Mitsubishi 380. Manual - part 512

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-140

STEP 1. Using diagnostic tool , check data list item 6: 
Engine Coolant Temperature 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) Turn the ignition switch to the "ON" position.
(3) Set diagnostic tool  to the data reading mode for item 6, 

Engine Coolant Temperature Sensor.

• The actual engine coolant temperature and the temper-

ature shown with the diagnostic tool should approxi-
mately match.

(4) 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-104 at the engine 
coolant temperature 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 13.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

1

2

AK303037

HARNESS

CONNECTOR:

COMPONENT SIDE

CONNECTOR: B-104

AB

B-104 (B)

THROTTLE

BODY

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-141

STEP 3. Measure the sensor supply voltage at engine 
coolant temperature sensor harness side connector B-104.
(1) Disconnect the connector B-104 and measure at the 

harness side.

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

(3) Measure the voltage between terminal No. 1 and ground.

• Voltage should be between 4.5 and 4.9 volts.

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

Q: Is the measured voltage between 4.5 and 4.9 volts?

YES : Go to Step 7.
NO :  Go to Step 4.

1

2

AK303037

HARNESS

CONNECTOR:

COMPONENT SIDE

CONNECTOR: B-104

AB

B-104 (B)

THROTTLE

BODY

AK303039 AB

2 1

B-104 HARNESS 

CONNECTOR: 

COMPONENT SIDE

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-142

STEP 4. Measure the sensor supply 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) Disconnect the engine coolant temperature sensor 

connector B-104.

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

(4) Measure the voltage between terminal No. 56 and ground.

• Voltage should be between 4.5 and 4.9 volts.

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

Q: Is the measured voltage between 4.5 and 4.9 volts?

YES : Go to Step 5.
NO :  Go to Step 6.

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

YES : Repair harness wire between engine coolant 

temperature sensor connector B-104 (termial No. 1) 
and ENGINE-ECU connector B-20 (termial No. 56) 
because of open circuit. Then go to Step 13.

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

Connector Inspection 

P.00E-2

. Then go to Step 13.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

03DB228A

B-20 HARNESS 

CONNECTOR 

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-143

STEP 6. Check harness connector B-20 at ENGINE-ECU for 
damage.
Q: Is the harness connector in good condition?

YES : Go to Step 7.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 13.

STEP 7. Check the continuity at engine coolant 
temperature sensor harness side connector B-104.
(1) Disconnect the connector B-104 and measure at the 

harness side.

(2) Check for the continuity between terminal No. 2 and 

ground.

• Should be less than 2 ohms.

Q: Does continuity exist?

YES : Go to Step 10.
NO :  Go to Step 8.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

1

2

AK303037

HARNESS

CONNECTOR:

COMPONENT SIDE

CONNECTOR: B-104

AB

B-104 (B)

THROTTLE

BODY

AK303040

B-104 HARNESS

 CONNECTOR: 

COMPONENT SIDE

1

2

AB