Code No. P0093: Fuel Leak Problem


OPERATION



  • Battery power is supplied from the engine-ECU (terminal No. 17) to the suction control valve (terminal No. 1).
  • The engine-ECU (terminal No. 3) turns on the power transistor to flow current to the suction control valve (terminal No. 2).

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.

PROBABLE CAUSES



  • Fuel leakage or fuel line blocked
  • Failed injector
  • Failed suction control valve
  • Failed rail pressure sensor
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

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

Q. Is any other diagnosis code than P0093 output?
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.

  • 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?
Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - 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 ).
Go to Step 4 .

STEP 4. Replace the common rail assembly and fuel injection tubes.

  • After replacing the common rail assembly and fuel injection tubes, re-check the trouble symptoms.

Q. Does trouble symptom persist?
Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - 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 ).
The check is end.