: Is the harness connector in good condition?

YES : Go to Step 10.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 10.

STEP 10. Using diagnostic tool , check data list item AA: 
Mass Airflow Sensor.

CAUTION

To prevent damage to diagnostic tool , always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting diagnostic tool .
(1) Connect diagnostic tool  to the data link connector.
(2) Start the engine and run at idle.
(3) Set diagnostic tool  to the data reading mode for item AA, 

Mass Airflow Sensor.

(4) Warm up the engine to normal operating temperature: 80

°C 

to 95

°C (176°F to 203°F).

• The standard value during idling should be approxi-

mately 4.7 g/sec.

• When the engine is revved, the mass airflow rate should 

increase according to the increase in engine speed.

(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 11.

STEP 11. 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 P0102 set?

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

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-87

DTC P0103: Mass Airflow Circuit High Input.

CAUTION

If DTC P0103 has been set, TCL related DTC 
U1120 is also set. After P0103 has been diag-
nosed, don't forget to erase DTC U1120.

.

CIRCUIT OPERATION

• The mass airflow sensor power is supplied from 

the MPI relay (terminal No. 4), and the ground is 
provided on the ENGINE-ECU (terminal No. 11).

• 5-volt power is applied to the mass airflow sensor 

output terminal (terminal No. 4) from the 
ENGINE-ECU (terminal No. 11).

.

TECHNICAL DESCRIPTION

• While the engine is running, the mass airflow 

sensor outputs voltage which corresponds to the 
mass airflow rate.

• The ENGINE-ECU checks whether the voltage 

output by the mass airflow sensor while the 
engine is running is within a specified speed and 
load range.

.

DTC SET CONDITIONS

Check Conditions

• Battery voltage is above 8.01 volts.

Crankshaft revolution is above 150 r/min.

Judgement Criteria

• Air flow sensor output is above upper threshold 

(40.9-903.0 kg/h) for 4 seconds.

• MIL is activated immediately.

• No limp home mode.

.

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:)

• Mass airflow sensor failed.

• Shorted mass airflow sensor, circuit, or connector 

damage.

• Refer to component locations GROUP-

70

• Refer to configuration diagrams GROUP-

80

• Refer to circuit diagrams GROUP-

90

1

2

3

4

1

2

3

4

1

2

3

4

1

2

3

4

AK303014

CONNECTOR: B-17X

MFI RELAY

MFI RELAY

FRONT OF VEHICLE

B-17X

AB

CONNECTOR: B-10

B-10 (GR)

MASS

AIRFLOW

SENSOR

03DB217A

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER