Mitsubishi L200. Manual - part 173

TROUBLESHOOTING

DIESEL FUEL

13A-488

• Failed engine control relay

• Damaged harness (Open circuit between engine-

ECU and engine control relay, engine control 
relay and relay box, engine-ECU and earth, and 
open circuit between engine-ECU and J/B)

• Damaged connector (Engine-ECU connector, 

diagnosis connector)

• Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check battery voltage.

• Measure battery voltage during cranking.

OK: 8 V or more

Q: Is the check result normal?

YES : 

Go to Step 2 .

NO : 

Check battery (Refer to GROUP 54A 

− 

Battery 

− On-vehicle Service − Battery test 

).

STEP 2. Check engine control relay itself.

• Check engine control relay itself (Refer to 

P.13A-

594

).

Q: Is the check result normal?

YES : 

Go to Step 3 .

NO : 

Replace the engine control relay.

STEP 3. Connector check: A-20X engine control 
relay connector

Q: Is the check result normal?

YES : 

Go to Step 4 .

NO : 

Repair or replace.

STEP 4. Perform voltage measurement at A-20X 
engine control relay connector.

• Remove relay, and measure at harness side.

• Voltage between terminal No. 1 and earth, also 

between terminal No. 4 and earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 5 .

NO : 

Check intermediate connector A-115, and 

repair if necessary. If intermediate 
connector is normal, check and repair 
harness between A-20X (terminal No. 1 and 
terminal No. 4) engine control relay 
connector and battery.

STEP 5. Connector check: C-103 engine-ECU 
connector.

Q: Is the check result normal?

AK501321

2

1

3
4

Relay box's side 
connector

A-20X

Connector: A-20X

AC

AK501321

2

1

3
4

Relay box's side 
connector

A-20X

Connector: A-20X

AC

AKA00090

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C-103 (B)

C-103 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-103

AB

TROUBLESHOOTING

DIESEL FUEL

13A-489

YES : 

Go to Step 6 .

NO : 

Repair or replace.

STEP 6. Perform voltage measurement at C-103 
engine-ECU connector

• Disconnect connector, and measure at harness 

side.

• Voltage between terminal No. 118 and earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 7 .

NO : 

Repair the harness wire.

STEP 7. Perform voltage measurement at C-103 
engine-ECU connector.

• Disconnect connector, and measure at harness 

side.

• Short-circuit terminal No. 118 to earth. 

• Voltage between terminal No. 101 and earth also 

between terminal No. 102 and earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 8 .

NO : 

Repair the harness wire.

AKA00090

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C-103 (B)

C-103 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-103

AB

AKA00090

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C-103 (B)

C-103 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-103

AB

TROUBLESHOOTING

DIESEL FUEL

13A-490

STEP 8. Check for open circuit between engine-
ECU connector C-103 and earth.

• Disconnect connector, and measure at harness 

side.

• Check open circuit between terminal No. 145 and 

earth.

Q: Is the check result normal?

YES : 

Go to Step 9 .

NO : 

Repair the harness wire.

STEP 9. Connector check: C-103 engine-ECU 
connector.

Q: Is the check result normal?

YES : 

Go to Step 10 .

NO : 

Repair or replace.

AKA00090

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C-103 (B)

C-103 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-103

AB

AKA00090

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C-103 (B)

C-103 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-103

AB

TROUBLESHOOTING

DIESEL FUEL

13A-491

STEP 10. Check for open circuit between engine-
ECU connector C-103 and earth.

• Disconnect connector.

• Check open circuit between terminal No. 116 and 

earth also between terminal No. 117 and earth.

Q: Is the check result normal?

YES : 

Go to Step 11 .

NO : 

Repair the harness wire.

STEP 11. Perform voltage measurement at C-103 
engine-ECU connector.

• Disconnect connector, and measure at harness 

side.

• Ignition switch: ON 

• Voltage between terminal No. 104 and earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 12 .

NO : 

Check intermediate connector C-53 <L. H. 
drive vehicles> or C-35 <R. H. drive 
vehicles>, and repair if necessary. If 
intermediate connector is normal, check and 
repair harness between C-103 (terminal No. 
104) engine-ECU connector and C-208 J/B 
connector.

STEP 12. Check the trouble symptoms.

Q: Does trouble symptom persist?

AKA00090

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C-103 (B)

C-103 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-103

AB

AKA00090

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C-103 (B)

C-103 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-103

AB