Mitsubishi L200. Manual - part 127

TROUBLESHOOTING

DIESEL FUEL

13A-304

DIAGNOSIS PROCEDURE

STEP 1. Connector check: A-143 fuel filter 
pressure switch connector

Q: Is the check result normal?

YES : 

Go to Step 2 .

NO : 

Repair or replace the connector.

STEP 2. Check the fuel filter pressure switch 
itself.
Check the fuel filter pressure switch itself (Refer to 
GROUP 13B 

− Fuel Filter − Fuel Filter Inspection ).

Q: Is the check result normal?

YES : 

Replace the fuel filter body.

NO : 

Go to Step 3 .

STEP 3. Perform voltage measurement at A-143 
fuel filter pressure switch 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 7 .

NO : 

Go to Step 4 .

STEP 4. Connector check: C-103 engine-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 5 .

NO : 

Repair or replace the connector.

AK700919

1

2

AC

Connector: A-143

A-143 (B)

Harness side
connector

AK700919

1

2

AC

Connector: A-143

A-143 (B)

Harness side
connector

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-305

STEP 5. Check harness between A-143 (terminal 
No. 1) fuel filter pressure switch connector and 
C-103 (terminal No. 110) engine-ECU connector.

• Check output line for open/short circuit.

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-542

.

a. Item 152: Fuel filter pressure switch

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 ).

NO : 

Replace the engine-ECU. When the engine-
ECU is replaced, write the chassis number 
(Refer to GROUP 00 

− Precautions Before 

Service 

− How to Perform Chassis Number 

Writing ). After replacing the engine-ECU, 
register the injector identification code and 
learn fuel injection (Refer to GROUP 00 

− 

Precautions Before Service 

− What The 

Common Rail Engine Learns ).

STEP 7. Perform resistance measurement at A-
143 fuel filter pressure switch 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 8 .

NO : 

Check and repair harness between A-143 

(terminal No. 2) fuel filter pressure switch 
connector and body earth.

• Check earthing line for open circuit 

and damage.

AK700919

1

2

AC

Connector: A-143

A-143 (B)

Harness side
connector

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

AK700919

1

2

AC

Connector: A-143

A-143 (B)

Harness side
connector

TROUBLESHOOTING

DIESEL FUEL

13A-306

STEP 8. Connector check: C-103 engine-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-143 (terminal 
No. 1) fuel filter pressure switch connector and 
C-103 (terminal No. 110) engine-ECU connector.

• Check output line for damage.

Q: Is the check result normal?

YES : 

Replace the fuel filter.

NO : 

Repair the damaged harness wire.

Code No. P1277: Fuel Filter Freeze <Vehicles with fuel filter pressure switch>

FUNCTION

• The engine-ECU estimates that the fuel filter is 

freezing, using the input signal from the each 
sensor.

• When storing this diagnosis code, the engine-

ECU blinks the glow lamp.

TROUBLE JUDGMENT

Check Conditions

• During steady driving

• Fuel temperature is lower than specified temper-

ature

• Engine coolant temperature is lower than speci-

fied temperature

AKA00090

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144

C-103 (B)

C-103 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-103

AB

AK700919

1

2

AC

Connector: A-143

A-143 (B)

Harness side
connector

AKA00090

101

102

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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-307

Judgment Criteria

• Determination of clogged fuel filter

• Fuel pressure hunting occurs more than certain 

degree, or difference more than certain degree 
exists between target fuel pressure and actual 
fuel pressure

PROBABLE CAUSE

• Fuel filter Freezing

DIAGNOSIS PROCEDURE

STEP 1. Reconfirmation of M.U.T.-III diagnosis 
code after warming up the engine

Q: Is any other diagnosis code than P1276 output?

YES : 

Inspection chart for diagnosis code (Refer 

to ).

NO : 

Check end.

Code No. P1298: Variable Geometry Turbocharger Control System Malfunction (high pressure) 
<Euro5>

FUNCTION

• The engine-ECU controls the duty ratio of the 

variable geometry control solenoid valve so that 
the actual boost pressure can become the target 
boost pressure.

TROUBLE JUDGMENT

Check Condition

• Engine is running

Judgment Criterion

• Actual boost pressure is higher than target boost 

pressure by more than 6.7 kPa

PROBABLE CAUSES

• Failed variable geometry turbocharger control 

system

• Failed engine-ECU

DIAGNOSTIC PROCEDURE

STEP 1. Check the turbocharger supercharging 
pressure.

• Check the turbocharger supercharging pressure 

(refer to GROUP 15 

− On-vehicle Service − Tur-

bocharger Supercharging Pressure Check ).

Q: Is the check result normal?

YES : 

Go to Step 2 .

NO : 

Repair the variable geometry turbocharger 
control system.

STEP 2. M.U.T.-III diagnosis code.

• After clearing the diagnosis code through M.U.T.-

III, start the engine and confirm whether the diag-
nosis code is output.

Q: Is the diagnosis code set?

YES : 

Replace the engine-ECU. When the engine-

ECU is replaced, write the chassis number 
(Refer to GROUP 00 

− Precautions Before 

Service 

− How to Perform Chassis Number 

Writing ). After replacing the engine-ECU, 
register the injector identification code and 
learn fuel injection (Refer to GROUP 00 

− 

Precautions Before Service 

− What The 

Common Rail Engine Learns ). After 
registering the injector identification code, 
carry out the forcible DPF regeneration. 
(Refer to GROUP 17 

− Emission Control − 

Diesel Particulate Filter (DPF) System 

− 

Forcible DPF Regeneration ).

NO : 

Intermittent malfunction (Refer to GROUP 
00 

− How to Use Troubleshooting/

Inspection Service Points 

− How to Cope 

with Intermittent Malfunctions ).

Code No. P1299: Variable Geometry Turbocharger Control System Malfunction (low pressure) 
<Euro5>

FUNCTION

• The engine-ECU controls the duty ratio of the 

variable geometry control solenoid valve so that 
the actual boost pressure can become the target 
boost pressure.

TROUBLE JUDGMENT

Check Condition

• Engine is running