Mitsubishi 380. Manual - part 497

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-80

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 P0101 set?

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

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-81

DTC P0102: Mass Airflow Circuit Low Input.

CAUTION

If DTC P0102 has been set, TCL related DTC 
U1120 is also set. After P0102 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 below lower threshold 

(0-283.0 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.

• Open or 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

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-82

DIAGNOSIS

Required Special Tools:

• : Diagnostic Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

• MB992044:  ECU Check Harness

STEP 1. 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 :  Go to Step 2.

STEP 2. Check harness connector B-10 at mass airflow 
sensor for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 3.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 11.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

CONNECTOR: B-10

B-10 (GR)

03DB218A

HARNESS

CONNECTOR:

COMPONENT SIDE

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-83

STEP 3. Measure the power supply voltage at mass airflow 
sensor harness side connector B-10.
(1) Disconnect the connector B-10 and measure at the harness 

side.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal No. 2 and ground.

• Voltage should be battery positive voltage.

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

Q: Is battery positive voltage (approximately 12 volts) 

present?
YES : Go to Step 5.
NO :  Go to Step 4.

STEP 4. Check harness connector B-17X at MPI relay for 
damage.
Q: Is the harness connector in good condition?

YES : Repair harness wire between MPI relay connector 

B-17X (terminal No. 4) and mass airflow sensor 
connector B-10 (terminal No. 2) because of open 
circuit or short circuit to ground. Then go to Step 11.

NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 11.

CONNECTOR: B-10

B-10 (GR)

03DB218A

HARNESS

CONNECTOR:

COMPONENT SIDE

03DB220A

B-10 HARNESS 

CONNECTOR: 

COMPONENT SIDE

1

2

3

4

AK303017

CONNECTOR: B-17X

FRONT OF VEHICLE

B-17X

AB

HARNESS

CONNECTOR:

COMPONENT SIDE

RELAY BOX