Posted in MMC L200

P0093 – Fuel Leak Problem MMC L200 IV

 Posted by  Posted on September 28, 2020

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

  • 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
  • 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.
  • Harness damage in rail pressure sensor circuit or loose connector contact.
  • Failed engine-ECU

    • DIAGNOSTIC PROCEDURE

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

    Q. Is any other diagnosis code than P0093 set?

    STEP 2. Detection of fuel line leakage

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

    • Q. Is the check result normal?

    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 trouble symptoms.

    • Q. Does the trouble symptom persist?

    STEP 4. Connector check: A-44 rail pressure sensor connector and C-105 engine-ECU connector.

    Q. Are the check results normal?

    STEP 5. Check harness between A-44 (terminal No. 1) rail pressure sensor connector and C-105 (terminal No. 70) engine-ECU connector.

  • Check power supply line for damage.

    • Q. Is the check result normal?

    STEP 6. Check harness between A-44 (terminal No. 2) rail pressure sensor connector and C-105 (terminal No. 64) engine-ECU connector.

  • Check output line for damage.

    • Q. Is the check result normal?

    STEP 7. Check harness between A-44 (terminal No. 3) rail pressure sensor connector and C-105 (terminal No. 88) engine-ECU connector.

  • Check earthing line for damage.

    • Q. Is the check result normal?

    STEP 8. Detection of fuel leakage from injector body

  • Remove the injector. Check whether there is the evidence of the fuel leakage from the injector body.

    • Q. Is the check result normal?

    STEP 9. 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 the trouble symptom persist?

    Author: admin