Mitsubishi Colt Ralliart. Manual — part 31

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-78

STEP 5. Check harness between B-53 (terminal
No. 2) oxygen sensor (rear) connector and A-08
(terminal No. 98) engine-ECU connector or
engine-CVT-ECU connector.

• Check earthing line for open circuit and damage.

Q: Is the check result normal?

YES :

Go to Step 6 .

NO :

Repair the damaged harness wire.

STEP 6. M.U.T.-III data list

• Refer to Data List Reference Table

P.13A-331

.

a. Item 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 :

Replace the engine-ECU <M/T> or
engine-CVT-ECU <CVT>.

STEP 7. Perform voltage measurement at B-53
oxygen sensor (rear) connector.

• Use special tool test harness (MB991658) to con-

nect connector, and measure at pick-up harness.

• Engine: After warm-up

• Transmission: Neutral

• Voltage between terminal No. 1 and earth.

OK:

When the engine is 2,500 r/min, the output

voltage should repeat 0 to 0.8 V alternately

Q: Is the check result normal?

YES :

Go to Step 10 .

NO :

Go to Step 8 .

STEP 8. Check Oxygen sensor (rear) itself.

• Check oxygen sensor (rear) itself (Refer to

P.13A-362

).

Q: Is the check result normal?

YES :

Go to Step 9 .

NO :

Replace the oxygen sensor (rear).

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

AG

A-08

Connector:

A-08

Harness side connector

Battery

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

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) <4A9>

13A-79

STEP 9. Connector check: A-08 engine-ECU
connector or engine-CVT-ECU connector

Q: Is the check result normal?

YES :

Check and repair harness between B-53

(terminal No. 1) oxygen sensor (rear)
connector and A-08 (terminal No. 97)
engine-ECU connector or engine-CVT-ECU
connector.

• Check output line for short circuit.

NO :

Repair or replace the connector.

STEP 10. Perform voltage measurement at A-08
engine-ECU connector or engine-CVT-ECU
connector.

• Disconnect engine-ECU connector or

engine-CVT-ECU connector, and connect special
tool power plant ECU check harness
(MB991987), and then measure the voltage on
the check connector.

• Transmission: P range

• Engine: After warm-up

• Voltage between terminal No. 97 and earth.

OK:

When the engine is 2,500 r/min, the output

voltage should repeat 0 to 0.8 V alternately.

Q: Is the check result normal?

YES :

Go to Step 12 .

NO :

Go to Step 11 .

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

AG

A-08

Connector:

A-08

Harness side connector

Battery

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

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

AH

A-08

Connector:

A-08

A-08 Special tool power plant ECU check
harness

Battery

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

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-80

STEP 11. Connector check: A-08 engine-ECU
connector or engine-CVT-ECU connector

Q: Is the check result normal?

YES :

Check and repair harness between B-53

(terminal No. 1) oxygen sensor (rear)
connector and A-08 (terminal No. 97)
engine-ECU connector or engine-CVT-ECU
connector.

• Check output line for open circuit and

damage.

NO :

Repair or replace the connector.

STEP 12. Connector check: A-08 engine-ECU
connector or engine-CVT-ECU connector

Q: Is the check result normal?

YES :

Go to Step 6 .

NO :

Repair or replace the connector.

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

AG

A-08

Connector:

A-08

Harness side connector

Battery

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

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

AG

A-08

Connector:

A-08

Harness side connector

Battery

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

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-81

Code No. P0141: Oxygen sensor (Rear) Heater System

OPERATION

• Power is supplied to the heater power terminal

(terminal No. 4) of the oxygen sensor (rear) con-
nector from the engine control relay (terminal No.
4).

• The heater (terminal No. 3) of the oxygen sensor

(rear) connector is controlled by the power tran-
sistor in the engine-ECU <M/T> or
engine-CVT-ECU <CVT> (terminal No. 79).

FUNCTION

• The power supply to the oxygen sensor (rear)

heater is controlled by the ON/OFF control of the
power transistor in the engine-ECU <M/T> or
engine-CVT-ECU <CVT>.

• Heating the oxygen sensor (rear) heater enables

the oxygen sensor (rear) to provide good
response even when the exhaust emission tem-
perature is low.

AK402683

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

3

1

2

4

3

1

4

6

2

Oxygen sensor (rear)

4

2

3

1

79

Engine
control
relay

R

LG-R

B-106

A-08

B-108

B-112

Oxygen Sensor (rear) Heater Circuit

B-53

MU801446

1

1

R

Fusible link

16

20A

J/B

AC

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

To engine-ECU <M/T> or
engine-CVT-ECU <CVT>

To engine-ECU <M/T> or
engine-CVT-ECU <CVT>

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

Main

Index

Group

TOC