Mitsubishi Space Star. Manual - part 59

MPI  – 

Troubleshooting

13B-23

NG

Replace the engine-ECU.

OK

Transient malfunction
(Refer to GROUP 00 – Points to
Note for Intermittent Malfunctions.)

OK

Check the trouble symptoms.

OK

Check the following connector:
B-31

Repair

NG

OK

Check the harness wire between
the oxygen sensor (rear) and the
engine-ECU, and repair if necessary.

NG

Check the following connector:
B-31

NG

Repair

OK

Measure at engine-ECU connector
B-31.



Measure the voltage at the
engine-ECU terminal.



Engine: 2,500 r/min (after
warming up)



Voltage between terminal 75 and
earth
OK: 0 V and 0.8 V alternate.

OK

Check the harness wire between
the oxygen sensor (rear) and the
engine-ECU, and repair if necessary.

OK

NG

Repair

Check the following connector:
B-31

OK

Check the harness wire between
the oxygen sensor (rear) and the
engine-ECU, and repair if necessary.

NG

Replace the engine-ECU.

OK

Check the trouble symptoms.

OK

Check the harness wire between
the oxygen sensor (rear) and the
engine-ECU.

NG

Repair

Repair

OK

Measure at oxygen sensor (rear)
connector B-90.



Disconnect the connector and
measure at the harness side.



Resistance between terminal 2
and earth
OK: 2 

Ω

 or less

NG

Check the following connector:
B-31

NG

Check the following connector:
B-90

NG

Repair

(2) NG

Check the oxygen sensor (rear). 
(Refer to P.13B-80.)

NG

Replace

Repair

OK

Measure at oxygen sensor (rear)
connector B-90.



Measure the voltage at the
oxygen sensor (rear) terminal



Engine: 2,500 r/min (after
warming up)

(1) Voltage between terminal 2 and

earth
OK: 0.5 V or less

(2) Voltage between terminal 1 and

earth
OK: 0 V and 0.8 V alternate.

(1) NG

Check the following connector:
B-31

NG

MPI  – 

Troubleshooting

13B-24

Code No. P0141 Oxygen sensor heater (rear) system
<sensor 2>

Probable cause

Range of Check



The engine coolant temperature is approx. 20



C or more.



The oxygen sensor heater (rear) remains on.



The engine speed is 50 r/min or more.



Battery voltage is 11 – 16 V.

Set Conditions



The current, which flows through the oxygen sensor heater (rear), is 0.2 A
or less or 3.5 A or more for six seconds.



Malfunction of oxygen sensor heater (rear)



Open or short circuit in the oxygen sensor heater
(rear) circuit or loose connector contact



Malfunction of engine-ECU

NG

Replace the engine-ECU.

OK

Check the trouble symptoms.

OK

Transient malfunction
(Refer to GROUP 00 – Points to
Note for Intermittent Malfunctions.)

OK

Check the harness wires between
the oxygen sensor (rear) and the
engine-ECU, and between the
oxygen sensor (rear) and the engine
control relay.

NG

Repair

OK

Check the following connector:
B-30

NG

Repair

OK

Check the harness wire between
the oxygen sensor (rear) and the
engine-ECU, and repair if necessary.

Repair

NG

Check the following connector:
B-30

NG

OK

Measure at engine-ECU connector
B-30.



Measure the voltage at the
engine-ECU terminal.



Ignition switch: ON



Voltage between terminal 54 and
earth
OK: System voltage

OK

Check the harness wires between
the oxygen sensor (rear) and the
engine control relay, and repair if
necessary.

Repair

NG

Check the following connector:
B-26

NG

OK

Measure at oxygen sensor (rear)
connector B-90.



Disconnect the connector and
measure at the harness side.



Ignition switch: ON



Voltage between terminal 3 and
earth
OK: System voltage

OK

Check the following connector:
B-90

NG

Repair

Measure at oxygen sensor (rear)
connector B-90.



Disconnect the connector and
measure at the harness side.



Resistance between terminals 3
and 4
OK: 11  – 18 

Ω

NG

Replace

MPI  – 

Troubleshooting

13B-25

Code No. P0170 Abnormal fuel system

Probable cause

Range of Check



Engine: Being learning the air-fuel ratio

Set Conditions



Two seconds or more have been passed while the fuel injection amount
compensation value is too low.

or



Two seconds or more have been passed while the fuel injection amount
compensation value is too high.



Incorrect fuel pressure



Malfunction of injector



Malfunction of oxygen sensor (front)



Malfunction of intake air temperature sensor



Malfunction of vacuum sensor



Malfunction of engine-ECU

Replace the engine-ECU.

OK

Replace the engine-ECU.

OK

Less than zero



Check for fuel leaks from injector.



Check for entry of foreign matter (water, kerosene, etc.) into
the fuel.



Check for clogging of the injector.



Check for clogging of the fuel filter and fuel line.



Check the fuel pump (insufficient discharge rate).



Check for exhaust leaks (oxygen sensor installation section,
cracks in exhaust manifold, cracks in front pipe, etc.).



Check for entry of foreign matter (water, kerosene, etc.) into
the fuel.

OK

NG

Repair

NG

NG

OK

MUT-

II

 Data list

81 Long-term fuel compensation (Refer to P.13B-65.)



Is fuel trim more or less than zero?

More than zero

Check if air was drawn
into the intake system.

OK

Check the fuel pressure (Refer to P.13B-67*.)

NG

Repair

NG

NG

OK

Check the harness wire between the engine-ECU and the
injector connector.

NG

Repair

NG

NG

OK

Check the following connectors: A-48, A-49, A-54, A-60

NG

NG

Replace

NG

MUT-

II

 Data list

13 Intake air temperature sensor (Refer to P.13B-65.)

NG

Check the intake air temperature sensor system 
(Refer to P.13B-12, INSPECTION PROCEDURE FOR DIAGNOS-
TIC TROUBLE CODE P0110.)

OK

Check the injector (Refer to P.13B-74*.)

MUT-

II

 Data list

21 Engine coolant temperature sensor (Refer to P.13B-65.)

NG

Check the engine coolant temperature sensor system 
(Refer to P.13B-13, INSPECTION PROCEDURE FOR DIAGNOS-
TIC TROUBLE CODE P0115.)

OK

MUT-

II

 Data list

32 Vacuum sensor (Refer to P.13B-65.)

NG

Check the vacuum sensor system 
(Refer to P.13B-10, INSPECTION PROCEDURE FOR DIAGNOS-
TIC TROUBLE CODE P0105.)

OK

NOTE:
*:

Refer to the ’99 SPACE STAR Workshop Manual (Pub. No. CMXE99E1)

MPI  – 

Troubleshooting

13B-26

Code No. P0201 No. 1 injector system

Code No. P0202 No. 2 injector system

Code No. P0203 No. 3 injector system

Code No. P0204 No. 4 injector system

Probable cause

Range of Check



Engine speed is approx. 50 – 1,000 r/min



The throttle position sensor output voltage is 1.15 V or less.



Actuator test by MUT-

II

 is not carried out.

Set Conditions



Surge voltage of injector coil is not detected for 2 seconds.



Malfunction of the injector



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



Malfunction of the engine-ECU

Replace the engine-ECU.

NG

OK

Intermittent malfunction
(Refer to GROUP 00 – Points to Note for Intermittent Malfunctions.)

NG

Use an analyzer to measure the signal wave form at injector
connectors A-48, A-49, A-54, A-60.



Connect the connector using test harness (MB991348), and
measure at pick-up harness.



Engine: Idling



The voltage between terminal 2 and earth
OK: A normal waveform should be displayed as described

on P.13B-59* (INSPECTION PROCEDURE USING AN
ANALYZER).

OK

Check trouble symptoms.

NG

Measure at the engine-ECU connector B-28.



Disconnect the connector, and measure at the harness side.



Voltage between 1, 2, 14, 15 and earth (Ignition switch: ON)
OK: System voltage

Check the harness wire between the engine-ECU and the injector
connector, and repair if necessary.

OK

NG

Repair

NG

NG

OK

Check the following connector: B-28

Replace

NG

MUT-

II

 Actuator Test

01 No. 1 injector
02 No. 2 injector
03 No. 3 injector
04 No. 4 injector

OK: The idling condition should change

OK

Intermittent malfunction
(Refer to GROUP 00 – Points to Note for Intermittent Malfunctions.)

NG

Measure at the injector connectors A-48, A-49, A-54, A-60.



Disconnect the connector, and measure at the harness side.



Voltage between 1 and earth (Ignition switch: ON)
OK: System voltage

Check the following connectors:
A-48, A-49, A-54, A-60

NG

OK

Check the injector. (Refer to P.13B-74*.)

NG

Check the harness wire between the engine control relay and
the injector connector, and repair if necessary.

OK

Repair

NOTE:
*:

Refer to the ’99 SPACE STAR Workshop Manual (Pub. No. CMXE99E1)