Mitsubishi L200. Manual - part 125

TROUBLESHOOTING

DIESEL FUEL

13A-296

TROUBLE JUDGMENT

Check Conditions

• Ignition switch is in "ON" position

• Except during the engine cranking period

• Battery positive voltage is 8 V or more

Judgment Criterion

• A capacitor in overcharge state (100 V or higher) 

is detected in an engine-ECU internal circuit.

PROBABLE CAUSE

• Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

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

III, ignition switch is "ON" position and confirm 
whether the diagnosis 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, 
the vehicle equipped with the DPF carries 
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. P1272: Pressure Limiter Malfunction

OPERATION

• Refer to Code No. P0003: Suction Control Valve 

Open 

P.13A-26

. <Euro 5>

• Refer to Code No. P0004: Suction Control Valve 

Battery Short 

P.13A-29

. <Euro 5>

• Refer to Code No. P0191: Rail Pressure Sensor 

Range/Performance Problem 

P.13A-143

.

• Refer to Code No. P0192: Rail Pressure Sensor 

Circuit Low Input 

P.13A-147

.

• Refer to Code No. P0193: Rail Pressure Sensor 

Circuit High Input 

P.13A-155

.

• Refer to Code No. P0628: Suction Control Valve 

Open 

P.13A-276

. <Except Euro 5>

• Refer to Code No. P0629: Suction Control Valve 

Battery Short 

P.13A-279

. <Except Euro 5>

FUNCTION

• The engine-ECU controls the fuel discharge rate 

using the suction control valve.

• The engine-ECU monitors the signals input from 

the rail pressure sensor.

• The engine-ECU checks whether the pressure 

limiter valve is open, based on changes in the 
signals input from the rail pressure sensor (rapid 
drop of pressure after it goes extremely high).

TROUBLE JUDGMENT

Check Conditions

• Battery positive voltage is 8 − 16 V

• Engine speed is 600 r/min or more

• 2 seconds later after the ignition switch has been 

in "ON" position or the engine has started up

• Rail pressure is normal

Judgment Criterion

• After a pressure higher than the pressure of the 

pressure limiter opening valve is detected, fuel 
leakage diagnosis (supply pump discharge rate 
excessive) is detected within the predetermined 
time.

PROBABLE CAUSES

• Failed suction control valve

• Failed fuel system

• Failed common rail assembly

• Open/short circuit or harness damage in suction 

control valve circuit or loose connector contact

• Failed engine-ECU

DIAGNOSIS PROCEDURE

NOTE: This diagnosis code is outputted for an air 
penetration in the fuel line of the supply pump due to 
lack of fuel. Therefore, bleed air from the fuel line 
after the fuel supply, and delete the diagnosis code 
through M.U.T.-III.

TROUBLESHOOTING

DIESEL FUEL

13A-297

STEP 1. M.U.T.-III diagnosis code

Q: Is any other diagnosis code than P1272 output?

YES : 

Inspection chart for diagnosis codes (Refer 

to 

P.13A-21

).

NO : 

Go to Step 2 .

STEP 2. Check the fuel filter contamination

Q: Is the check result normal?

YES : 

Go to Step 3 .

NO : 

Replace the fuel filter then replace the 
common rail assembly and fuel injection 
tubes.

STEP 3. Release the air from the fuel line.

• After releasing the air from the fuel line, continue 

idle operation for about five minutes and recheck 
for abnormal symptoms.

Q: Does trouble symptom persist?

YES : 

Replace the common rail assembly and 

common tubes.

NO : 

Go to Step 4 .

STEP 4. Check suction control valve itself

• Check suction control valve itself (Refer to 

P.13A-

596

).

Q: Is the check result normal?

YES : 

Go to Step 5 .

NO : 

Replace the suction control valve. After 
replacing the suction control valve, learn the 
supply pump (Refer to GROUP 00 

− 

Precautions Before Service 

− What The 

Common Rail Engine Learns ).

STEP 5. Connector check: C-103 engine-ECU 
connector and A-47 suction control valve 
connector

Q: Are the check results normal?

YES : 

Go to Step 6 .

NO : 

Repair or replace the connector.

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

AK503644

2

1

A-47 (GR)

Harness side 
connector

AB

Connector: A-47

TROUBLESHOOTING

DIESEL FUEL

13A-298

STEP 6. Check harness between C-103 (terminal 
No. 131) engine-ECU connector and A-47 
(terminal No. 1) suction control valve connector.

• Check output line for open/short circuit and dam-

age.

Q: Is the check result normal?

YES : 

Go to Step 7 .

NO : 

Repair the damaged harness wire.

STEP 7. Check harness between C-103 (terminal 
No. 146) engine-ECU connector and A-47 
(terminal No. 2) suction control valve connector.

• Check output line for open/short circuit and dam-

age.

Q: Is the check result normal?

YES : 

Go to Step 8 .

NO : 

Repair the damaged harness wire.

AKA00090

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116

144

C-103 (B)

C-103 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-103

AB

AK503644

2

1

A-47 (GR)

Harness side 
connector

AB

Connector: A-47

AKA00090

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

118

119

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146

147

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149

150

151

152

153

154

155

156

157

158

117

145

116

144

C-103 (B)

C-103 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-103

AB

AK503644

2

1

A-47 (GR)

Harness side 
connector

AB

Connector: A-47

TROUBLESHOOTING

DIESEL FUEL

13A-299

STEP 8. Perform output wave pattern 
measurement at A-47 suction control valve 
(Using an oscilloscope).

• Engine: Idling

• Connect the oscilloscope special patterns pickup 

to engine-ECU terminal No. 131 and earth.

OK: The waveform should show a pattern 
similar to the illustration of Inspection proce-
dure using an oscilloscope (Refer to 

P.13A-

586

).

Q: Is the check result normal?

YES : 

Go to Step 9 .

NO : 

Replace the engine-ECU then replace the 
common rail assembly and fuel injection 
tubes. 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, the vehicle 
equipped with the DPF carries out the 
forcible DPF regeneration. (Refer to 
GROUP 17 

− Emission Control − Diesel 

Particulate Filter (DPF) System 

− Forcible 

DPF Regeneration ).

STEP 9. Replace the common rail assembly and 
fuel injection tubes.

• After replacing the common rail assembly and 

common tubes, re-check the trouble symptoms

Q: Does trouble symptom persist?

YES : 

Replace the suction control valve. After 

replacing the suction control valve, learn the 
supply pump (Refer to GROUP 00 

− 

Precautions Before Service 

− What The 

Common Rail Engine Learns ).

NO : 

The check is end.

Code No. P1273: Supply Pump Insufficient Flow

OPERATION

• Refer to Code No. P0003: Suction Control Valve 

Open 

P.13A-26

. <Euro 5>

• Refer to Code No. P0004: Suction Control Valve 

Battery Short 

P.13A-29

. <Euro 5>

• Refer to Code No. P0335: Crank Angle Sensor 

System 

P.13A-184

.

• Refer to Code No. P0340: Camshaft Position 

Sensor System 

P.13A-192

.

• Refer to Code No. P0628: Suction Control Valve 

Open 

P.13A-276

. <Except Euro 5>

• Refer to Code No. P0629: Suction Control Valve 

Battery Short 

P.13A-279

. <Except Euro 5>

FUNCTION

• The engine-ECU controls the fuel discharge rate 

using the suction control valve.

• The engine-ECU monitors changes in the fuel 

discharge rate at each injection to detect a fault in 
one of the two plungers in the supply pump.

TROUBLE JUDGMENT

Check Condition

• Vehicle in steady and stable state (the difference 

from the last data of the objective common rail 
pressure is less than 3 MPa and that from the last 
data of the final fuel injection rate is less than 2 
mm

3

/st.

Judgment Criterion

• The inter-cylinder difference in pressure feed 

exceeds the predetermined value 500 times con-
secutively.

PROBABLE CAUSES

• Air penetration due to lack of fuel

AK503644

2

1

A-47 (GR)

Harness side 
connector

AB

Connector: A-47