Mitsubishi 380. Manual - part 509

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-128

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 the engine coolant temperature sensor(On 
Car).
(1) Ensure engine coolant temperature is between 20

° C and 

below 100

° C.

(2) Disconnect the engine coolant temperature sensor 

connector B-104.

(3) Check the resistance between terminal No. 1 & No. 2 of the 

sensor.

Q: Is the measured resistance between 186

Ω and 2.4 kΩ?

YES : Go to Step 3.
NO :  Replace the sensor and go to Step 10.

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-129

STEP 3. Check the engine coolant temperature sensor(Off 
Car).
(1) Disconnect the engine coolant temperature sensor 

connector B-104.

(2) Remove the engine coolant temperature sensor.

WARNING

Ensure cooling system pressure is released at radia-
tor cap slowly, prior to removing sensor to avoid get-
ting burned by hot coolant.

(3) With the temperature sensing portion of engine coolant 

temperature sensor immersed in hot water, measure 
resistance.Refer to Service Specifications 

13A-677

(4) Apply 3M

™ AAD part number 8731 or equivalent on the 

screw section of the engine coolant temperature sensor.

(5) Install the engine coolant temperature sensor, and tighten 

to the specified torque.

Tightening torque: 21 

± 3 N⋅m 

Q: Is the measured resistance normal?

YES : Go to Step 4.
NO :  Go to Step 6.

STEP 4. Check harness connector B-104 at the engine 
coolant temperature sensor for damage.
Q: Is the connector in good condition?

YES : Go to Step 5.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 11.

1

2

AK303037

HARNESS

CONNECTOR:

COMPONENT SIDE

CONNECTOR: B-104

AB

B-104 (B)

THROTTLE

BODY

AKX01622

AKX01623 AB

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-130

STEP 5. Check for 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 8.
NO :  Go to Step 6.

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 it. Then go to Step 11.

1

2

AK303037

HARNESS

CONNECTOR:

COMPONENT SIDE

CONNECTOR: B-104

AB

B-104 (B)

THROTTLE

BODY

AK000235

B-104 HARNESS

CONNECTOR: 

COMPONENT SIDE

1

2

AQ

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-131

STEP 7. Check for harness damage between engine 
coolant temperature sensor connector B-104 (terminal No. 
2) and ENGINE-ECU connector B-20 (terminal No. 12).
Q: Is the harness wire in good condition?

YES : Go to Step 8.
NO :  Repair it. Then go to Step 11.

STEP 8. Check harness connector B-20 at ENGINE-ECU for 
damage.
Q: Is the harness connector in good condition?

YES : Go to Step 9.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 11.

1

2

AK303037

HARNESS

CONNECTOR:

COMPONENT SIDE

CONNECTOR: B-104

AB

B-104 (B)

THROTTLE

BODY

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER