Mitsubishi Colt Ralliart. Manual - part 729

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-241

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosis

• Using M.U.T.-III, perform CAN busline diagnosis.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the CAN busline (Refer to GROUP 
54D 

− Troubleshooting − CAN Bus 

Diagnosis Table 

P.54D-13

). After repairing 

the CAN busline, go to Step 6.

STEP 2. M.U.T.-III other system diagnosis codes

• Check whether diagnosis codes is output from 

meter-A/C-ECU.

Q: Is the diagnosis code output?

YES : 

Perform troubleshooting of the air 

conditioning system (Refer to GROUP 55B 
−Troubleshooting 

P.55B-3

 ).

NO : 

Go to Step 3.

STEP 3. M.U.T.-III other system diagnosis codes
Check whether the diagnosis code U1110: A/C-ECU 
time-out is output from the following ECU having 
CAN communication with meter-A/C-ECU.

• ETACS-ECU

Q: Is the diagnosis code output?

YES : 

Go to Step 4.

NO : 

Go to Step 5.

STEP 4. M.U.T.-III diagnosis code
Reconfirm whether the diagnosis code is output from 
engine-ECU.

1. Erase the diagnosis code being output.
2. Ignition switch: LOCK (OFF) to ON
3. Confirm whether the diagnosis code is output.

Q: Is the diagnosis code output?

YES : 

Replace the A/C-ECU, and then go to Step 

6.

NO : 

Intermittent malfunction in the CAN bus-line 
between the engine-ECU and 
meter-A/C-ECU (Refer to GROUP 00 

− How 

to use Troubleshooting/Inspection Service 
Points 

− How to Cope with Intermittent 

Malfunctions 

P.00-13

).

STEP 5. M.U.T.-III diagnosis code

• Reconfirm whether the diagnosis code is output 

from engine-ECU.

1. Erase the diagnosis code being output.
2. Ignition switch: LOCK (OFF) to ON
3. Confirm whether the diagnosis code is output.

Q: Is the diagnosis code output?

YES : 

Replace engine-ECU, and then go to Step 

6.

NO : 

Intermittent malfunction in the CAN bus-line 
between the engine-ECU and 
meter-A/C-ECU (Refer to GROUP 00 

− How 

to use Troubleshooting/Inspection Service 
Points 

− How to Cope with Intermittent 

Malfunctions 

P.00-13

).

STEP 6. M.U.T.-III diagnosis code

• Reconfirm whether the diagnosis code is output 

from engine-ECU.

1. Erase the diagnosis code being output.
2. Ignition switch: LOCK (OFF) to ON
3. Confirm whether the diagnosis code is output.

Q: Is the diagnosis code output?

YES : 

Go to Step 1.

NO : 

Check end.

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-242

SYMPTOM PROCEDURES

Inspection Procedure 1: Communication with Engine-ECU is Not Possible

OPERATION

• Data is communicated between diagnosis con-

nector output terminal (terminal No. 7) and 
engine-ECU (terminal No. 121).

COMMENT ON TROUBLE SYMPTOM

• The problem may probably be traced to 

engine-ECU power circuit or earth circuit.

PROBABLE CAUSES

• Open/short circuit in or damage to the 

engine-ECU power circuit

• Between engine-ECU and diagnosis connector 

for open/short circuit or damage

• Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check engine start.

Q: Does engine start?

YES : 

Go to Step 2 .

NO : 

Check engine-ECU power source, engine 
control relay, and ignition switch-IG1 system 
(Refer to Inspection Procedure 21 

P.13B-282

).

AK402806

1 2 3 4 5 6

12

11

10

1516

14

13

9

7 8

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

B-32 

MU803797

20

121

7

B-41

Diagnosis Connector Circuit

AD

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: Viole

  P: Purple

t

A-08

Engine-ECU

Diagnosis connector

O-L

O-L

Main

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TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-243

STEP 2. Connector check: A-08 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 3 .

NO : 

Repair or replace.

STEP 3. Check harness between B-32 (terminal 
No. 7) diagnosis connector and A-08 (terminal 
No. 121) engine-ECU connector.

NOTE: Before checking harness, check intermediate 
connector B-41 and repair if necessary.

• Check signal line for open/short circuit or dam-

age.

Q: Is the check result normal?

YES : 

Go to Step 4 .

NO : 

Repair.

STEP 4. Check the trouble symptom.

Q: Does trouble symptom recur?

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

AK403279

1 2 3 4 5 6

12

11

10

1516

14

13

9

7 8

AC

Harness side connector

Connector: B-32

B-32(B)

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

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-244

Inspection Procedure 2: The Engine Warning Lamp Does Not Illuminate Right after the Ignition Switch 
is Turned to the "ON" Position

COMMENT ON TROUBLE SYMPTOM

• On the combination meter, engine warning lamp 

illuminates for 5 seconds right after ignition switch 
is turned ON.

• If engine warning lamp does not illuminate right 

after ignition switch is turned ON, the failure is 
possibly caused by malfunction of engine warn-
ing lamp, open or short in the combination meter 
circuits and so on.

PROBABLE CAUSES

• Failed engine warning lamp

• Open/short circuit in combination meter

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q: Is the diagnosis code output?

YES : 

Inspection chart for diagnosis codes (Refer 

to 

P.13B-18

).

NO : 

Go to Step 2 .

STEP 2. Check the trouble symptoms.

Q: Does trouble system persist?

YES : 

Replace combination meter assembly.

NO : 

Intermittent malfunction (Refer to GROUP 
00 

− How to Use 

Troubleshooting/Inspection Service Points 

− 

How to Cope with Intermittent Malfunctions 

P.00-13

).

Inspection Procedure 3: The Engine Warning Lamp Remains Illuminating and Never Goes Out

COMMENT ON TROUBLE SYMPTOM

• Engine-ECU has possibly detected the problem. 

Probable causes include combination meter cir-
cuit being shorted.

PROBABLE CAUSE

• Short circuit in combination meter

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q: Is the diagnosis code output?

YES : 

Inspection chart for diagnosis codes (Refer 

to 

P.13B-18

).

NO : 

Go to Step 2 .

STEP 2. Check the trouble symptoms.

Q: Does trouble system persist?

YES : 

Replace combination meter assembly.

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

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