Mitsubishi Colt Ralliart. Manual — part 29

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-70

TROUBLE JUDGMENT

Check Conditions

• After engine starts <M/T>

• Engine coolant temperature is 20°C or higher.

• While oxygen sensor heater is on <CVT>.

• Engine speed is approximately 50 r/min or more

<CVT>.

• Battery positive voltage is 11 − 16 V

Judgment Criterion

• Oxygen sensor heater currents has continued to

be 0.16 A or lower, or 5 A or higher for 4 seconds.

PROBABLE CAUSES

• Failed oxygen sensor heater

• Open/short circuit in oxygen sensor heater circuit

or loose connector contact

• Failed engine-ECU <M/T> or engine-CVT-ECU

<CVT>

DIAGNOSIS PROCEDURE

STEP 1. Connector check: A-122 oxygen sensor
connector

Q: Is the check result normal?

YES :

Go to Step 2 .

NO :

Repair or replace the connector.

STEP 2. Perform resistance measurement at
A-122 oxygen sensor connector.

• Disconnect connector, and measure at sensor

side.

• Resistance between terminals No. 3 and No. 4.

OK: 5

− 30 Ω (at 20C°)

Q: Is the check result normal?

YES :

Go to Step 3 .

NO :

Replace oxygen sensor.

STEP 3. Perform voltage measurement at A-122
oxygen sensor connector.

• Disconnect connector, and measure at harness

side.

• Ignition switch: ON

• Voltage between terminal No. 3 and earth.

OK: System voltage

Q: Is the check result normal?

YES :

Go to Step 5 .

NO :

Go to Step 4 .

AK402012

2 1
4 3

Connector: A-122

A-122 (G)

AC

Oxygen sensor (front)

A-122 Harness side

connector

AK402012

2 1
4 3

Connector: A-122

A-122 (G)

AC

Oxygen sensor (front)

A-122 Harness side

connector

AK402012

2 1
4 3

Connector: A-122

A-122 (G)

AC

Oxygen sensor (front)

A-122 Harness side

connector

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-71

STEP 4. Connector check: B-106 engine control
relay connector

Q: Is the check result normal?

YES :

Check intermediate connector A-17 and

B-122, and repair if necessary. If
intermediate connectors are normal, check
and repair harness between A-122 (terminal
No. 3) oxygen sensor connector and B-106
(terminal No. 4) engine control relay
connector.

• Check power supply line for

open/short circuit.

NO :

Repair or replace the connector.

STEP 5. Perform voltage measurement at A-114
engine-ECU connector or engine-CVT-ECU
connector.

• Disconnect engine-ECU connector or

engine-CVT-ECU connector, and connect special
tool power plant ECU check harness
(MB991987), and then measure the voltage on
the check connector.

• Ignition switch: ON

• Voltage between terminal No. 51 and earth.

OK: System voltage

Q: Is the check result normal?

YES :

Go to Step 8 .

NO :

Go to Step 6 .

3

2

1

4

AK402060

B-106
J/B side
connector

B-106

Connector: B-106
J/B (front side)

AC

AK402012

2 1
4 3

Connector: A-122

A-122 (G)

AC

Oxygen sensor (front)

A-122 Harness side

connector

AK402745

6

4

2

5

3

1

9

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L

AE

A-114

Connector:

A-114

Engine-ECU <M/T> or
engine-CVT-ECU <CVT>

Battery

A-114 Special tool power plant ECU check
harness

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-72

STEP 6. Connector check: A-114 engine-ECU
connector or engine-CVT-ECU connector

Q: Is the check result normal?

YES :

Go to Step 7 .

NO :

Repair or replace the connector.

STEP 7. Check harness between A-122 (terminal
No. 4) oxygen sensor connector and A-114
(terminal No. 51) engine-ECU connector or
engine-CVT-ECU connector.

• Check earthing line for open/short circuit.

Q: Is the check result normal?

YES :

Replace engine-ECU <M/T> or

engine-CVT-ECU <CVT>.

NO :

Repair the damaged harness wire.

AK402745

6

4

2

5

3

1

9

7

8

10

11

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62

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64

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66

L

AD

A-114

Connector:

A-114

Harness side connector

Engine-ECU <M/T> or
engine-CVT-ECU <CVT>

Battery

AK402012

2 1
4 3

Connector: A-122

A-122 (G)

AC

Oxygen sensor (front)

A-122 Harness side

connector

AK402745

6

4

2

5

3

1

9

7

8

10

11

12

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66

L

AD

A-114

Connector:

A-114

Harness side connector

Engine-ECU <M/T> or
engine-CVT-ECU <CVT>

Battery

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-73

STEP 8. Connector check: A-114 engine-ECU
connector or engine-CVT-ECU connector

Q: Is the check result normal?

YES :

Go to Step 9 .

NO :

Repair or replace the connector.

STEP 9. Check harness between A-122 (terminal
No. 3) oxygen sensor connector and B-106
(terminal No. 4) engine control relay connector.

NOTE: Before checking harness, check intermediate
connector A-17 and B-112, and repair if necessary.

• Check power supply line for damage.

Q: Is the check result normal?

YES :

Go to Step 10 .

NO :

Repair the damaged harness wire.

AK402745

6

4

2

5

3

1

9

7

8

10

11

12

13

14

15

16

17

18

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66

L

AD

A-114

Connector:

A-114

Harness side connector

Engine-ECU <M/T> or
engine-CVT-ECU <CVT>

Battery

AK402012

2 1
4 3

Connector: A-122

A-122 (G)

AC

Oxygen sensor (front)

A-122 Harness side

connector

3

2

1

4

AK402060

B-106
J/B side
connector

B-106

Connector: B-106
J/B (front side)

AC

Main

Index

Group

TOC