Code No. P0093: Fuel Leak Problem

OPERATION

Refer to Code No. P0191: Rail Pressure Sensor Range/performance Problem .

FUNCTION

The engine-ECU monitors the signals input from the rail pressure sensor.
The engine-ECU controls the suction control valve so that necessary fuel pressure can be obtained before fuel injection.
The engine-ECU compares the fuel pressure immediately before fuel injection and the fuel pressure after injection to check whether. The pressure drop greatly exceeds the expected range determined based on fuel consumption. The engine-ECU detects fuel leaks in this way

TROUBLE JUDGMENT

Check Conditions

Battery positive voltage is 8 - 16 V.
2 seconds later after the ignition switch has been in "ON" position or the engine has started up.
The engine speed is 600 r/min or more.
Rail pressure sensor is normal.

Judgment Criterion

The fuel discharge rate of the supply pump continues to exceed its threshold value against the fuel injection rate.

FAIL-SAFE AND BACKUP FUNCTION

The rail pressure is controlled to be 100 MPa or less.
The fuel injection amount is restricted. (Output restriction)
The open angle of the accelerator pedal is restricted.
The throttle valve is closed. (Fixed opening degree)
The EGR control is stopped (fully closed).
The DPF regeneration is prohibited.
The AS&G control is prohibited.

PROBABLE CAUSES

Fuel leakage or fuel line blocked
Failed injector
Failed suction control valve
Failed rail pressure sensor
Harness damage in rail pressure sensor circuit or loose connector contact.
Failed fuel pressure limiter valve
Failed engine-ECU

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q. Is any other diagnosis code than P0093 set?

	Inspection chart for diagnosis codes (Refer to ).

	Go to Step 2.

STEP 2. Detection of fuel line leakage.

Check whether fuel is leaking from a high-pressure fuel line.

Q. Is the check result normal?

	Go to Step 3.

	Replace the parts of an abnormal location.

STEP 3. Release the air from the fuel line.

Repeat, more than 3 times, the cycle turning on the ignition switch and leaving it for more than 20 seconds. Operate the fuel pump in the fuel tank. Check there is no air at all in the fuel pipe.
After releasing the air from the fuel line, continue idle operation for about five minutes and recheck for trouble symptoms.

Q. Does the trouble symptom persist?

	Go to Step 4.

	The check is end.

STEP 4. Engine oil level check.

Use the oil level gauge to check that the amount of engine oil does not increase. Check there is no smell of oil.

Q. Are the check results normal?

	Go to Step 6.

	Go to Step 5.

STEP 5. Fuel leakage from injector check.

Connect the M.U.T.-III to run the engine at idle speed.
Carry out the actuator test item No.15, 16, 17 and 18 to stop the injector driving.

Q. Check whether there are the cylinders changing the engine conditions or not.

	Replace the injector not changing the engine conditions. After replacing the injector, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns <4N1> ).

	Replace the injector of each cylinder with the good one to check the recurrence of the malfunction. Find out the poor injector to replace it. After replacing the injector, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns <4N1> ).

STEP 6. Rail pressure sensor output signal check.

Wait for more than 5 minutes after turning off the engine to check there is no pressure in the common rail.
Check the M.U.T.-III for Data List Item No.63 Rail Pressure Sensor.

OK: The rail pressure of 0 kPa is shown.

Q. Is the check result normal?

	Go to Step 11.

	Go to Step 7.

STEP 7. Check harness between rail pressure sensor connector terminal and engine-ECU connector terminal FPS5.

Check power supply line for damage.

Q. Is the check result normal?

	Go to Step 8.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 8. Check harness between rail pressure sensor connector terminal and engine-ECU connector terminal FPSE.

Check earthing line for damage.

Q. Is the check result normal?

	Go to Step 9.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 9. Check harness between rail pressure sensor connector terminal and engine-ECU connector terminal FPS.

Check output line for damage.

Q. Is the check result normal?

	Go to Step 10.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 10. Replace the common rail assembly and fuel injection tubes.

After replacing the common rail assembly and fuel injection tubes, recheck the trouble symptoms.

Q. Does the trouble symptom persist?

	Replace the engine-ECU.

	The check is end.

STEP 11. Rail pressure check.

Connect the M.U.T.-III to check the following data list items.

Check that the value of Item No. 64 Rail Pressure Target is 20 - 35 MPa at idle speed and at 2,000 r/min.
Check that the value of Item No. 63 Rail Pressure Sensor at idle speed and at 2,000 r/min is within ±10 MPa of the value of No. 64 Rail Pressure Target.
Check that Item No. 67 Supply Pump Target Value is 1,700 - 1,900 mA at idle speed and at 2,000 r/min.

Q. Are the check results normal?

	Go to Step 12.

	Replace the supply pump assembly. After replacing the supply pump, learn the supply pump (Refer to GROUP 00 - Precaution Before Service - What The Common Rail Engine Learns <4N1> ).

STEP 12. Fuel pressure limiter valve function check.

Connect the M.U.T.-III to run the engine at idle speed.
Carry out the fuel leakage check according to the following procedures.

Select "MPI/GDI/DIESEL" from System select Screen of the M.U.T.-III.
Select "Special Function" from MPI/GDI/DIESEL Screen.
Select "Test" from Special Function Screen.
Select "Fuel leakage check" from Test Screen.

OK: The rail pressure should be approximately 200 MPa to be stabilized.

Q. Is the check result normal?

	Go to Step 13.

	Replace the common rail assembly.

STEP 13. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

	Replace the engine-ECU.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).