Mitsubishi Space Star. Manual - part 69

MPI  – 

Troubleshooting

13B-63

INSPECTION PROCEDURE 31

Ignition circuit system

Probable cause

The engine-ECU interrupts the ignition coil primary current by turning the power
transistor inside the engine-ECU ON and OFF.



Malfunction of ignition coil



Malfunction of ignition failure sensor



Improper connector contact, open circuit or
short-circuited harness wire



Malfunction of the engine-ECU

NG

To the next page

OK

Replace the engine-ECU.

NG

Repair

NG

Check the harness wire between the
engine-ECU and ignition coil connector.

OK

Check trouble symptom.

NG

Repair

OK

Check the following connector:
A-89, A-91

OK

Check trouble symptom.

NG

Repair

Check the following connector:
B-28

(2) NG

NG

OK

Check trouble symptom.

Check the harness wire between the
ignition coil and ignition failure sensor
connector, and repair if necessary.

NG

Repair

Check the following connector:
A-96

Measure at the ignition coil connectors
A-89, A-91.



Disconnect the connector, and
measure at the harness side.

(1) Voltage between 1 and earth

(Ignition switch: ON)
OK: Battery positive voltage

(2) Voltage between 3 and earth

(Engine: Cranking)
OK: 0.5  – 4.0 V

(3) Continuity between 2 and earth

OK: Continuity

(1) NG

OK

OK

Check the ignition switch. (Refer to GROUP 54 – Ignition Switch.)

Check the harness wire
between the ignition
failure sensor and ignition
switch connector.

NG

Repair

NG

OK

Check trouble symptom.

OK

Measure at the ignition failure sensor connector A-96.



Disconnect the connector and measure at the harness side.
Voltage between 4 and ground (Ignition switch: ON)
OK: System voltage

NG

Check the following
connector:  B-18, B-58

NG

Repair

Check the ignition failure sensor. 
(Refer to GROUP 16 – Ignition System.)

NG

Replace

OK

Check the ignition coil. 
(Refer to GROUP 16 – Ignition System.)

NG

Replace

Check the harness wire between the
ignition coil connector and ground, and
repair if necessary.

(3) NG

MPI  – 

Troubleshooting

13B-64

OK

Replace the engine-ECU.

OK

Replace the ignition failure sensor.

Check the harness wire
between the engine-ECU
and the ignition failure
sensor connector.

NG

Repair

NG

OK

Check trouble symptom.

NG

Check the following
connector: A-96

NG

Repair

OK

Measure at the engine-ECU connector B-30.



Measure with the connector connected.



Voltage between 58 and earth
(Engine: Cranking or 3,000 r/min)
OK: 0.3  – 3.0 V

2. NG

Check the harness wire between the ignition failure sensor and
earth, and repair if necessary.

OK

Measure at the ignition failure sensor connector A-96.



Disconnect the connector and measure at the harness side.

1. Voltage between 2 and earth (Ignition switch: ON)

OK: 4 V or more

2. Continuity between 1 and earth

OK: Continuity

1. NG

There is an open or short-circuit the ignition signal output harness
of the ignition failure sensor, so check and repair the harness.

From the previous page

NG

Repair

OK

Check trouble symptom.

NG

Check the following
connector: B-30

MPI  – 

Troubleshooting

13B-65

DATA LIST REFERENCE TABLE

NOTE
*1: In a new vehicle [driven approximately 500 km or less], the air intake plenum pressure is sometimes

10 % higher than the standard pressure.

*2: The injector drive time represents the time when the cranking speed is at 250 r/min or below when

the power supply voltage is 11 V.

*3: In a new vehicle [driven approximately 500 km or less], the injector drive time is sometimes 10 %

longer than the standard time.

*4: In a new vehicle [driven approximately 500 km or less], the step of the stepper motor is sometimes

30 steps greater than the standard value.

Item
No.

Inspection
item

Inspection contents

Normal condition

Inspection
procedure
No.

Reference
page

11

Oxygen
sensor
(front)

Engine: After having 

 warmed up

Air/fuel mixture is 
made leaner when

When at 4,000 r/min,
engine is suddenly 
decelerated

200 mV or less

Code No.
P0130

13B-19

made leaner when
decelerating, and is
made richer when
racing.

When engine is 
suddenly raced

600 – 1,000 mV

Engine: After having 

 warmed up

The oxygen sensor 
signal is used to
check the air/fuel

Engine is idling

400 mV or less
(Changes)
600 – 1,000 mV

check the air/fuel
mixture 
ratio, and control 
condition is also 
checked by the ECU.

2,500 r/min

13

Intake air 
temperature
sensor

Ignition switch: ON or
with engine running

When intake air 
temperature is
–20



C

–20



C

Code No.
P0110

13B-12

When intake air 
temperature is 0



C

0



C

When intake air 
temperature is 20



C

20



C

When intake air 
temperature is 40



C

40



C

When intake air 
temperature is 80



C

80



C

14

Throttle
position

Ignition switch: ON

Set to idle position

300 – 1,000 mV

Code No.
P0120

13B-16

position
sensor

Gradually open

Increases in 
proportion to 
throttle opening 
angle

P0120

Open fully

4,500 – 5,500 mV

MPI  – 

Troubleshooting

13B-66

Item
No.

Inspection
item

Inspection contents

Normal condition

Inspection
procedure
No.

Reference
page

16

Power 
supply 
voltage

Ignition switch: ON

System voltage

Procedure
No. 25

13B-59

18

Cranking
signal 

Ignition switch: ON

Engine: Stopped

OFF

Procedure
No. 27

13B-61

signal 
(ignition
switch-ST)

Engine: Cranking

ON

No. 27

21

Engine 
coolant 
temperature
sensor

Ignition switch: ON or
with engine running

When engine 
coolant temperature
is –20



C

–20



C

Code No.
P0115

13B-13

sensor

When engine 
coolant temperature
is 0



C

0



C

When engine 
coolant temperature
is 20



C

20



C

When engine 
coolant temperature
is 40



C

40



C

When engine 
coolant temperature
is 80



C

80



C

22

Crank
angle sen-
sor



Engine: Cranking



Tachometer: 
Connected

Compare the engine
speed readings on
the tachometer and
the MUT-

II

.

Accord

Code No.

P0335

13B-25



Engine: Idling



Idle position 
switch: ON

When engine 
coolant temperature
is –20



C

1,475 – 1,675
r/min

When engine 
coolant temperature
is 0



C

1,345 – 1,545
r/min

When engine 
coolant temperature
is 20



C

1,200 – 1,400
r/min

When engine 
coolant temperature
is 40



C

1,160 – 1,225
r/min

When engine 
coolant temperature
is 80



C

650 – 850 r/min

24

Vehicle
speed sen-
sor

Drive at 40 km/h

Approximately 40
km/h

Code No.
P0500

13B-35