Mitsubishi Colt Ralliart. Manual - part 28

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-66

STEP 9. Perform voltage measurement at A-122 
oxygen sensor connector.

• Use special tool test harness (MB991658) to con-

nect connector, and measure at pick-up harness.

• Transmission: P range

• Engine: After warm-up

• Voltage between terminal No. 1 and earth.

OK:

When the engine is 2,500 r/min, the output 

voltage should repeat 0 to 0.8 V alternately.

Q: Is the check result normal?

YES : 

Go to Step 12 .

NO : 

Go to Step 10 .

STEP 10. Check oxygen sensor itself

• Check oxygen sensor itself (Refer to 

P.13A-362

).

Q: Is the check result normal?

YES : 

Go to Step 11 .

NO : 

Replace oxygen sensor.

STEP 11. Connector check: A-114 engine-ECU 
connector or engine-CVT-ECU connector

Q: Is the check result normal?

YES : 

Check and repair harness between A-122 

(terminal No. 1) oxygen sensor connector 
and A-114 (terminal No. 34) engine-ECU 
connector or engine-CVT-ECU connector.

• Check output line for open circuit.

NO : 

Repair or replace the connector.

AK402012

2 1
4 3

Connector: A-122

A-122 (G)

AC

Oxygen sensor (front)

A-122 Harness side

connector

AK402745

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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

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-67

STEP 12. 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.

• Transmission: P range

• Engine: After warm-up

• Voltage between terminal No. 34 and earth.

OK:

When the engine is 2,500 r/min, the output 

voltage should repeat 0 to 0.8 V alternately.

Q: Is the check result normal?

YES : 

Go to Step 14 .

NO : 

Go to Step 13 .

STEP 13. Connector check: A-114 engine-ECU 
connector or engine-CVT-ECU connector

Q: Is the check result normal?

YES : 

Check and repair harness between A-122 

(terminal No. 1) oxygen sensor connector 
and A-114 (terminal No. 34) engine-ECU 
connector or engine-CVT-ECU connector.

• Check output line for damage.

NO : 

Repair or replace the connector.

AK402745

6

4

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3

1

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66

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

AK402745

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4

2

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3

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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

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-68

STEP 14. Connector check: A-114 engine-ECU 
connector or engine-CVT-ECU connector

Q: Is the check result normal?

YES : 

Go to Step 6 .

NO : 

Repair or replace the connector.

AK402745

6

4

2

5

3

1

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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-69

Code No. P0135: Oxygen Sensor (Front) Heater System

OPERATION

• Power is supplied to the heater power terminal 

(terminal No. 3) of the oxygen sensor connector 
from the engine control relay (terminal No. 4).

• The heater (terminal No. 4) of the oxygen sensor 

connector is controlled by the power transistor in 
the engine-ECU <M/T> or engine-CVT-ECU 
<CVT> (terminal No. 51).

FUNCTION

• The power supply to the oxygen sensor heater is 

controlled by the ON/OFF control of the power 
transistor in the engine-ECU <M/T> or 
engine-CVT-ECU <CVT>.

• Heating the oxygen sensor heater enables the 

oxygen sensor to provide good response even 
when the exhaust emission temperature is low.

AK402681

3

1

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1 2

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1213

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8 9

L

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37
52 53 54 555657585960616263646566

38 39 404142434445464748495051

22 23 24 252627282930313233343536

7

5

3

1

6

4

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3

1

1

1

4

6

2

Oxygen sensor (front)

3

2

4

1

51

Engine
control
relay

R

LG-R

R

Fusible link

B-106

A-114

B-112

B-108

A-122

MU802083

Oxygen Sensor (front) Heater Circuit

16

20A

J/B

AD

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

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

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

A-17

4

R

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

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