Mitsubishi Colt Ralliart. Manual - part 719

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-201

Code No. P1602: Communication Malfunction (between Engine-ECU Main Processor and System LSI)

FUNCTION

• Engine-ECU checks the communication status 

for abnormal conditions.

TROUBLE JUDGMENT

Check Conditions

• Ignition switch is ON position.

Judgement Criteria

• The communication between Main microcom-

puter and system LSI is abnormal.

PROBALE CAUSE

• Failed engine-ECU <M/T>

DIAGNOSIS

STEP 1. Check the trouble symptoms.

Q: Does trouble symptom persist?

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

).

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-202

Code No. P1603: Battery Backup Circuit Malfunction

OPERATION

• Power is directly supplied to the engine-ECU (ter-

minal No. 82) from the battery.

FUNCTION

• The engine-ECU checks the open circuit of bat-

tery backup line.

TROUBLE JUDGMENT

Check Conditions

• Ignition switch is in "ON" position.

Judgment Criterion

• For 2 seconds, battery backup voltage is less 

than 6.

PROBABLE CAUSES

• Open/short circuit and damage in battery backup 

line circuit or loose connector contact

• Failed engine-ECU

AK402698

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

43

AE

Fusible link 

R

R-B

82

Battery
backup

Engine-ECU

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  P: Purple

10A

Battery Backup Circuit

A-08

19

B-112

J/B

B-108

1

1

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-203

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

• Temporarily place the ignition switch in "LOCK" 

(OFF) position, and 10 seconds after that, place it 
in "ON" position again.

Q: Is the diagnosis code P1603 set?

YES : 

Go to Step 2 .

NO : 

Intermittent malfunction (Refer to GROUP 
00 

− How to Use 

Troubleshooting/Inspection Service Points 

− 

How to Cope with Intermittent Malfunctions 

P.00-13

).

STEP 2. Perform voltage measurement at A-08 
engine-ECU connector.

• Disconnect connector, and measure at harness 

side.

• Ignition switch: ON

• Voltage between terminal No. 82 and earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 3 .

NO : 

Check intermediate connector B-108 and 

B-112, and repair if necessary. If 
intermediate connector is normal, check and 
repair harness between battery and A-08 
(terminal No. 82) engine-ECU connector.

• Check power supply line for 

open/short circuit.

STEP 3. Check harness between battery and A-08 
(terminal No. 82) engine-ECU connector.

NOTE:  Before checking harness, check intermedi-
ate connector B-108 and B-112, and repair if neces-
sary.

• Check power supply line for damage.

Q: Is the check result normal?

YES : 

Go to Step 4 .

NO : 

Repair the damaged harness wire.

AK402725

77

78

79

80

81

82

83

84

92

93

94

95

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85

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87

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91

100

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102

103

104

105

106

115

116

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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

AK402725

77

78

79

80

81

82

83

84

92

93

94

95

96

97

98

99

85

86

87

88

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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

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-204

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.

STEP 5. M.U.T.-III diagnosis code.

• Reconfirmation of diagnosis code.

Q: Is the diagnosis code set?

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

).

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