Mitsubishi 380. Manual - part 577

MULTIPORT FUEL INJECTION (MPI) DIAG

MULTIPORT FUEL INJECTION (MPI)

13A-400

.

CIRCUIT OPERATION

• The vehicle speed sensor (manual) generates a 

0 

⇔ 5 volt pulse signal when the driven (pinion) 

gear rotates. The pulse signal frequency 
increases with a rise in driven gear speed.

• The vehicle speed sensor (manual) is connected 

to the ENGINE-ECU connector B-21 (terminals 
82 and 85) via the vehicle speed sensor connec-
tor B-121 (terminals 1 and 2).

• The ENGINE-ECU detects the vehicle speed by 

the signal input to terminal 85.

• The vehicle speed sensor generates the pulse 

signal as the teeth of the driven gear engages 
with the vehicle speed sensor gear.

.

DTC SET CONDITIONS

Check Conditions

• M/T gear range position: 1, 2, 3, 4, 5 and reverse

• Engine speed: 1,000 r/min or more.

Judgement Criteria

• (P0500) will be set, and the check engine warn-

ing lamp will come on after 2 drive cycles.

.

DRIVE CYCLE PATTERN

Start and drive vehicle at 50km/h for 3mins. Stop 
vehicle, turn engine "OFF". Restart engine and drive 
vehicle again at 50km/h for 3 mins. and confirm if 
speedometer is working and the status of the engine 
warning lamp.

.

TROUBLESHOOTING HINTS (THE MOST 
LIKELY CAUSES FOR THIS CODE TO BE 
SET ARE:)

• Malfunction of the vehicle speed sensor (M/T)

• Damaged harness or connector

Circuit drawings

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

• Refer to component locations GROUP-

70

DIAGNOSIS

Required Special Tool:

• MB991958: Diagnostic Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

• MB992044: Engine-ECU Check Harness

1

2

3

4

AK303017

CONNECTOR: B-17X

FRONT OF VEHICLE

B-17X

AB

HARNESS

CONNECTOR:

COMPONENT SIDE

RELAY BOX

MULTIPORT FUEL INJECTION (MPI) DIAG

MULTIPORT FUEL INJECTION (MPI)

13A-401

STEP 1. Using diagnostic tool MB991958, check MPI data 
list item 4: Vehicle Speed Sensor System.

CAUTION

To prevent damage to diagnostic tool MB991958, always 
turn the ignition switch to the "LOCK" (OFF) position 
before connecting or disconnecting diagnostic tool 
MB991958.
(1) Connect diagnostic tool MB991958 to the data link 

connector.

(2) Start the engine.
(3) Set diagnostic tool MB991958 to the data reading mode.

• Item 4: Vehicle Speed Sensor.

• When driving at a constant speed of 50km/h, the dis-

play should be "1,900 

− 2,100 r/min".

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

Q: Is the sensor within the specified range?

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 Malfunction 

P.00-14

.

NO :  Go to Step 2.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MPI) DIAG

MULTIPORT FUEL INJECTION (MPI)

13A-402

STEP 2. Measure the power supply voltage at the vehicle 
speed sensor connector B-121.
(1) Disconnect connector B-121 and measure at the harness 

side.

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

(3) Measure the voltage between terminal 1 and ground.

• The voltage should measure battery positive voltage.

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

Q: Is the measured voltage battery positive voltage?

YES : Go to Step 5.
NO :  Go to Step 3.

CONNECTOR:  B-121

    

VEHICLE

SPEED SENSOR
        B-121

03DB234A

03DB233A

B-121 HARNESS

CONNECTOR:

MULTIPORT FUEL INJECTION (MPI) DIAG

MULTIPORT FUEL INJECTION (MPI)

13A-403

STEP 3. Check harness connector B-17X at the MPI relay 
for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 4.
NO :  Repair or replace the damaged components. Refer to 

GROUP 00E, Harness Connector Inspection 

P.00E-2

.

STEP 4. Check for harness damage between MPI relay 
connector B-17X (terminal No. 4) and vehicle speed sensor 
connector B-121 (terminal No. 1).
Q: Is the harness wire in good condition?

YES : Go to Step 5.
NO :  Repair harness wire between MPI relay connector 

B-17X (terminal No. 4) and vehicle speed sensor 
connector B-121 (terminal No. 1).

1

2

3

4

AK303017

CONNECTOR: B-17X

FRONT OF VEHICLE

B-17X

AB

HARNESS

CONNECTOR:

COMPONENT SIDE

RELAY BOX

1

2

3

4

AK303017

CONNECTOR: B-17X

FRONT OF VEHICLE

B-17X

AB

HARNESS

CONNECTOR:

COMPONENT SIDE

RELAY BOX