Mitsubishi Colt Ralliart. Manual - part 688

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-77

STEP 9. Check harness between A-122 (terminal 
No. 3) oxygen sensor (front) connector and B-106 
(terminal No. 4) engine control relay connector.

NOTE: Before checking harness, check intermediate 
connectors A-17 and B-112 and repair if necessary.

• Check power supply line for damage.

Q: Is the check result normal?

YES : 

Go to Step 10 .

NO : 

Repair.

STEP 10. Check harness between A-122 (terminal 
No. 4) oxygen sensor (front) connector and A-114 
(terminal No. 51) engine-ECU connector.

• Check earthing line for damage.

Q: Is the check result normal?

YES : 

Go to Step 11 .

NO : 

Repair.

AK402087

Connector: A-122

Harness side 

connector

A-122(G)

AD

Oxygen sensor (front)

3

2

1

4

AK402084

J/B side 
connector

B-106

Connector: B-106
J/B (front side)

AC

AK402087

Connector: A-122

Harness side 

connector

A-122(G)

AD

Oxygen sensor (front)

AK402745

6

4

2

5

3

1

9

7

8

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

L

AF

A-114

Connector: 

A-114

Harness side connector

Engine-ECU

Battery

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-78

STEP 11. M.U.T.-III diagnosis code

Q: Is the diagnosis code output?

YES : 

Replace engine-ECU.

NO : 

Intermittent malfunction (Refer to GROUP 
00 

− How to Use 

Troubleshooting/Inspection Service Points 

− 

How to Cope with Intermittent Malfunctions 

P.00-13

).

Code No. P0136: Oxygen Sensor (Rear) System

OPERATION

• The sensor signal is inputted to the engine-ECU 

(terminal No. 97) from the oxygen sensor (rear) 
output terminal (terminal No. 1).

• The oxygen sensor (rear) (terminal No. 2) is 

earthed with engine-ECU (terminal No. 98).

AK600607

3 4

2

1

R

92 93 94 95969798

77 78 79 808182838485868788899091

99

100

107 108 109 110 111112113114115116117118119120121
122 123 124 125126127128129130131132133134135136

101102103104105106

71 72

73 74

75 76

Oxygen sensor (rear)

AB

Oxygen Sensor (rear) Circuit

Y

GR

From engine control relay

4

2

3

1

98

97

B-53

A-08

Wire colour code
B: Black  LG: Light green  G: Green  L: Blue  W: White  Y: Yellow  SB: Sky blue  BR: Brown  O: Orange  GR: Gray
R: Red  P: Pink  V: Violet  PU: Purple

Engine-ECU

To engine-ECU

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-79

FUNCTION

• The oxygen sensor (rear) converts the concentra-

tion of oxygen in the exhaust emission into a volt-
age and inputs the signal to the engine-ECU.

• When the air-fuel ratio is richer than the theoreti-

cal air-fuel ratio, the oxygen sensor (rear) outputs 
a voltage of about 1 V. When it is leaner than the 
theoretical air-fuel ratio, it outputs a voltage of 
about 0 V.

• Based on this signal, the engine-ECU corrects 

the deviation in the signal that is output by the 
oxygen sensor (rear).

TROUBLE JUDGMENT

Check Conditions

• 3 minutes later from when engine starts

• For 5 seconds, engine coolant temperature is 

more than 80

°C.

• For 5 seconds, engine speed is more than 1,200 

r/min.

• The volume efficiency for 5 seconds is 50% or 

more.

Judgement Criterion

• When 5 V is applied to oxygen sensor (rear) out-

put line via register, engine-ECU-interface output 
voltage is more than 4.0 V.

PROBABLE CAUSES

• Failed oxygen sensor (rear)

• Open/short circuit and damage in oxygen sensor 

(rear) circuit or loose connector contact

• Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

• Refer to Data List Reference Table 

P.13B-335

.

a. Item No. 59: Oxygen sensor (rear)

Q: Is the check result normal?

YES : 

Intermittent malfunction (Refer to GROUP 

00 

− How to Use 

Troubleshooting/Inspection Service Points 

− 

How to Cope with Intermittent Malfunctions 

P.00-13

).

NO : 

Go to Step 2 .

STEP 2. Connector check: B-53 oxygen sensor 
(rear) connector

Q: Is the check result normal?

YES : 

Go to Step 3 .

NO : 

Repair or replace the connector.

AK402019

3

2

1

4

Oxygen sensor (rear)

Connector: B-53

B-53 Harness side connector

AC

B-53

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-80

STEP 3. Perform resistance measurement at B-53 
oxygen sensor (rear) connector.

• Disconnect connector, and measure at harness 

side.

• Resistance between terminal No. 2 and earth.

OK: Continuity (2 

Ω or less)

Q: Is the check result normal?

YES : 

Go to Step 7 .

NO : 

Go to Step 4 .

STEP 4. Connector check: A-08 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 5 .

NO : 

Repair or replace the connector.

AK402019

3

2

1

4

Oxygen sensor (rear)

Connector: B-53

B-53 Harness side connector

AC

B-53

AK402725

77

78

79

80

81

82

83

84

92

93

94

95

96

97

98

99

85

86

87

88

89

90

91

100

101

102

103

104

105

106

115

116

117

118

119

120

121

107

108

109

110

111

112

113

114

130

131

132

133

134

135

136

122

123

124

125

126

127

128

129

72 71

74 73

76 75

R

AI

A-08

Connector: 

A-08

A-08 Special tool power plant ECU check 
harness

Engine-ECU

Battery

Main

Index

Group

TOC