Mitsubishi Grandis. Manual - part 713

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-103

TROUBLE JUDGMENT

Check Conditions

• 60 seconds have elapsed since the previous 

monitoring started.

• Engine coolant temperature is 20°C or higher.

• While cylinder 2, 3 oxygen sensor (rear) heater is 

on.

• Battery positive voltage is 11 − 16 V.

Judgment Criterion

• Cylinder 2, 3 oxygen sensor (rear) heater 

currents have continued to be 0.16 A or lower, or 
5.0 A or higher for 4 seconds.

PROBABLE CAUSE

• Failed cylinder 2, 3 oxygen sensor (rear) heater

• Open/short circuit in cylinder 2, 3 oxygen sensor 

(rear) heater circuit or loose connector contact

• Failed engine-ECU <M/T>

• Failed engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-18 cylinder 2, 3 
oxygen sensor (rear) connector

Q: Is the check result normal?

YES : 

Go to Step 2 .

NO : 

Repair or replace.

STEP 2. Perform resistance measurement at B-18 
cylinder 2, 3 oxygen sensor (rear) connector.

• Disconnect connector, and measure at sensor 

side.

• Resistance between terminal No. 1 and No. 3.

OK: 11 

− 18 Ω

Q: Is the check result normal?

YES : 

Go to Step 3 .

NO : 

Replace cylinder 2, 3 oxygen sensor (rear).

AK300977

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2

3

4

AC

Connector: B-18

Harness side 
connector

B-18 (B)

Cylinder 2, 3
oxygen sensor
(rear)

AK300977

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2

3

4

AC

Connector: B-18

Harness side 
connector

B-18 (B)

Cylinder 2, 3
oxygen sensor
(rear)

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-104

STEP 3. Perform voltage measurement at B-18 
cylinder 2, 3 oxygen sensor (rear) 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-15X engine control 
relay connector

Q: Is the check result normal?

YES : 

Check intermediate connector C-116, and 

repair if necessary. If intermediate 
connector is normal, check and repair 
harness between B-18 (terminal No. 1) 
cylinder 2, 3 oxygen sensor (rear) connector 
and B-15X (terminal No. 1) engine control 
relay connector.

• Check power supply line for 

open/short circuit.

NO : 

Repair or replace.

AK300977

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2

3

4

AC

Connector: B-18

Harness side 
connector

B-18 (B)

Cylinder 2, 3
oxygen sensor
(rear)

AK300967

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1

3

4

AC

Harness side
connector

B-15X

Connector: B-15X

Relay box’s
triangle marks

AK300977

1

2

3

4

AC

Connector: B-18

Harness side 
connector

B-18 (B)

Cylinder 2, 3
oxygen sensor
(rear)

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-105

STEP 5. Perform voltage measurement at C-110 
engine-ECU <M/T> connector or engine-A/T-ECU 
<A/T>.

• Measure engine-ECU <M/T> or engine-A/T-ECU 

<A/T> terminal voltage.

• Ignition switch: ON

• Voltage between terminal No. 18 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-110 engine-ECU 
<M/T> connector or engine-A/T-ECU <A/T> 
connector

Q: Is the check result normal?

YES : 

Go to Step 7 .

NO : 

Repair or replace.

AK305618AB

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Connector: C-110

<L.H. drive vehicles>

<R.H. drive vehicles>

C-110 (GR)

C-110 (GR)

Harness side connector

AK305618AB

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Connector: C-110

<L.H. drive vehicles>

<R.H. drive vehicles>

C-110 (GR)

C-110 (GR)

Harness side connector

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-106

STEP 7. Check harness between B-18 (terminal 
No. 3) cylinder 2, 3 oxygen sensor (rear) 
connector and C-110 (terminal No. 18) 
engine-ECU <M/T> connector or engine-A/T-ECU 
<A/T> connector.

• Check earthing line for open/short circuit.

Q: Is the check result normal?

YES : 

Replace engine-ECU <M/T> or 

engine-A/T-ECU <A/T>.

NO : 

Repair.

STEP 8. Connector check: C-110 engine-ECU 
<M/T> connector or engine-A/T-ECU <A/T> 
connector

Q: Is the check result normal?

YES : 

Go to Step 9 .

NO : 

Repair or replace.

AK300977

1

2

3

4

AC

Connector: B-18

Harness side 
connector

B-18 (B)

Cylinder 2, 3
oxygen sensor
(rear)

AK305618AB

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Connector: C-110

<L.H. drive vehicles>

<R.H. drive vehicles>

C-110 (GR)

C-110 (GR)

Harness side connector

AK305618AB

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Connector: C-110

<L.H. drive vehicles>

<R.H. drive vehicles>

C-110 (GR)

C-110 (GR)

Harness side connector