Mitsubishi Lancer Evolution IX. Manual — part 402
TROUBLESHOOTING
MULTIPORT FUEL INJECTION (MPI)
13A-83
FUNCTION
• The power supply to the oxygen sensor heater
(front) is controlled by the ON/OFF control of the
power transistor in the engine-ECU.
• Heating the oxygen sensor heater (front) enables
the oxygen sensor to provide good response
even when the exhaust emission temperature is
low.
TROUBLE JUDGMENT
Check Conditions
• The engine coolant temperature is 20°C or
higher.
• The oxygen sensor heater: (front) is ON.
• The engine speed of 50 r/min. or more.
• A/C relay: OFF
• Radiator fan: OFF
• The system voltage is 11 − 16 V.
Judging Criterion
• The heater current of oxygen sensor heater
(front) 0.2 A or less or 3.5 A or more for 4 sec-
onds.
PROBABLE CAUSES
• Failed oxygen sensor heater (front)
• Open/short circuit in oxygen sensor heater (front)
circuit or loose connector contact
• Failed engine-ECU
DIAGNOSIS PROCEDURE
STEP 1. Connector check: B-113 oxygen sensor
(front) connector
Q: Is the check result normal?
YES :
Go to Step 2 .
NO :
Repair or replace the connector.
STEP 2. Perform resistance measurement at
B-113 oxygen sensor (front) connector.
• Disconnect connector, and measure at sensor
side.
• Resistance between terminal No. 1 and No. 3.
OK: 4.5
− 8.0 Ω
Q: Is the check result normal?
YES :
Go to Step 3 .
NO :
Replace the oxygen sensor (front).
AK305011
1
2
3
4
AB
Connector : B-113
Harness side
connector
B-113(B)
Oxygen sensor(front)
AK305011
1
2
3
4
AB
Connector : B-113
Harness side
connector
B-113(B)
Oxygen sensor(front)
TROUBLESHOOTING
MULTIPORT FUEL INJECTION (MPI)
13A-84
STEP 3. Perform voltage measurement at B-113
oxygen sensor (front) connector.
• Disconnect connector, and measure at harness
side.
• Ignition switch: "ON"
• Voltage between terminal No. 1 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: B-12X engine control
relay connector
Q: Is the check result normal?
YES :
Check and repair harness between B-113
(terminal No. 1) oxygen sensor (front)
connector and B-12X (terminal No. 4)
engine control relay connector.
• Check power supply line for
open/short circuit.
NO :
Repair or replace the connector.
AK305011
1
2
3
4
AB
Connector : B-113
Harness side
connector
B-113(B)
Oxygen sensor(front)
AK305003
2
1
3
4
AB
Connector : B-12X
B-12X
Harness side
connector
Relay box’s
triangle marks
AK305011
1
2
3
4
AB
Connector : B-113
Harness side
connector
B-113(B)
Oxygen sensor(front)
TROUBLESHOOTING
MULTIPORT FUEL INJECTION (MPI)
13A-85
STEP 5. Perform voltage measurement at C-121
engine-ECU connector.
• Measure engine-ECU terminal voltage.
• Ignition switch: "ON"
• Voltage between terminal No. 3 and earth.
OK: System voltage
Q: Is the check result normal?
YES :
Go to Step 8 .
NO :
Go to Step 6 .
STEP 6. Connector check: C-121 engine-ECU
connector
Q: Is the check result normal?
YES :
Go to Step 7 .
NO :
Repair or replace the connector.
AK501995
2
3
4
5
6
7
8
9
11
12
13
14
15
16
17
18
19
20
30
21
22
23
24
25
26
27
28
29
31
32
33
34
35
1
10
AB
Connector: C-121
C-121 (GR)
C-121 (GR)
Harness side connector
<L. H. drive vehicles>
<R. H. drive vehicles>
AK501995
2
3
4
5
6
7
8
9
11
12
13
14
15
16
17
18
19
20
30
21
22
23
24
25
26
27
28
29
31
32
33
34
35
1
10
AB
Connector: C-121
C-121 (GR)
C-121 (GR)
Harness side connector
<L. H. drive vehicles>
<R. H. drive vehicles>
TROUBLESHOOTING
MULTIPORT FUEL INJECTION (MPI)
13A-86
STEP 7. Check harness between B-113 (terminal
No. 3) oxygen sensor connector and C-121
(terminal No. 3) engine-ECU connector.
• Check earthing line for open/short circuit.
Q: Is the check result normal?
YES :
Replace the engine-ECU.
NO :
Repair the damaged harness wire.
STEP 8. Connector check: C-121 engine-ECU
connector
Q: Is the check result normal?
YES :
Go to Step 9 .
NO :
Repair or replace the connector.
AK305011
1
2
3
4
AB
Connector : B-113
Harness side
connector
B-113(B)
Oxygen sensor(front)
AK501995
2
3
4
5
6
7
8
9
11
12
13
14
15
16
17
18
19
20
30
21
22
23
24
25
26
27
28
29
31
32
33
34
35
1
10
AB
Connector: C-121
C-121 (GR)
C-121 (GR)
Harness side connector
<L. H. drive vehicles>
<R. H. drive vehicles>
AK501995
2
3
4
5
6
7
8
9
11
12
13
14
15
16
17
18
19
20
30
21
22
23
24
25
26
27
28
29
31
32
33
34
35
1
10
AB
Connector: C-121
C-121 (GR)
C-121 (GR)
Harness side connector
<L. H. drive vehicles>
<R. H. drive vehicles>
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст