Mitsubishi Lancer Evolution IX. Manual — part 472

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-363

Inspection Procedure 31: Ignition Circuit System <R. H. drive vehicles>

1 2 3

1 2 3

1

2

3

4

AK501855

1 2 3
4 5 6

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

3132 33

34 35

1

10

LOCK

ACC

IG1

R

IG2

ST

Engine-ECU

Ignition coil 2

B-114

(MU802064)

Ignition coil 1

B-103

(MU802064)

2

1

1

3

3

2

11

12

Ignition switch

Battery

C-208

W

W

B

B

B

B-Y

B

B

B

B-G

2

1

10A

2

W

1

4

3

6

C-211

C-31

13

10

C-214

C-123

9

Ignition circuit

C-121

(MU803784)

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

AB

Spark
plug

8

20A

B-Y

B-W

B-R

J/B

B-Y

W-R

W-R

W-R

Relay
box

OFF

ON

Engine
control
system

Ignition
coil relay

B-10X

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-364

OPERATION

• The battery voltage is applied to the ignition coil

relay (terminal No. 2) from the ignition switch and
is earthed to the vehicle body from the ignition
coil relay (terminal No. 3).

• The battery voltage is applied to the ignition coil

relay (terminal No. 1) from the battery and is
earthed to the vehicle body from the ignition coil
(terminal No. 2).

• A power voltage of 12 V is applied to the ignition

coil output terminal (terminal No. 3) from the
engine-ECU (terminal No. 11 and No. 12).

FUNCTION

• When the engine-ECU makes the power transis-

tor in the unit be in "OFF" position, the battery
voltage in the unit is applied to the power transis-
tor unit, and that makes the power transistor unit
be in "ON" position. The engine-ECU makes the
power transistor in the unit be in "ON", and that
makes the power transistor unit be in "OFF" posi-
tion.

• In response to the signal from the engine-ECU,

the power transistor unit is in "ON" position. The
primary current is going to the ignition coil. When
the power transistor unit is in "OFF" position, the
primary current is interrupted and high voltage is
generated in the secondary coil.

PROBABLE CAUSES

• Failed ignition coil

• Failed ignition coil relay

• Failed spark plug

• Failed spark plug cable

• Open/short circuit in ignition primary circuit or

loose connector contact

• Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check spark plug cable itself.

• Check spark plug cable itself (Refer to GROUP

16

− Ignition System − On-vehicle Service

P.16-29

).

Q: Is the check result normal?

YES :

Go to Step 2 .

NO :

Replace the spark plug cable.

STEP 2. Check spark plug.

Q: Is the check result normal?

YES :

Go to Step 3 .

NO :

Replace the spark plug.

STEP 3. Connector check: B-103 and B-114
ignition coil connectors

Q: Is the check result normal?

YES :

Go to Step 4 .

NO :

Repair or replace the connector.

STEP 4. Check ignition coil itself.

• Check ignition coil itself (Refer to GROUP 16 −

Ignition System

− On-vehicle Service

P.16-28

).

Q: Is the check result normal?

YES :

Go to Step 5 .

NO :

Replace the ignition coil.

STEP 5. Perform voltage measurement at B-103
and B-114 ignition coil connectors.

• 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 12 .

NO :

Go to Step 6 .

AK305047

1

2

3

Connector : B-103, B-114

B-114(GR)

B-103(GR)

AB

Harness side
connector

AK305047

1

2

3

Connector : B-103, B-114

B-114(GR)

B-103(GR)

AB

Harness side
connector

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-365

STEP 6. Connector check: B-10X ignition coil
relay connector

Q: Is the check result normal?

YES :

Go to Step 7 .

NO :

Repair or replace the connector.

STEP 7. Check ignition coil relay.

• Check ignition coil relay (Refer to GROUP 16 −

Ignition System

− On-vehicle Service

P.16-28

).

Q: Is the check result normal?

YES :

Go to Step 8 .

NO :

Replace the ignition coil relay.

STEP 8. Perform voltage measurement at B-10X
ignition coil relay connector.

• Remove relay, and measure at relay box side.

• Ignition switch: "ON"

• Voltage between terminal No. 2 and earth.

OK: System voltage

Q: Is the check result normal?

YES :

Go to Step 10 .

NO :

Go to Step 9 .

STEP 9. Connector check: C-208 ignition switch
connector

Q: Is the check result normal?

YES :

Check intermediate connectors C-123,

C-211 and C-214, and repair if necessary. If
intermediate connectors are normal, check
and repair harness between C-208 (terminal
No. 2) ignition switch connector and B-10X
(terminal No. 2) ignition coil relay connector.

• Check power supply line for

open/short circuit.

NO :

Repair or replace the connector.

AK305279

2

1

3

4

Relay box's
triangle marks

AB

B-10X(B)

Harness side
connector

Connector: B-10X

AK305279

2

1

3

4

Relay box's
triangle marks

AB

B-10X(B)

Harness side
connector

Connector: B-10X

1

2

3

4

5

6

AK305448

Harness side
connector

Connector: C-208

C-208

AB

AK305279

2

1

3

4

Relay box's
triangle marks

AB

B-10X(B)

Harness side
connector

Connector: B-10X

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-366

STEP 10. Perform resistance measurement at
B-10X connector.

• Remove relay, and measure at relay box side.

• Resistance between terminal No. 3 and earth.

OK: 2

Ω or less

Q: Is the check result normal?

YES :

Go to Step 11 .

NO :

Check and repair harness between B-10X

(terminal No. 3) ignition coil relay connector
and body earth.

• Check earthing line for open circuit

and damage.

STEP 11. Perform voltage measurement at B-10X
ignition coil relay connector.

• Remove relay, and measure at relay box side.

• Voltage between terminal No. 1 and earth.

OK: System voltage

Q: Is the check result normal?

YES :

Check and repair harness between B-10X

(terminal No. 4) ignition coil relay connector
and B-103 (terminal No. 1) ignition coil
connector, also between B-10X (terminal
No. 4) ignition coil relay connector and
B-114 (terminal No. 1) ignition coil
connector.

• Check power supply line for

open/short circuit.

NO :

Check intermediate connector C-31 and

repair if necessary. If intermediate
connector is normal, check and repair
harness between B-10X (terminal No. 1)
ignition coil relay connector and battery.

• Check power supply line for

open/short circuit.

AK305279

2

1

3

4

Relay box's
triangle marks

AB

B-10X(B)

Harness side
connector

Connector: B-10X

AK305279

2

1

3

4

Relay box's
triangle marks

AB

B-10X(B)

Harness side
connector

Connector: B-10X

AK305047

1

2

3

Connector : B-103, B-114

B-114(GR)

B-103(GR)

AB

Harness side
connector