Mitsubishi 380. Manual - part 482

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-20

NOTE: 

• Check that the ENGINE-ECU ground circuit is normal before checking for the cause of the problem.
• After the ENGINE-ECU detects a malfunction, a diagnostic trouble code is recorded the next time the 

engine is started and the same malfunction is re-detected. However, for items marked with a "*", the diag-
nostic trouble code is recorded on the first detection of the malfunction.

• After the Check Engine Warning Lamp) illuminates, it will be switched off under the following conditions.

• When the ENGINE-ECU monitored the engine malfunction four times* and met set condition require-

ments, it detected no malfunction. 

*: In this case, "one time" indicates from engine start to stop.

• For misfiring or a fuel trim malfunction, when driving conditions (engine speed, engine coolant temper-

ature, etc.) are similar to those when the malfunction was first recorded.

• Sensor 1 indicates the sensor mounted at a position closest to the engine, and sensor 2 indicates the sen-

sor mounted at the position second closest to the engine.

• Bank 1 indicates the right bank side cylinder, and Bank 2 indicates the left bank side cylinder.

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-21

SYMPTOM CHART

M1131151500726

CAUTION

During diagnosis, a DTC associated with other system may be set when the ignition switch is turned 
on with connector(s) disconnected. On completion, confirm all systems for DTC(s). If DTC(s) are set, 
erase them all.

CAUTION

Disconnecting the battery cables or removing the combination meter will erase the learned value of 
the fuel gauge. To recover the learned value, input a vehicle speed (by actually driving the vehicle or 
inputting a simulated vehicle speed), and stop the vehicle. This will complete the learning process.

.

NOTE: Check that the ENGINE-ECU ground circuit is normal before checking for the cause of the problem.

TROUBLE SYMPTOMS

INSPECTION 
PROCEDURE

REFERENCE 
PAGE

Communication 
with diagnostic 
tool is 
impossible

Communication with all systems is not possible

1

P.13A-539

Communication with ENGINE-ECU only is not 
possible

2

P.13A-541

Check Engine 
Warning Lamp) 
and related 
parts

The Check Engine Lamp) does not illuminate right 
after the ignition switch is turned to the "ON" position

3

P.13A-543

The Check Engine Warning Lamp) remains illuminated 
and never goes out

4

P.13A-544

Starting

Cranks, won't start

5

P.13A-546

Starts up and dies

6

P.13A-553

Hard starting

7

P.13A-560

Idling stability 
(improper 
idling)

Unstable idle (rough idle, hunting)

8

P.13A-566

Idle speed is high (improper idle speed)

9

P.13A-571

Idle speed is low (improper idle speed)

10

P.13A-573

Idling stability 
(engine stalls)

When the engine is cold, it stalls at idle (die out)

11

P.13A-574

When the engine is hot, it stalls at idle (die out)

12

P.13A-577

The engine stalls when accelerating (pass out)

13

P.13A-581

The engine stalls when decelerating

14

P.13A-583

Driving

Hesitation, sag or stumble

15

P.13A-585

Acceleration shock

16

P.13A-588

Deceleration shock

17

P.13A-589

Poor acceleration

18

P.13A-590

Surge

19

P.13A-594

Knocking

20

P.13A-598

Dieseling (Run-on)

21

P.13A-599

Too high CO and HC concentration when idling

22

P.13A-600

IM240 test 
failure

Purge flow test of the evaporative emission canister 
failure

23

P.13A-602

Power supply system and ignition switch-IG system

24

P.13A-604

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-22

.

PROBLEM SYMPTOMS TABLE (FOR YOUR INFORMATION)

Fuel pump system

25

P.13A-613

Ignition switch-ST system and transmission range switch system

26

P.13A-624

Ignition circuit system

27

P.13A-628

A/C system

28

P.13A-634

TROUBLE SYMPTOMS

INSPECTION 
PROCEDURE

REFERENCE 
PAGE

ITEMS

SYMPTOM

At starting

Won't start 

The starter cranks the engine, but there is no combustion within the 
cylinders, and the engine won't start.

Starts up and 
dies

The engine starts, but then engine soon stalls.

Hard starting

Engine starts after cranking a while.

Idling stability

Hunting

Engine speed doesn't remain constant; changes at idle.

Rough idle

Usually, a judgement can be based upon the movement of the 
tachometer pointer, and the vibration transmitted to the steering wheel, 
shift lever, body, etc.

Incorrect idle 
speed

The engine doesn't idle at the correct speed.

Engine stall (die 
out)

The engine stalls when the foot is taken from the accelerator pedal, 
regardless of whether the vehicle is moving or not. 

Engine stall 
(pass out)

The engine stalls when the accelerator pedal is depressed.

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-23

At driving

Hesitation Sag

"Hesitation" is the delay in 
response of the vehicle speed 
(engine speed). This occurs when 
the accelerator is depressed in 
order to accelerate from the speed 
at which the vehicle is now 
traveling, or a temporary drop in 
vehicle speed (engine speed) 
during such acceleration. 
Serious hesitation is called "sag".

Poor 
acceleration

Poor acceleration is inability to obtain an acceleration corresponding to 
the degree of throttle opening, even though acceleration is smooth. 
Also the inability to reach maximum speed. 

Stumble

Engine speed increase is delayed 
when the accelerator pedal is 
initially depressed for acceleration. 

Shock

The feeling of a comparatively large impact or vibration when the 
engine is accelerated or decelerated. 

Surge

This is slight acceleration and deceleration feel usually felt during 
steady, light throttle cruise. Most notable under light loads.

Knocking

A sharp sound during driving, which sounds like a hammer striking the 
cylinder walls. It makes poor driveability.

At stopped

Run on 
("Dieseling") 

The condition in which the engine continues to run after the ignition 
switch is turned to the "LOCK" (OFF) position. Also called "dieseling".

ITEMS

SYMPTOM

AKX01361

VEHICLE

SPEED

TIME

NORMAL

HESITATION

SAG

INITIAL

ACCELE-

RATOR

PEDAL

DEPRE-

SSION

AKX01361AB

AKX01362

VEHICLE

SPEED

TIME

NORMAL

STUMBLE

INITIAL

ACCEL-

ERATOR

PEDAL 

DEP-

RESSION

IDLING