Mitsubishi Colt Ralliart. Manual - part 98

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-346

NOTE: *:The average voltage is shown when an 
analog voltmeter is used (because the average volt-
age might not be shown stably when digital voltmeter 
is used).

81

A/C relay 

• Engine: Idle speed

• A/C switch: OFF → ON (A/C compressor is 

operating)

System voltage 

→ 1 V or 

less

82

Backup power 
supply

Ignition switch: "LOCK" (OFF)

System voltage

83

Accelerator pedal 
position sensor 
(main)

Ignition switch: ON

Release the 
accelerator pedal

0.8 

− 1.2 V

Depress the 
accelerator pedal fully

4.0 V or more

85

Power supply 
voltage applied to 
accelerator pedal 
position sensor 
(main)

Ignition switch: ON

4.9 

− 5.1 V

86

Power supply 
voltage applied to 
accelerator pedal 
position sensor (sub)

Ignition switch: ON

4.9 

− 5.1 V

88

Accelerator pedal 
position sensor (sub)

Ignition switch: ON

Release the 
accelerator pedal

0.3 

− 0.7 V

Depress the 
accelerator pedal fully

2 V or more

95

Fan control relay

Fan inactive state

System voltage

Fan low-speed rotation state

1 V or less

97

Oxygen sensor 
(rear)

Engine: Running at 2,500 r/min after warmed 
up

0.2 

− 0.8 V (After several 

seconds have elapsed)

107

Engine control relay Ignition switch: "LOCK" (OFF)

System voltage

Ignition switch: ON

1 V or less

110

Fuel pump relay 

Ignition switch: ON

System voltage

Engine: Idle speed

1 V or less

122

Ignition switch 

− IG

Ignition switch: ON

System voltage

123

Throttle valve control 
servo relay

Ignition switch: "LOCK" (OFF)

0 

− 0.1 V

Ignition switch: ON

1 V or less

128

Stop lamp switch

Release the brake pedal

1 V or less

Depress the brake pedal

System voltage

Terminal 
No.

Check item

Check condition (Engine condition)

Normal condition

Main

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TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-347

CHECK CHART FOR RESISTANCE AND 
CONTINUITY BETWEEN TERMINALS

1. Turn the ignition switch to "LOCK" (OFF) position.
2. Disconnect the engine-ECU connector or 

engine-CVT-ECU connector.

3. Measure the resistance and check for continuity 

between the terminals of the engine-ECU <M/T> 
or engine-CVT-ECU <CVT> harness-side 
connector while referring to the check chart.
NOTE: 

.

1. When measuring resistance and checking 

continuity, a harness for checking contact pin 
pressure should be used instead of inserting a 
test probe.

2. Checking need not be carried out in the order 

given in the chart.

CAUTION

If the terminals that should be checked are mis-
taken, or if connector terminals are not correctly 
shorted to earth, damage may be caused to the 
vehicle wiring, sensors, engine-ECU <M/T> or 
engine-CVT-ECU <CVT> and/or ohmmeter. Be 
careful to prevent this!
4. If the ohmmeter shows any deviation from the 

standard value, check the corresponding sensor, 
actuator and related electrical wiring, and the 
repair or replace.

5. After repair or replacement, recheck with the 

ohmmeter to confirm that the repair or 
replacement has corrected the problem.

Engine-ECU <M/T> or Engine-CVT-ECU <CVT> Harness Side Connector Terminal 
Arrangement

AK402726

61

46

31

64

49

19
34

50

51
6665

36

21

35

20

47

48
6362

33

18

32

17

58

43

28

44

45
6059

30

1615

29

14

41

42
5756

27

12

13

26

11

53

38

23

8

39

40

54

55

24

9

L

25

10

37
52

22

7

5

3

1

6

4

2

93

71

72

75

73

76

74

92

77

98

83

95 94

R

96

97

80

78

79

81

82

99

86

84

85

107
122

108
123

109
124

110
125

111
126

112
127

113
128

114
129

115
130

116
131

117
132

118
133

119
134

120
135

121
136

101100

102

103

104

105

106

87

88

919089

A-114

A-08

AG

Engine-ECU <M/T> or Engine-CVT-ECU <CVT>

 Harness Side Connector 

Terminal 
No.

Inspection item

Normal condition (Check condition)

5 

− 92

EGR valve (A) <CVT>

20 

− 24 Ω (at 20°C)

6 

− 92

EGR valve (B) <CVT>

53 

− 92

EGR valve (C) <CVT>

54 

− 92

EGR valve (D) <CVT>

7 

− 22

Throttle valve control servo

0.3 

− 100 Ω (at 20°C)

8 

− 92

No. 1 injector

14 

− 15 Ω (at 20°C)

9 

− 92

No. 2 injector

23 

− 92

No. 3 injector

24 

− 92

No. 4 injector

14 

− 29

Engine coolant temperature sensor

14 

− 17 kΩ (When coolant temperature is −20°C)

5.1 

− 6.5 kΩ (When coolant temperature is 0°C)

2.1 

− 2.7 kΩ (When coolant temperature is 20°C)

0.9 

− 1.3 kΩ (When coolant temperature is 40°C)

0.48 

− 0.68 kΩ (When coolant temperature is 60°C)

0.26 

− 0.36 kΩ (When coolant temperature is 80°C)

Main

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TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-348

INSPECTION PROCEDURE USING 
OSCILLOSCOPE

M1131154501728

The output signals of the sensors and the conditions 
of the actuation signals of the actuators can be 
inspected visually by observing the waveforms on 
the oscilloscope.

CAMSHAFT POSITION SENSOR AND 
CRANK ANGLE SENSOR
Measurement Method

1. Disconnect the camshaft position sensor 

connector and connect the special tool Test 
harness (MB991709) in between (All terminals 
should be connected).

2. Connect the oscilloscope special pattern pickup to 

camshaft position sensor terminal No. 2.

3. Disconnect the crank angle sensor intermediate 

connector and connect the special tool Test 
harness (MB991658) in between.

4. Connect the oscilloscope special patterns pickup 

to crank angle sensor terminal No. 2.

Alternate Method (Test harness not 
available)

1. Disconnect the engine-ECU connector or 

engine-CVT-ECU connector and connect the 
special tool Power plant ECU check harness 
(MB991987) in between.

2. Connect the oscilloscope special patterns pickup 

to engine-ECU <M/T> or engine-CVT-ECU 
<CVT> terminal No. 12 (When checking the 
camshaft position sensor signal wave pattern).

3. Connect the oscilloscope special patterns pickup 

to engine-ECU <M/T> or engine-CVT-ECU 
<CVT> terminal No. 13 (When checking the crank 
angle sensor signal wave pattern).

33 

− 56

Intake air temperature sensor

13 

− 17 kΩ (When intake air temperature is −20°C)

5.3 

− 6.7 kΩ (When intake air temperature is 0°C)

2.3 

− 3.0 kΩ (When intake air temperature is 20°C)

1.0 

− 1.5 kΩ (When intake air temperature is 40°C)

0.56 

− 0.76 kΩ (When intake air temperature is 60°C)

0.30 

− 0.42 kΩ (When intake air temperature is 80°C)

38 

− 92

Purge control solenoid valve

30 

− 34 Ω (at 20°C)

51 

− 92

Oxygen sensor heater (front)

5 

− 30 Ω (at 20°C)

52 

− 92

Oil feeder control valve

6.9 

− 7.9 Ω (at 20°C)

75 

− Body 

earth

Engine-ECU <M/T> or 
engine-CVT-ECU <CVT> earth

Continuity (2 

Ω or less)

76 

− Body 

earth
93 

− Body 

earth
108 

− 

Body 
earth
79 

− 92

Oxygen sensor heater (rear)

5 

− 30 Ω (at 20°C)

Terminal 
No.

Inspection item

Normal condition (Check condition)

1 2 3

3

2

1

AK304513

Special patterns
pick-up

Oscilloscope

AC

Camshaft position 
sensor connector

Crank angle sensor
intermediate
connector

Main

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TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-349

Standard Wave Pattern

Observation condition

Wave Pattern Observation Points

Check that cycle time T becomes shorter when the 
engine speed increases.

Examples of Abnormal Wave Patterns

•

Example 1

Cause of problem
Sensor interface malfunction

Wave pattern characteristics
Rectangular wave pattern is output even when 

the engine is not started.

•

Example 2

Cause of problem
Loose timing belt
Abnormality in sensor disk
Wave pattern characteristics
Wave pattern is displaced to the left or right.

Function

Special patterns

Pattern height

Low

Pattern selector

Display

Engine speed

Idle

AK204111AC

(V)

5

0

5

0

No. 1TDC

No. 3TDC

No. 4TDC

No. 2TDC

 time

Standard wave pattern

Crank angle
sensor output
wave pattern

Camshaft position
sensor output
wave pattern

  2 engine revolutions
(1 camshaft revolution)

TDC: Top dead centre

AK304525

AK203244

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