Mitsubishi Colt Ralliart. Manual — part 27

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-62

Code No. P0130: Oxygen Sensor (Front) System

OPERATION

• The sensor signal is inputted to the engine-ECU

<M/T> or engine-CVT-ECU <CVT> (terminal No.
34) from the oxygen sensor output terminal (ter-
minal No. 1).

• The oxygen sensor (front) (terminal No. 2) is

earthed with engine-ECU <M/T> or
engine-CVT-ECU <CVT> (terminal No. 49).

FUNCTION

• The oxygen sensor converts the concentration of

oxygen in the exhaust emission into a voltage
and inputs the signal to the engine-ECU <M/T> or
engine-CVT-ECU <CVT>.

• When the air-fuel ratio is richer than the theoreti-

cal air-fuel ratio, the oxygen sensor outputs a
voltage of about 1 V. When it is leaner than the
theoretical air-fuel ratio, it outputs a voltage of
about 0 V.

• In response to the signal, the engine-ECU <M/T>

or engine-CVT-ECU <CVT> controls the fuel
infection amount so that the air-fuel ratio can be
equivalent to the theoretical air-fuel ratio.

TROUBLE JUDGMENT

Check Conditions

• Above 5 minutes later after the engine has

started up.

• The engine coolant temperature is above 82°C

for 5 seconds or longer <M/T>.

• The engine speed is above 1,200 r/min for 5 sec-

onds or longer <M/T>.

AK503587

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52 53 54 555657585960616263646566

38 39 404142434445464748495051

22 23 24 252627282930313233343536

7

5

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6

4

2

Oxygen sensor (front)

Y

GR

From engine control relay

3

2

4

1

49

34

A-122
MU802083

A-114

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

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

AC

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

Oxygen Sensor Circuit (front)

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-63

• The intake manifold pressure is above 20 kPa for

5 seconds or longer <M/T>.

• Oxygen sensor (front) output voltage is 0.5 V or

less <CVT>.

• The engine coolant temperature is approximately

80

°C or higher <CVT>.

• The engine speed is 1,200 r/min or more <CVT>.

• During the run at the constant speed on the flat

road <CVT>.

Judgment Criteria

• When 5 V is applied to oxygen sensor (front) out-

put line via register, engine-ECU-interface output
voltage is more than 4.0 V <M/T>.

• When a power voltage of 5 V is applied to the

oxygen sensor, the sensor output voltage is 4.0 V
or more <CVT>.

Check Conditions

• Engine speed is more than 1,200 r/min and is

less than 3,000 r/min <M/T>.

• The engine coolant temperature is above 50°C

<M/T>.

• The intake manifold pressure is more than 30

kPa and is less than 60 kPa <M/T>.

• Within the range of air-fuel ratio feedback opera-

tion <M/T>.

Judgment Criterion

• The oxygen sensor (front) sends "lean" and "rich"

signals alternately 6 times or less for 10 seconds
<M/T>.

PROBABLE CAUSES

• Failed oxygen sensor

• Open/short circuit in oxygen sensor circuit or

loose connector contact

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

<CVT>

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

• Refer to Data List Reference Table

P.13A-331

.

a. Item 11: Oxygen sensor (front)

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

P.00-13

).

NO :

Go to Step 2 .

STEP 2. Connector check: A-122 oxygen sensor
(front) connector

Q: Is the check result normal?

YES :

Go to Step 3 .

NO :

Repair or replace the connector.

STEP 3. Perform resistance measurement at
A-122 oxygen sensor (front) connector.

• Disconnect connector, and measure at harness

side.

• Resistance between terminal No. 2 and earth.

OK: Continuity (2

Ω or less)

Q: Is the check result normal?

YES :

Go to Step 7 .

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

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-64

STEP 4. Connector check: A-114 engine-ECU
connector or engine-CVT-ECU connector

Q: Is the check result normal?

YES :

Go to Step 5 .

NO :

Repair or replace the connector.

STEP 5. Check harness between A-122 (terminal
No. 2) oxygen sensor connector and A-114
(terminal No. 49) engine-ECU connector or
engine-CVT-ECU connector.

• Check earthing line for open circuit and damage.

Q: Is the check result normal?

YES :

Go to Step 6 .

NO :

Repair the damaged harness wire.

STEP 6. M.U.T.-III data list

• Refer to Data List Reference Table

P.13A-331

.

a. Item 11: Oxygen sensor (front)

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

P.00-13

).

NO :

Replace engine-ECU <M/T> or
engine-CVT-ECU <CVT>.

AK402745

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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

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4

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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-65

STEP 7. Perform voltage measurement at A-122
oxygen sensor connector.

• Use special tool test harness (MD991658) to con-

nect connector, and measure at pick-up harness.

• Engine: After warm-up

• Transmission: P range

• Voltage between terminal No. 2 and earth.

OK: 0.5 V or less

Q: Is the check result normal?

YES :

Go to Step 9 .

NO :

Go to Step 8 .

STEP 8. 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. 2) oxygen sensor connector
and A-114 (terminal No. 49) engine-ECU
connector or engine-CVT-ECU connector.

• Check output line for damage.

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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4

2

5

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