Mitsubishi L200. Manual — part 68
TROUBLESHOOTING
DIESEL FUEL
13A-68
FUNCTION
• The air flow sensor outputs pulse signal that var-
ies in accordance with the intake air volume.
• In response to the signal, the engine-ECU con-
trols EGR control, etc.
TROUBLE JUDGMENT
Check Conditions
• Battery positive voltage is 8 − 16 V
• 2 seconds later after the ignition switch has been
in "ON" position or the engine has started up.
Judgment Criterion
• The air flow sensor output voltage is 0.50 V or
less.
PROBABLE CAUSES
• Failed air flow sensor
• Open/short circuit or harness damage in air flow
sensor circuit or loose connector contact
• Failed engine-ECU
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III data list
• Refer to Data List Reference Table
.
a. Item 114: Air flow sensor
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 ).
NO :
Go to Step 2 .
STEP 2. Connector check: A-135 air flow sensor
connector
Q: Is the check result normal?
YES :
Go to Step 3 .
NO :
Repair or replace the connector.
STEP 3. Perform voltage measurement at A-135
air flow sensor connector.
• Disconnect connector, and measure at harness
side.
• Ignition switch: ON
• Voltage between terminal No. 5 and earth.
OK: System voltage
Q: Is the check result normal?
YES :
Go to Step 5 .
NO :
Go to Step 4 .
STEP 4. Connector check: A-20X engine control
relay connector
Q: Is the check result normal?
AKA00399
AB
Harness side
connector
A-135 (B)
Connector: A-135
AKA00399
AB
Harness side
connector
A-135 (B)
Connector: A-135
AK501321
2
1
3
4
Relay box's side
connector
A-20X
Connector: A-20X
AC
AKA00399
AB
Harness side
connector
A-135 (B)
Connector: A-135
TROUBLESHOOTING
DIESEL FUEL
13A-69
YES :
Check and repair harness between A-20X
(terminal No. 3) engine control relay
connector and A-135 (terminal No. 5) air
flow sensor connector.
• Check power supply for open/short
circuit.
NO :
Repair or replace the connector.
STEP 5. Perform resistance measurement at A-
135 air flow sensor connector.
• Disconnect connector, and measure at harness
side.
• Resistance between terminal No. 4 and earth.
OK: Continuity (2
Ω or less)
Q: Is the check result normal?
YES :
Go to Step 9 .
NO :
Go to Step 6 .
STEP 6. Connector check: C-103 engine-ECU
connector
Q: Is the check result normal?
YES :
Go to Step 7 .
NO :
Repair or replace the connector.
AKA00399
AB
Harness side
connector
A-135 (B)
Connector: A-135
AKA00090
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
146
147
148
149
150
151
152
153
154
155
156
157
158
117
145
116
144
C-103 (B)
C-103 (B)
<R.H. drive vehicles>
Harness side connector
<L.H. drive vehicles>
Connector: C-103
AB
TROUBLESHOOTING
DIESEL FUEL
13A-70
STEP 7. Check harness between A-135 (terminal
No. 4) air flow sensor connector and C-103
(terminal No. 155) engine-ECU connector.
• Check earthing line for damage.
Q: Is the check result normal?
YES :
Go to Step 8 .
NO :
Repair the damaged harness wire.
STEP 8. M.U.T.-III data list
• Refer to Data List Reference Table
.
a. Item 114: Air flow sensor
Q: Is the check result normal?
AKA00399
AB
Harness side
connector
A-135 (B)
Connector: A-135
AKA00090
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
146
147
148
149
150
151
152
153
154
155
156
157
158
117
145
116
144
C-103 (B)
C-103 (B)
<R.H. drive vehicles>
Harness side connector
<L.H. drive vehicles>
Connector: C-103
AB
AKA00399
AB
Harness side
connector
A-135 (B)
Connector: A-135
AKA00090
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
146
147
148
149
150
151
152
153
154
155
156
157
158
117
145
116
144
C-103 (B)
C-103 (B)
<R.H. drive vehicles>
Harness side connector
<L.H. drive vehicles>
Connector: C-103
AB
TROUBLESHOOTING
DIESEL FUEL
13A-71
YES :
Intermittent malfunction (Refer to GROUP
00
− How to Use Troubleshooting/
Inspection Service Points
− How to Cope
with Intermittent Malfunctions ).
NO :
Replace the engine-ECU. When the engine-
ECU is replaced, write the chassis number
(Refer to GROUP 00
− Precautions Before
Service
− How to Perform Chassis Number
Writing ). After replacing the engine-ECU,
register the injector identification code and
learn fuel injection (Refer to GROUP 00
−
Precautions Before Service
− What The
Common Rail Engine Learns ). After
registering the injector identification code,
the vehicle equipped with the DPF carries
out the forcible DPF regeneration. (Refer to
GROUP 17
− Emission Control − Diesel
Particulate Filter (DPF) System
− Forcible
DPF Regeneration ).
STEP 9. Perform voltage measurement at A-135
air flow sensor connector.
• Disconnect connector, and measure at harness
side.
• Voltage between terminal No. 3 and earth.
OK: 4.9
− 5.1 V
Q: Is the check result normal?
YES :
Go to Step 12 .
NO :
Go to Step 10 .
STEP 10. Connector check: C-103 engine-ECU
connector
Q: Is the check result normal?
YES :
Go to Step 11 .
NO :
Repair or replace the connector.
AKA00399
AB
Harness side
connector
A-135 (B)
Connector: A-135
AKA00090
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
146
147
148
149
150
151
152
153
154
155
156
157
158
117
145
116
144
C-103 (B)
C-103 (B)
<R.H. drive vehicles>
Harness side connector
<L.H. drive vehicles>
Connector: C-103
AB
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