Mitsubishi 380. Manual - part 581

MULTIPORT FUEL INJECTION (MPI) DIAG

MULTIPORT FUEL INJECTION (MPI)

13A-416

STEP 20. Check ENGINE-ECU connector B-21 for loose, 
corroded or damaged terminals, or terminals pushed back 
in the connector.
Q: Are the connector and terminals in good condition?

YES : Go to Step 21.
NO :  Repair or replace the damaged components. Refer to 

GROUP 00E, Harness Connector Inspection 

P.00E-2

.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

MULTIPORT FUEL INJECTION (MPI) DIAG

MULTIPORT FUEL INJECTION (MPI)

13A-417

STEP 21. Using the oscilloscope, check the vehicle speed 
sensor waveform at ENGINE-ECU connector B-21 by using 
check harness special tool MB992044.
(1) Disconnect all the connectors from the ENGINE-ECU.
(2) Connect special tool MB992044 (check harness) between 

the ENGINE-ECU and the body and control-side harness 
connector.

(3) Connect an oscilloscope probe to ENGINE-ECU connector 

B-21 terminal 85 and 82.

(4) Start the engine and drive the vehicle at constant speed of 

50 km/h.

(5) Check the vehicle speed sensor waveform.

• The vehicle speed sensor waveform should show a pat-

tern similar to the illustration. The maximum value 
should be 4.8 volts or more and the minimum value 0.8 
volt or less. The output waveform should not contain 
electrical noise.

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

Q: Is the waveform normal?

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 22.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

03DB239A

B-21 CONNECTOR: 

OSCILLO-
SCOPE

PROBE

ACX02131

NORMAL WAVEFORM

AD

(V)

5

0

MULTIPORT FUEL INJECTION (MPI) DIAG

MULTIPORT FUEL INJECTION (MPI)

13A-418

STEP 22. Replace the vehicle speed sensor.
(1) Replace the vehicle speed sensor. Refer to GROUP 22B, 

Manual transmission overhaul 

P.22B-30

.

(2) Test drive the vehicle.
(3) Check for Engine MPI diagnostic trouble code.

Q: Is the sensor operating properly?

YES : The procedure is complete.
NO :  Repeat the troubleshooting procedure again. Go back 

to Step 1.

MANUAL
TRANSMISSION

    

SPEED SENSOR

22DB018A

MULTIPORT FUEL INJECTION (MPI) DIAG

MULTIPORT FUEL INJECTION (MPI)

13A-419

DTC P0506: Idle Control Sytem RPM Lower Than Expected

.

TECHNICAL DESCRIPTION

• The amount of air taken in during idling is regu-

lated by the opening and closing of the throttle 
valve.

• The ENGINE-ECU checks the difference 

between the actual engine speed and the target 
engine speed.

.

Check Conditions

• Vehicle speed is 0 km/h.

• Intake air temperature is above -9.8°C.

• Engine speed is idle.

• Engine coolant temperature is above 60°C.

• Altitude is lower than 3000 meters.

Judgment Criteria

• Idle correction deviation is below -200r/min for 19 

seconds.

• MIL activated after 2 drive cycles.

• No Limp home.

.

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:)

• Throttle valve area is dirty.

• Throttle body assembly failed.

• Refer to component locations GROUP-

70

• Refer to configuration diagrams GROUP-

80

• Refer to circuit diagrams GROUP-

90

DIAGNOSIS

Required Special Tools

• : Diagnostic tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

STEP 1. Using diagnostic tool, read the diagnostic trouble 
code (DTC).

CAUTION

To prevent damage to diagnostic tool, always turn the igni-
tion switch to the "LOCK" (OFF) position before connect-
ing or disconnecting diagnostic tool.
(1) Connect diagnostic tool to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is a diagnostic trouble code other than P0506 set?

YES : Refer to Diagnostic Trouble Code Chart 

P.13A-17

.

NO :  Go to Step 2.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827